All posts by CFScott

I am a Coastal Skipper and owner of the yacht Baybreeze. I was formerly an academic at Department of Civil and Building Engineering, Loughborough University. My background is in applied mathematics, computing and physical oceanography.

Chichester Visit

Hi Folks,

I am a little overdue in posting this trip which occurred 17-19 April 2017. One reason is trying to figure what to write about that might be of interest to readers coupled with a desire not to bore people with the usual passage planning rigmarole in an area that Baybreeze often frequents – the Solent. So, in this post, I dispense with hours of departure and arrival and the need to plan passages to catch the tide and allow for tidal gates. Hence, a short post (completed mainly for the record)!

My guests on this sail were Mark Harrod and Rene Wackrow, two former work colleagues. Having left a little late in the day, we headed for a mooring buoy in the Beaulieu River arriving by mid-afternoon where we stayed overnight until departing  the next day at around 10am to head east with the tide.

My guests, Mark Harrod wearing a lovely hat (actually, the radar dome in the background) and Rene Wackrow waving. Blue skies!

 

 

 

 

 

 

 

 

 

 

 

As we past the easternmost part of the Isle of Wight and whilst close to high water, rather than head back west, we decided to head for Chichester Harbour to explore for the first time a nice anchorage within shown on the charts. A lovely spot it turned out to be!

After a two hour lunch break while at anchor, we then started making our way back again to the mooring buoy in the Beaulieu River for another overnight stay before heading back the Baybreeze’s berth at Shamrock Quay.

Solent fishing boat.

 

Shamrock Quay – Beaulieu River – Chichester Harbour track (17-19 April 2017).

The weather throughout was beautifully sunny, at worst partially cloudy. Total distance: 71 nm; engine hours: 6.2.

Next post: I report on my part in the ARC Portugal Rally commencing Sunday 4 June when I join Heinz and Barbara as crew on their 12m 46-year-old Dufour ketch (in-boom furling!) for the first leg from Plymouth to Baiona, Spain covering a distance of 550 nm across the Bay of Biscay.

Mupe Bay and Isle of Wight Circumnavigation

Preparations

Baybreeze’s Yanmar 4JH3E engine needed a basic service, so I thought I’d give it a go. In its previous service over 300 engine hours ago before departing for the Azores, just the engine oil and oil filter were changed. This time it was time to change the Racor fuel/water separator filter and the main fuel filter as well. This meant having to bleed the fuel lines of trapped air. The procedure is pretty straightforward:

  1. Engine Oil: Run the engine to full operating temperature (say 15 minutes) to reduce the engine oil viscosity thus making it easier to pump out. Introduce an extractor pump to the sump via the dipstick and extract the used engine oil. Add new oil to the engine so that the dispstick shows a final oil level about midway between the top and bottom limits (about 5.3 litres Heavy Duty SAE 15W-40 Engine Oil are required for this engine).
  2. Engine Oil Filter: Remove the old oil filter by hand or by using a filter wrench. It helps to enclose the filter with a plastic bag to catch any oil spillage. Moisten the seal of the new replacement oil filter with clean engine oil and and screw it on hand tight.
  3. Racor fuel/water separator: Unscrew the brass T-bar on top of the separator and remove the cover. Remove the old filter and replace it with a new one. Top up with diesel fuel, put the cover back on and screw the top back on.
  4. Engine Fuel Filter: Remove the fuel filter on the engine block and replace it with a new one. Moisten the seal with diesel fuel and hand tighten.
  5. Bleed the Fuel Lines: With the oil and all filters replaced, it is time to bleed the fuel of trapped air. The engine won’t start otherwise!
    Stage 1: Loosen the bleed nut on top of the fuel filter head. Use the hand pump located on the side of the engine to pump fuel through until it emanates through the bleed nut. This may take awhile. Then tighten the bleed nut.
    Stage 2: Crack open the nuts holding the injectors in place. Now crank the engine over (switch on, press start button) for about 10-15 seconds. Diesel fuel should now appear at the injector nuts. Now tighten the injector nuts.
  6. Fire up the engine! You’ll be pleasantly surprised to see and hear it run!

Everything else seemed to be in order and so we were ready to go.

My Guests

Our trip was planned for Sunday 9 April to Wednesday 12 April 2017. My guests for the trip were my farmer friend Shaun Taylor, a complete novice, and Murray Burton, an experienced day skipper and part yacht owner.

Shaun Taylor
Murray Burton

 

 

 

 

 

 

 

 

 

We planned to head to Newtown River for an overnight stay at anchor then to head off at about mid-flood tide so as to arrive at the Hurst Point tidal gate just as the tide was beginning to ebb, thence on to Mupe Bay.

Rig Check

A few weeks earlier I had tensioned the standing rig according to the Island Packet specifications. While under full sail I wanted to

Loos Gauge tension settings for temperatures less that 10 degrees Centigrade as recommended by Island Packet.

check the rig tensions, especially to see whether there was any degree of slackness on the leeward side under strong winds. This would indicate that there was insufficient tension.

 

On inspection I found the leeward rig to be too slack for the settings shown on the left. The Island Packet recommendation for temperatures greater than 27 degrees Centrigrade requires readings 3 points higher all round. I shall make this adjustment and recheck while under sail at a later date.

 

Can’t Stop the Engine!

After a night’s anchoring in Newtown River, we weighed anchor and headed towards the Needles Channel a couple of hours before high tide. We’d had just set the sails and tried stopping the

The engine fuel solenoid. The plunger covered by a rubber sleeve is to the right though not visible in the image.

engine but it failed to stop. The problem persisted after several attempts. Luckily, my farmer friend and crewman Shaun sauntered below deck and within a minute or so, the engine stopped. When asked what he had done, he said that he had located the fuel solenoid and pushed in the plunger. That stopped the flow of fuel to the engine thus stopping it. We were all relieved! I had also learned something new and that is always good!

Does the Prop Shaft Rotate When in Gear?

On the sail to the Azores, I was told that keeping the gearbox engaged would prevent the propeller shaft from rotating, thus preventing unnecessary wear on the shaft and stern gland. However, while making way under sail it becomes difficult to disengage the gearbox (i.e., put it in neutral, a requirement to start the engine) if the speed through water is more than 3-4 knots. So, the question is: With the engine off, does engaging the gearbox prevent the propeller shaft from turning? Well, apparently not! When the prop shaft was checked, irrespective of whether the gearbox was engaged or not, the prop shaft always rotated! This is still rather puzzling.

Mupe Bay Anchorage

Having departed Newtown River around 1000 BST, we arrived at our Mupe Bay Anchorage around 1530 BST, having travelled with the tide under a combination of motor and sail. Baybreeze being a heavy displacement long-keeler, I tend to motor when wind speeds fall below F3.

The Mupe Bay anchorage (the north end of Warborough Bay) looking north-east.

The overnight forecast was for gentle variable winds with a northerly component. I was woken by a wind change around 0230 BST to find the wind blowing F3 from the east. What a change! By the time of departure at 0500 BST the wind became a steady F3-4 from the west – ideal for our eastward return.

The Return Leg

Departed Mupe Bay Tuesday 0515 11 April, an hour or so before sunrise and close to low water. As the wind was a handy westerly, we expected to count on the tide and wind to take us all the way the the eastern-most point of the Isle of Wight when the tide would change and propel us towards Osborne Bay. There we would anchor for lunch and a light snooze!

The day was beautifully sunny and the wind a treat. All went to plan. However, our planned departure from Osbourne Bay at an hour or so before low water was a little late in making way for Beaulieu River where we planned to pick up a buoy for the night. The contrary tide started to pick up and the wind became a Force 4 southwester thus making it difficult to make progress against both wind and tide. Worse still, we appeared to be in the thick of ship traffic. While just north of Cowes, behind us a ship was approaching then decided to hold ground while a cruise liner approached the turning basin from the north. I guessed it was turning to port to head eastward – confirmed with a two blasts signal later. Following the cruise liner was a smaller cargo ship also with a pilot boat, its intentions unknown (headed west, as it turned out). Then there were the high-speed ferries coming from and going to Cowes. Quite a hair-raising experience while trying to make way against an Force 5 wind and spring tide in a sailing vessel approaching the precautionary turning basin!

Finally, when all dangers were clear and as we were not making headway we decided to call it a day and headed downwind and with tide for home at Shamrock Quay. How marvelously calm it is traveling with wind and tide after hammering against it awhile!

Nevertheless, a lovely day’s sailing!

Distance logged, 131 nm; engine hours, 12.

Baybreeze launched with a new rig!

Hi Folks!

Baybreeze has a new rig. Metric 8 mm and 10 mm 316 grade 1×19 stainless steel wire cables replace the original imperial 5/16″ and 3/8″ 302/304 grade stainless steel 1×19 wire cables that had been in service for the past 15 years – a replacement that had been long overdue. While the mast was un-stepped and taken down, the opportunity was taken to have LED lighting fitted throughout and old unused cabling removed. The purpose of this update is to report on the post-installation rig tensions and their adjustment.

Figure 1. Rig configuration.

Rig Configuration

Baybreeze has a cutter masthead rig with one set of in-line
spreaders, a keel-stepped mast,
and forward and aft lower shrouds. The rig comprises of 8 mm and 10 mm 1×19 AISI 316 stainless steel wire cable for which the minimum breaking load (MBL) for 8 mm and 10 mm wire cables are 5040 and 7870 kg, respectively.
 
To measure the cable tensions I used a model PT-3M Loos Tension Gauge which is used specifically for 1×19 stainless steel cables of 7, 8, 9 and 10 mm diameter. For convenience, Figure 2 shows the correspondence between the Loos Gauge reading (horizontal axis) and the tensile force in kilograms (vertical axis) for a 10 mm 1×19 wire cable.
Figure 2. PT-3M Loos gauge conversions for 10mm 1×19 stainless steel cable with high end extrapolation. Data from Loos & Co.

The graph shows a non-linear exponentially increasing curve with a the maximum shown Loos gauge reading of 53 equating to a tensile force of 1800 kg, i.e., about 23% of the wire’s MBL. Higher values are not provided by Loos & Co presumably because tensions would be well beyond what might be deemed to be the safe working load (SWL). For later reference, the smooth exponential fit shows extrapolated values beyond a reading of 53.

Island Packet 380 Recommended Maximum Rig Tensions

Fortunately, Island Packet in their IP 380 manual provide recommended maximum tensions using the PT-3 Loos Tension Gauge. This information is summarized in Figure 3 below. They were the tensions the rig was set to and sailed with before rig replacement.

Figure 3a. Loos gauge PT-3 not to be exceeded tensions, for temperatures less than 10°C.
Figure 3b. As in Figure 3a, but expressed as a percentage of minimum breaking load. There are marginal increases at higher temperatures.

 

 

 

 

 

 

 

 

 

It is interesting to note that all tensions in the Island Packet recommendation are close to about 10% of MBL. This differs significantly from Alan Barwell’s recommendation expressed in his book Rigging Handbook for Cruisers, where he writes (Ch5, p25): “Generally the rigging should be tensioned to about 20 per cent of the wire’s breaking strain…“. Note also that Ivor Dedekam in his book Illustrated Sail and Rig Tuning, p66, recommends tightening cap shrouds a little less, approximately 15% of MBL. Perhaps it’s a modern trend to have higher rig tensions? I am aware that racing yachts tend to use the maximum tensions that are structurally possible, but this is not a racing yacht, but a cruising one.

Results for Professionally Tensioned Rig

After the new standing rigging was installed, the rig had been professionally tensioned ‘by feel’. When questioned as to whether some sort of tension gauge would be used to check cable tensions, the suggestion was that they were experienced enough to know ‘by feel’ the correct tension. I decided to measure the tensions for myself when they’d finish. Figure 4a below shows the professionally tensioned rig readings taken with a Loos PT-3M, designed for 7, 8, 9 and 10 mm 1×19 316 grade stainless steel wire cables, while Figure 4b expresses those measurements in terms of per cent of MBL.

Figure 4a. Loos guage PT-3M tension readings after professional tensioning (2017).
Figure 4b. As in Figure 4a, but expressed as a percentage of minimum breaking load.

 

 

 

 

 

 

 

 

 

If the Island Packet 380 manual and Alan Barwell’s and Ivar Dedekam’s  quotes can be taken as a guide, it would appear that the rig was not only out-of-balance but had been significantly over-tensioned, so much so, that the tensile force for a Loos Gauge reading of 56 had to be obtained by extrapolating the data provided by Loos & Co (see Figure 2).

From the available information and the obvious tension imbalances, it is difficult to accept that the professionally set tensions were intentional but rather a result of an inaccurate ‘by feel’ approach. [Furthermore, the tension imbalances also serve to illustrate the potential degree of error of this approach]. I would imagine there would be an unwitting tendency over time for riggers to increase tensions ‘just to be on the safe side’. However, for a badly tensioned rig, it is of at least some consolation to note that a moderately over-tensioned rig is likely to do less structural damage than an under-tensioned one.

Tuning While Sailing

Figure 5. Diagram from Loos & Co. website.

According to Loos & Co:

There is a simple criterion for shroud tension. The initial rigging tension should be high enough that the leeward shrouds do not go slack when sailing close-hauled in a reasonably brisk wind….

If the shrouds are not set up with enough tension, the leeward shrouds will go slack when the boat is sailing to windward. This can result in fore and aft pumping of the mast in a head sea. This mast movement will change the shape of the mainsail and can cause performance loss as well as possible structural damage.

The ‘structural damage’ referred to would most likely be due to ‘shock loading’. Rig tensions has now been reset to Island Packet recommendations. What remains to be done now is to test the rig tensions while at sea.

Further Literature

  1. Ivar Dedekam: Illustrated Sail and Rig Tuning. Furnhurst Books, 2013.
  2. Alan Barwell: Rigging Handbook for Cruisers. RYA, 2013.
  3. http://www.riggingandsails.com/pdf/selden-tuning.pdf
  4. http://uk.boats.com/how-to/how-to-tune-the-rig-on-your-yacht/#.WMgDikdBphF
  5. http://www.ybw.com/forums/showthread.php?19654-How-tight-should-the-standing-rigging-be
  6. http://loosnaples.com/how-to-use-pt-series-tension-gauges

Exploring New Anchorages – Hurst Point to Portland

My guest on this four day trip was Rene Wackrow, a newly qualified Day Skipper and a former colleague of mine at Loughborough University. It was Rene’s first time on board and our plan was to explore a few of the anchorages west of the Solent as far as Portland Harbour.

We left Shamrock Quay on Monday 5 September at 1330 BST, arriving at Hurst Point around 1720 BST and anchored to wait for the tide to turn and take us through the Needles Channel. That meant an early departure at 0520 BST just before dawn the next morning. Winds were light so we resorted to motor sailing with the intended aim of anchoring at Swanage again to wait for a favourable tide to take us further west.

About halfway between the Needles and Swanage, I decided to try our luck at fishing over a wreck site as shown on the charts. We made several attempts to position the boat over the wreck but it failed to register on the echo sounder and so we gave up after 15 minutes of trying and continued on our journey arriving by a combination of motoring and sailing into an anchorage at Swanage at about 1010 BST. We anchored close to an anchored 10m yacht named Gracious Lady who had been in regular contact with the Solent Coast Guard over the past few hours. It seemed the Coast Guard were monitoring her progress perhaps towards her home port because of engine failure. While anchored, we had lunch, caught up on sleep then departed at about 1430 BST to catch the west-going tide.

We were hugging the coast headed past St Aldhelm’s Head. Just as we past the rather impressive tidal race near the headland, at around 1610 BST, we were intercepted and hailed via a loudhailer from a vessel not too dissimilar to a small tugboat asking us to switch to VHF Channel 08. This was the Range Safety Craft who indicated that firing practice was underway over the Lulworth Range and so, to avoid the seaward danger zone, we were asked to head on a compass course of 245° until we reached latitude 50° 33′ N at which point we could then head west. We were to continue to monitor VHF Ch 08 for any updates.

During our monitoring, we were both amused and disturbed by what was communicated with a yacht a few cables ahead of us. Here’s how the conversation proceeded as I recollect beginning at about 1610 BST (Tuesday 6 September), though the name of the yacht is withheld:

Range Lookout: Yacht X, you are in the danger area, sir.
Yacht X: I was just following the yacht in front.
Range Lookout: There are no other yachts in the danger area, sir. We not only have direct visuals but also multiple cameras overlooking the area, sir. Why were you not able to proceed as directed?
Yacht X: I had autopilot failure. My autopilot got stuck.
Range Lookout:
Could you not switch to manual?
Yacht X: No answer.
Conversation ceased.

At about 1617 BST, the Range Lookout communicated to the Range Safety Craft via Ch 08 to say that firing practice had ceased permanently though prematurely (by 43 minutes). The Range Safety Craft then communicated to us that we were now free to proceed as we chose though not to venture near-shore east of Lulworth Cove for a period after 2000 hours as firing practice would recommence. Throughout, the Range Lookout and the Range Safety Craft had conducted themselves in a most professional manner. Needless to say, we were not impressed by the impertinence of the yachtsman!

Under light winds and sunny skies we motored NE towards Worbarrow Bay to take a closer look. However, we were more impressed with Mupe Bay at its western extremity. Rather than anchor here for the night, we decided to head a little further west to Lulworth Cove as a possible alternative. Lulworth Cove turned out to be rather small and crowded (more suited to a lunch stop than an overnight one), so we decided, as the wind was picking up, to sail to Portland Harbour where we would be assured of a peaceful night at a quiet anchorage.

It was a pleasant sail and we arrived 1930 BST in Portland Harbour, anchored, dined, watched the setting sun and retired to our bunks, sleeping fitfully. Fifty metres away, Gracious Lady was also at anchor.

Over much of the following day, under sunny skies a Force 3 wind prevailed, initially SW then backing E during the day. We headed out to sea and tacked at about 1120 headed directly towards the headland and Studland Bay arriving 1500 BST and where we anchored for the night. The easterly wind had kicked up a little swell into the bay so the night at anchor wasn’t as comfortable. However, a cold front was expected overnight with wind becoming a strong westerly. Morning confirmed what was expected – a westerly Force 7 (gusting F8) wind and great for our downwind homeward leg of the journey. By the time we’d reached Shamrock Quay, the wind, still westerly, had moderated to Force 3-4. It had been a lovely trip.

Distance logged, 135 nm; engine hours, 12.

Bank Holiday Solent Jaunt August 2016

With me for a few days around the Solent on this Bank Holiday Weekend 27-29 August were Judith, Marcus and Beth. We departed 0930 BST on Saturday 27 August an hour or two after high water, headed for a mooring buoy on the Beaulieu River, a little upstream of the marina for a pleasant lunch in tranquil surroundings. We arrived around 1300 BST had a leisurely lunch and departed 1500 BST for our intended overnight anchorage in Newtown River on the Isle of Wight. Wind had been slight for most of the day so travel required the assistance of the motor!

We arrived at Newtown River anchorage about 1730 BST to find it quite crowded but managed to locate a nice sandy spot in 3m depth with sufficient bottom clearance allowing for the tide. Instead of the recommended anchor chain deployment of six times the maximum anticipated water depth, I deployed half that amount, expecting that the anchor would still hold, in spite of the two or so knot tidal current. By late evening at high tide, the anchor still appeared to hold nicely, so, having set my anchor alarm at 50m radius, I though nothing more of it, and retired to my berth for a fitful sleep. However, I was in for a surprise the next morning. Baybreeze had dragged anchor about 30m farther upstream with the incoming tide! The yellow yacht we had anchored next to was some distance away and thankfully we were still quite some distance from other yachts, so a collision was avoided – and hence a gracious way to learn a lesson! Six times the water depth it is and never less!

We departed at 1000 BST at high tide and headed for Cowes Yacht Haven. Although against the tide, the wind was a moderate south-westerly and so we arrived and was at the berth by midday. That left the remainder of the day sight-seeing followed by an evening’s restaurant dinner with friends Rosemary and John who live on the island.

The next day, Monday, was the best of the three. The bow thruster was playing up and so I had to ‘spring’ off the berth reversing out then forward and out of the marina without a hitch. Because the wind was light we had to motor to our next destination, Osborne Bay, for a swim and lunch.

2016-08-29-13-17-50
Nicely anchored in Osborne Bay and in for a swim!

As we left Osborne Bay, the wind started to pick up to F4-5 nicely again from the west and we sped north with full genoa and main across the eastern side of Bramble Bank in sunny conditions, the below-keel water depth sometimes reaching a low 1.5m. Great sailing weather! As we entered Southampton Water, the sail training square rigged vessel Stavros motored out. Alas, the wind soon died and we had motor up Southampton Water back the Baybreeze’s berth at Shamrock Quay.

It was Beth’s first sailing experience and it appears we have a new enthusiast!

Distance logged, 48 nm; engine hours, 8.2.

West Country Cruise

Crew and Planned Destination

It was originally planned to sail to Ireland’s south and west coast. As crew member I invited Greg Peterson, a former fellow student of Mathematics at the University of Western Australia and with whom I had shared a semi-derelict house in Ruislip Street, West Leederville, Perth, in our student days. I’d invited Greg for a three-day sail in the Solent the previous year stopping overnight by Cowes Yacht Haven and Ocean Village Marina to attend The Ocean Cruising Club (OCC) Boat Show Dinner at the Southampton Yacht Club. Despite the very autumnal weather with the cold,  rain and strong winds, and knowingly not immune to the odd bout of seasickness, Greg bravely elected to accompany me on a cruise to Ireland via the West Country planned for the following year.

Greg arrived on Sunday 26 June at the Southampton Bus Station and was duly collected and welcomed aboard. He appeared well prepared for the trip, having participated in yacht crew training over several weekends during Perth’s summer months. All that was needed was a little Stugeron!

Engine Repairs

Although the weather was fine, our departure was delayed for several days while engineers from Motive Marine at Shamrock Quay ordered and fitted replacement parts for a corroded oil cooler and salt water heat exchanger on Baybreeze’s Yanmar 4JH3 diesel engine. Admittedly, the engine should have been checked months before and the repairs made in a timely preparation but that wasn’t to be the case.

A Leaking Boat!

By Wednesday afternoon, the engine work had been completed, our supplies and gear were on board and I felt we were ready to depart early the next day. However, when returning to the boat at its berth after a brief departure, I was surprised the hear the bilge pump roar into action just as we walked by. Several litres of bilge water was being discharged overboard! Ugh! A leak somewhere on the boat!  Alas, a quick look at the stern gland on the prop shaft revealed an ingress rate of about a drop every second – about four times greater than what it was just before she was hauled out of the water and onto the hard seven months earlier. I concluded that it was not so serious as to delay our departure but, nevertheless, needed to be monitored in case it worsened.  I expected the drip rate to return to normal as the stuffing box re-hydrated over the next week or so (which turned out to be the case).

Thursday 30 June 2016: Shamrock Quay to Studland Bay

I elected to leave at 0415 UTC (0515 BST) leaving against the mid-flood tide with the prospect of hitching a ride on a fair tide though the Solent, through the Hurst Narrows and out via the North Channel to head for a Studland Bay anchorage. We arrived in at about 1230 UTC, anchored, admired the scenery and rested. The next day’s journey was expected to take about 14 hours and a timed departure was needed to negotiate the Portland Race with a fair tide.

Friday-Saturday 1-2 July 2016: Studland Bay to Torquay

We departed 0500 UTC as planned with a SW wind expected to increase to Force 6/7. This meant serious tacking against headwinds and increasing waves (as the track at the top of this post shows). By the time we reached the Portland Race, the waves had increased to moderate/rough. There was a Pan-Pan VHF transmission from another yacht asking the coastguard for assistance as they could not make progress because of the sea state. Soon after passing the Portland Race in strong Force 7 winds the relatively new half-furled genoa furling line broke near the furling drum. Suddenly, the genoa quickly unfurled and became fully deployed! If the wind increased in strength, the boat would have excess sail. Something needed to be done urgently.

My first response was to try trying the broken ends together and rewinding much of the line around the drum so that it could at least be partially furled until a sheave came in the way of the knot. It was soon realized that this wasn’t going to work very well. I thought of the possibility of dropping the genoa but that would have meant cutting the engine to avoid fouling the prop in the likely event that it spilled overboard during the process. Being short-handed would have made the task more difficult. At the pulpit, the waves continued to wash over my feet.

In the meantime, Baybreeze, with both main and genoa fully deployed, was pitching under motor heading into the waves with Greg ably at the helm. Fortunately, I had kept the original genoa furling line on board as a spare. I retrieved it, removed the offending line and proceeded to install it. While in the process, the genoa suddenly backed and we found ourselves unwittingly hove-to! What a transformation! Whereas before, the waves were spilling over the foredeck, now the boat was far less agitated almost to the point of being serenely tranquil! I could now easily get on with the job of reinstating the old furling line. Within an hour, the problem had been rectified and we were underway again. Had I been properly prepared the job would have taken 15 minutes perhaps!

DSCN0512_1
Threading the replacement furling line 25 times around the furling drum in strong winds!

[Although hove-to on a starboard tack, the large genoa had backed onto the standing rigging – not an ideal situation. Nevertheless, it worked in the sense the boat steadied quite remarkably. A previous attempt at heaving-to was on return from the Azores using the mainsail and the much smaller staysail. This was not considered a success as the boat pointed way too far off the wind (at about 60-70 degrees) and she showed little sign of steadying.]

Making headway under sail alone against wind and wave (and later tide) slows down a heavy displacement boat like Baybreeze, so the remainder of the journey was motor-sailed. Maintaining some sail was essential for a more comfortable ride as the yawing motion of the boat was greatly diminished. We finally arrived and anchored in Tor Bay in the wee hours at 0315 UTC the next day. A journey I expected to take about 14 hours took 22! It was time for a rest and a lie in!

Later that day we relocated to Torquay Marina to make use of the facilities and to look about town in earnest the following day. We replenished our food supplies, then took the road train for a visit to Torre Abbey which turned out to be well worth the visit. However, the road train driver’s recommendation for the best fish and chips in town turned out to be the opposite!

Monday 4 July: Torquay to Plymouth

After staying two nights at Torquay Marina, we set off on Monday at 0700 UTC for Plymouth. Intermittent fog and light winds were forecast for the day. As we rounded Prawle Point, there was little wind so I decided to start the engine. But, alas, the  engine wouldn’t start! I checked to make sure that the engine gear was in neutral as it wouldn’t start otherwise and that appeared to be the case. Another problem! The only consolation here was that there was just sufficient wind to sail into Plymouth, a journey that would take about four hours, so I had plenty of time to figure this one out. We had to do a quick tack when the cliffs of Prawle Point appeared dead ahead through the fog about a cable and a half away, much sooner than expected!

While I was going through the motions of various checks, Greg questioned whether the engine gear was, in fact, in neutral. I asked him to put it in what he thought was neutral. He did so, and woe and behold, the engine started! Phew! The indirect cause of this problem was placing the gearbox in reverse while sailing with engine off, a practice recommended to me by people with far more experience, so as to prevent the propeller shaft from turning and thus preventing unnecessary wear. However, this practice made it difficult to place the gearbox in neutral even in modest through water boat speeds. Therein lay the problem.

20160704_190158
The statue of Sir Francis Drake on Plymouth Hoe.

Much relieved, the fog lifted and the SW wind increased in strength. We were able to reach our berth at Plymouth’s Queen Anne’s Battery at 1515 UTC. We stayed a couple of nights taking the opportunity to visit Plymouth Hoe where, earlier that day, American Independence Day had been commemorated, as well as the waterfront and the Plymouth’s National Marine Aquarium.

Wednesday 6 July: Plymouth to Helford River

DSCN0575_1
Baybreeze at anchor in the Helford River, Cornwall.

We departed Plymouth 0500 UTC for the Helford River. Only in the later stages did the wind increase from NNW Force 1 to SSE Force 4 which meant motoring much of the way. We arrived at 1345 UTC and anchored in this lovely tranquil picturesque place with a couple of square-rigged vessels anchored nearby. In the afternoon, we rowed ashore in the inflatable dinghy to visit the tiny picturesque village of Durgan.

Thursday 7 July: Helford River to St Michael’s Mount

Departed Helford River 0915 UTC accompanied by the square-rig sailing ships all of us heading towards Lizard Point with the wind S at F4. As we neared Lizard Point, I noticed one of the square-riggers, having stayed close to shore, was now neatly tucked in possibly at Cadgwith Bay in the lee of Lizard Point. Depending on wind strength and direction we would head for either the western anchorage next to St Micheal’s Mount or anchor in the lee just south of Newlyn Harbour Entrance. I elected to anchor near St Micheal’s Mount arriving at about 1800 UTC and greeted by several young women training in a row-boat and braving the cold wet weather. A great welcoming party!

20160707_194828_1

Friday 8 July: St Michael’s Mount to Falmouth

The choice of anchorage wasn’t the best, as we were exposed to a slight swell which made the night less comfortable. We departed 0600 UTC for Falmouth but, before doing so, thought we’d just take at look at the Newlyn anchorage. As expected several yachts were anchored there having obviously had a very peaceful night!

The journey to Falmouth took about five hours arriving at about 1415 at the Falmouth Visitors Yacht Haven. We spent a good 20 minutes looking for the two leading line markers on shore to guide us through the dredged channel to the Yacht Haven, as suggested in Tom Cunliffe’s The Channel Pilot, but only managed to find one. Luckily, we managed to wave down a staff member in a runabout who guided us through to a berth, rafting next to the yacht Capricorn. It turned out that the second mark no longer existed as sectored lights had been placed on the remaining mark – something we failed to spot!

We stayed  a couple of days in Falmouth, visiting the Cornwall National Maritime Museum with its Viking display and enjoyed ‘proper’ fish and chips!

Sunday 10 July: Falmouth to Fowey

We left our Falmouth berth at 0700 UTC as planned with the town bell chiming as we did so. Such discipline was repeated on a number of occasions! [Well done to my guest, Greg, who appreciated the value of a timely departure and cooperated admirably]. As we motored off the berth to enter the dredged channel, the bow thruster failed to switch off and so had to be deactivated by the master switch. Another wee problem which meant I had to maneuver Baybreeze into her berth back at Shamrock Quay without its aid – a good test of seamanship!

DSCN0641_1
A great Sunday lunch to be had at the Gallants Sailing Club in Fowey.

We arrived 1115 UTC at the entrance to Fowey in Force 5 winds and moderate seas on a rising tide. We berthed on a pontoon opposite the China Clay Works some distance upstream and soon after called for a Water Taxi for a ride into town for a very pleasant and substantial Sunday roast lunch at the Fowey Gallants Yacht Club followed by a walk around the town.

Monday 11 July: Fowey to Salcombe

We departed Fowey at 0530 UTC headed for Salcombe with Force 5 WSW winds and moderate following seas – ideal sailing weather.

DSCN0644_1
Fisheries Research Vessel Cefas Endeavour.

In clear weather halfway across the Plymouth Bay, the Fisheries Research Vessel Cefas Endeavour started bearing down on us and shortly before reaching us gave us a courtesy call on the VHF radio identifying themselves and to ask if we would maintain our course as they they were engaged in various maneuvers that were likely to cross behind and in front of our path. We were happy to oblige as our path continued to remain headed straight for Salcombe.

On much of our West Country cruise, fishing vessels were not uncommon, many still displaying a red ‘Leave’ the EU flag from the 23 June referendum.

20160711_161030
The entrance to Salcombe Harbour looking seaward.

We arrived at Salcombe entrance at 1130 UTC negotiated its sandbar and motored along a series of channel bouys on the port side and picked up a yellow hi-vis mooring buoy for the overnight stay.  Soon after, sixty odd Merlin class dinghies came bearing down amongst the moored yachts weaving their way around and past them and then returning. This is a sailing coastal town! What a spectacle! These races were repeated again the following morning, delaying our planned departure at 0930 UTC by half an hour or so. As was customary, we caught a water taxi and had a good look around town that afternoon.

Tuesday 12 July: Salcombe to Dartmouth

We departed Salcombe at 1000 UTC for the four hour sail to Dartmouth. On arriving we motored up the River Dart as far upstream as Dittisham, just before which are some lovely moorings in tranquil tree-lined river banks. On our way there, the tranquility was temporarily broken as steam bellowed above the treetops from a  train as it travelled northward on the Kingwear side of the river. Ferries made their crossings, one pulled by chain, others transported by tugs just as they had been a hundred years ago. Trainees from the Britannia Naval College conducted their exercises in small dinghies.

We returned down river to berth at Deep Water Pontoon 2, fetching a water taxi soon after for a lift to town and then a walk to the 14th century Dartmouth Castle and up the hill for a view overlooking the bay. On return to the town, we entered a pub overlooking the fishing boat lock in time for a ‘curry night’. Perfect!

20160712_180210_1
Racing dingies crowding the river Dart’s entrance.

Wednesday 13 July: Dartmouth to Studland Bay

The return journey across Lyme Bay wasn’t expected to be as tiring as the outward journey for the WSW wind, though initially light, was with us. We departed 0600 UTC (with the town bell chiming as we did!) and motored into Lyme Bay until a NW F3 wind picked up at around 0820 UTC. We spotted no fewer than five tall ships in Lyme Bay, including the Norwegian training vessel Sørlandet.

By the time we’d reached St Alban’s head and after negotiating the Portland Race, the wind had picked up to W F5. As it was near slack water at neap tide, we safely navigated directly over St Alban’s Ledge past the bright yellow marker buoys used for target practice by the military. We arrived at the Studland Bay anchorage 1930 UTC.

Thursday 14 July: Studland Bay to Shamrock Quay

Departed 1030 UTC for safe passage through the Needles for a flood tide expected to start around 1230 UTC. Arrived at Shamrock Quay 1745 UTC and maneuvered into Baybreeze’s berth without a bow thruster! What seamanship! That was with motor. Maybe I should try with sail only next time!

Some of the tall (and not so tall) ships seen on our cruise.

I didn’t make it to Ireland or even the Scilly Isles – that will have to be another time!

Distance travelled: 498 nm; over 98 daylight hours and 7 night hours. Total engine hours: 46 (fraction of time on engine = 43%!).

Winter on the Hard

It has been quite some time since my last post in December 2015 describing a Channel Islands cruise in mid-October. On return from the Channel Islands, I had Baybreeze’s hull slurry blasted down to the gelcoat layer thereby removing multiple layers of crusty antifoul accumulated over a dozen or so years as well as the epoxy GelShield layer (greenish is colour). This was with the intention of coppercoating the hull – a method of more environmentaly-friendly antifouling that, with just one application, protects the hull from barnacles and the like for a period in excess of ten years. The only drawbacks of coppercoating that I am aware of is that it is less effective in keeping at bay the accumulation of vegetable material (green slime!). However, this is easily removed by an annual pressure wash. Perhaps the other drawback is a lack of a choice of colour. Unlike conventional antifoul, coppercoat, although initially copper-coloured,  ends up in a bluish-green verdigris colour.

2015-11-14 08.38.17
Slurry blasting the hull…
2015-11-15 11.35.47
…the end result.

After allowing sufficient time for the hull to dry out after slurry blasting, moisture content readings using a Tramex Skipper Plus Moisture Meter (purchased from Nigel Clegg and Associates) were taken a regular intervals on the hull. Higher readings are indicative of osmosis which, in severe cases and over many years, leads to a chemical breakdown of the fibreglass resin, water retention and blistering! Fortunately, all readings, except for the rudder (which can easily be replaced), were in perfectly acceptable limits indicating that the epoxy GelShield layer had been an effective moisture barrier.

The next stage was preparing the hull for coppercoating. The antifoul and GelShield had to be removed from near the waterline as slurry blasting stopped short of the topsides to prevent any damage to the gelcoat and also from where hull support pads prevented slurry blasting. On the keel, a couple of minor ‘holes’ perhaps a centimetre wide and a couple of millimetres deep, and a few lesser ones, were filled with epoxy filler. The final stage in hull preparation was sanding down the (below-waterline) hull to a uniform smoothness using 800 grit disc on an orbital sander. Try holding a kilogram weight orbital sander above your head for hours on end! Hard work!

The hull was now ready for coppercoating. However, as the uncured coppercoat epoxy is water-soluble, and being outdoors, a rain-free 48 hour window and temperatures, preferably in the teens centigrade to speed up the curing process, were needed. These conditions began to prevail in May 2016 although the first planned attempt had to be aborted as the weather forecast changed for the worse. Eventually, the job was done, the four coats taking two people about 18 man-hours of effort. After a five-day curing period, the supports were repositioned and another weather window was required to coat the parts of the hull where the supports had been – so another couple of weeks delay!

coppercoat1
The coppercoated hull just prior to re-launching.

After all the coating had cured, the coppercoated surface was given a light sanding both to expose the copper particles and to smooth the hull surface. The gelcoat topsides at the waterline adjacent to the coppercoat was finely sanded with 2000 grit wet-and-dry sandpaper and the topsides washed and polished.

The removal of the bow thruster propellers proved to be a little more difficult as corrosion had bonded them to the shaft. They were eventually freed by gentle persuasion, and a new anode and coppercoated propellers installed with the shaft generously covered in corrosion protective Lanocote.

Baybreeze was finally launched on Monday 20 June – quite a period on the hard.

——————————————————————————-

Here’s a lovely quote for this post, thanks to LH for drawing it to my attention:

“Houses are but badly built boats so firmly aground that you cannot think of moving them. They are definitely inferior things, belonging to the vegetable not the animal world, rooted and stationary, incapable of gay transition…. The desire to build a house is a tired wish of a man content thenceforeward with a single anchorage. The desire to build a boat is the desire of youth, unwilling yet to accept the idea of a final resting-place.”

from “Racundra’s” First Cruise – Arthur Ransome, 1923.

——————————————————————————-

Next cruise: Ireland and perhaps Scotland’s West Coast.

Channel Islands Revisited

At the Southampton Boat Show, Len Hiley entered a competition and was soon informed that he had won  a couple of free nights at each of St Peter Port and St Helier Marinas. Rather than have them expire, Len kindly offered them for use on our planned 7-14 day voyage to the Channel Islands and back. The two of us set off at midday on 11 October catching the fair tide for the 4-5 hour journey to Hurst Point at the western end of the Solent. The plan was to  anchor there for a few hours rest until the tide ebb again set in.  That would mean a 2300 hour departure for the overnight 12 hour 60 nm journey to Braye Harbour in Alderney.

Having departed at mid-night, as anticipated we arrived at Braye Harbour at midday having experienced an overcast sky with gusting F4/5  NNE wind for the entire journey. As the tide was with us when we arrived we could have continued on towards Guernsey or Jersey but decided to stop at Braye for a rest. It was probably not the best idea! As Tom Cunliffe notes in The Shell Channel Pilot, 7th Edition, p314:

Braye is safe in all weathers except strong northeasterlies. When these are threathened, only the ill-advised, the desperate, or the certified madman would come here. It can be generally uncomfortable with winds anywhere in the northern quadrant, but with this borne always in mind it is otherwise an all-weather, all-tide refuge of unique character.

We radioed the Harbour Master and was warned to double up on the mooring lines for the night. Quite a bumpy night though no more uncomfortable than anything experienced so far.

The wind continued from the NNE but picked up a little to F5/6 by morning. After checking in with customs we headed out about 0930 around through The Swinge towards Jersey. Seas were slight, the weather fine and visibility good. Lovely downwind sailing.

2015-10-13 15.46.26
Hawk-eyed Hiley surveys the scene as we round La Corbiere on Jersey’s south-west coast.
2015-10-14 17.02.22
Inside the St Helier marina. The sill at the entrance is  tidally operated requiring no additional power.
2015-10-14 12.27.29
Memorial to the Second World War occupation of the islands.

We arrived in St Helier on the Island of Jersey at around 1600 and found lots of visitor berthing space as we were well past the peak season. We made good use of the marina and its facilities with our two-day free pass and strolled through much of the port. After a pleasant two days’ stay we departed 0640 on Thursday morning taking the inner route south of the island while heading west and around La Corbière towards La Grande Grève, a bay on Sark’s west side separating Little Sark from Big Sark via the narrow connecting strip of La Coupée. The wind continued from the NNE at F5 strength so the lee of the island with its high cliffs afforded a tranquil shelter.

2015-10-16 10.55.53
Baybreeze anchored at La Grande Griève, Sark.
2015-10-16 10.56.33
The steep climb up the slopes to the road atop La Coupée.
2015-10-16 12.38.03
Vehicles are forbidden on Sark – only horse-drawn cart and tractors!

We arrived at about 1045, anchored and used the dinghy and outboard to explore the bay in more detail including Havre Gosselin and the Gouliot Pass. We climbed up the steep side of La Coupée and spent much of a day walking around the island and finding out about its colourful history. From around 1830 to 1842 many silver mines were cut, some from land initially then out to sea under the sea bed. During storms, miners could hear the rumblings of boulders on the sea bed above!

As the wind persisted from the NNE, we were in no hurry to be heading back across the channel towards the Solent as it would mean a tiring amount of tacking against headwinds.  However, a short sail across to St Peter Port in Guernsey would mean winds just forward of the beam – a much better option. Besides we had a second two-day free pass, this time for the St Peter Port marina!

When to depart our anchorage was a key question for our passage plan for arriving at St Peter Port. Neptune software (for passage planning) indicated the best time to be around midday of Saturday 17 October, yet Tom Cunliffe’s The Shell Channel Pilot indicated a departure of around 0500 being the best given the state of the tide. This appeared to be very puzzling. We opted for the accumulated wisdom of the Channel Pilot and departed 0500 and found ourselves arriving much sooner than the Neptune software had predicted. I think this is definitely a failing of the Neptune passage planning software. It appears unable to accurately predict passage times in tidal areas over short distances, most likely due to the paucity of tidal information.

The journey took an hour and twenty minutes and saw us alongside the fuel pontoon awaiting opening time. Once refuelled and with the tide sufficiently high to navigate the sill at the marina entrance, we motored into the virtually empty marina. We stayed a couple of days taking the opportunity the travel around the island on a bus for the cost of a single pound – a journey which took only a couple of hours.

We headed out of St Peter Port on Monday  0700 19 October with smooth seas, light winds and continued persistent NNE winds. Our destination was for a sheltered bay on Alderney’s south coast or, failing that Longy Bay on the island’s NE coast. Needless to say, with the wind direction as it was, we had to tack and sometimes motor most of the way. On approaching we opted for the anchorage at Longy Bay as it brought us nearer to home for the final leg. Telegraph Bay on Alderney’s south coast appeared less inviting.

2015-10-19 16.38.20
Longy Bay, Alderney looking south with La Rocque Pendante clearly visible.
2015-10-19 16.37.17
Longy Bay, Alderney, looking north towards Fort Raz.
2015-10-19 12.18.28
Longy Bay, Alderney, looking south west.

The bay is quite small as it is bound by submerged rocks towards the north. It afforded only marginal protection against the NNE winds especially during the flood tide when the boat would turn beam onto the waves as it refracted into the bay.  Nevertheless, quite a pleasant couple of days were spent anchored here waiting for a change of wind. Eventually, the forecast indicated a veering to the NW in a couple of days time and so we headed out from our anchorage towards the Solent on Tuesday 2000 20 October. Initially the winds were light, but by 0300 winds starting becoming westerly as forecast. It was plain sailing again. It had been a persistent NNE wind for the past 8 days! In fact, our speed was better than expected and we feared arriving well before the Needles tidal gate would allow. Nevertheless, it turned out well, having arrived just as the tide was flooding.

The rest of the trip was plain sailing with both a fair tide and a wind behind us. We arrived at Shamrock Quay at 1300. Another lovely trip. Total sea miles: 278 nm. engine hours: 11.3, over 10 days with 21 hours of night sailing.

 

Tandem Sail

It was a year ago that I first met Frenchman André Reze. He had berth next to Baybreeze at Shamrock Quay for the night making use of Marina Developments Ltd (MDL) Freedom Berthing scheme. He’d just arrived having crossed Lyme Bay and the Bill of Portland and recounted when a huge wave seemed to come from nowhere and land in his cockpit. He’d travelled with the tide but was not aware of the dangers of the Portland Race!

Portland
How it looks. A 60′ yacht caught in a blow in the Portland Race. Image courtesy YBW forum.

He’d just completed a circuit in his yacht Eden, a Beneteau 400, around the southern and eastern coasts of Ireland and the west coast of Scotland, much of it single-handed. I had loaned him a pilot book for the day and that evening we’d got together over a few glasses of French red wine. He explained to me his successful fishing technique which was to locate a shallow seamount or wreck passing over it a few times with fishing lure dangling overboard. His fish catch was recently supplemented by clawing a bucketful of cockles on the Hamble Point mudflats at low tide.

2015-08-13 08.23.33
Cockles galore!

He expressed a fondness for the English and was keen to improve his spoken English, so we agreed to keep in touch.

André arrived back a year later having completed a similar circuit on coasts adjacent to the Irish Sea. His track is shown below. Where his track crosses several times over a sea mount, you’ll know that’s where he’d been fishing!

Much of trip was, as before, single-handed, except for a three week period, when he took on a French crew at Oban. As he was about to head back for his home port on the Britanny coast, I suggested we head back together in tandem, as least as far as Torquay, where I would leave him to continue his journey and I would return to Shamrock Quay. I agreed to ‘collect’ him as I passed Ocean Village Marina, where he was berthed, at 0830 on Friday 28 August. Leaving a mid-flood tide always seemed a good idea as the Needles tidal gate would be in ebb as we transited.

2015-08-28 12.44.24
Turbulent ebb tide flow on leaving the Solent and entering the Needles Channel. Hurst Castle is in the distance.

2015-08-28 12.45.26

2015-08-28 13.23.32
Eden as she passes through the Needles.

Much of the journey was pleasant and without incident, except for an autopilot failure on Baybreeze soon after departure which meant my being stationed at the helm for the entire eight-hour journey without a break from mid-Solent to Studland Bay where we anchored for the night. The steering lock was of little use, as the boat would turn, head into the wind and lose speed. Fortunately, it was a recurring problem and one which I was familiar with and so was easily repaired while at anchor.

2015-08-29 08.22.35
Eden becalmed while crossing Lyme Bay.

An early 0600 start to catch the tide the next day (Sat 29 August) was hindered by a lack of wind the entire day so we motored the whole journey from Studland Bay to Tor Bay, some 70 nm or about 14 hours. Fortunately, the autopilot behaved well and I was able to be relieved of the helm for many hours. We passed about 3 nm off the Bill of Portland and, even at this distance, the ride through ‘the Race’ was bumpy. What is really interesting is how propeller efficiency appears to reduce in highly turbulent waters. The difference  in speed over ground (SOG) and speed through water (STW) tended to remain the same although both reduced as the race was traversed.

2015-08-30 19.06.14
Anchored in Tor Bay for the night.

We arrived at Tor Bay at about 2300 hours to an easy-to-find anchorage. While we had rafted the boats together for a brief period during the evening while anchored in Studland Bay, on this occasion we decided to anchor apart for fear of our masts colliding and causing damage as a result of wind or wave action.

Waking up to now visible new surroundings is always a delight and in Tor Bay this was no exception. A lovely bay with easy access though perhaps not so comfortable in an easterly wind. During my brief stay the light wind was NE so all was well. André motored over in his dinghy, we had lunch together and revelled in how lucky we were to be able to enjoy such freedom.

We parted company about mid-afternoon. A decision now had to be made for when to undertake the return journey. A lovely F4 northerly breeze was forecast making conditions for the sail back ideal. Catching the tide meant either an  early morning departure at 0100 (Monday 31 August) arriving in Studland Bay in daylight hours (mid-afternoon) or departing 1100 and arriving in darkness. It seemed the former was the obvious choice. A catching up on sleep was called for!

The sail back was pleasant with all sails fully deployed and no sail changes except for the final moments tacking into Studland Bay. This time I decided to give Portland Bill an even wider berth – 5 nm!

I anchored in Studland Bay overnight and departed 0630 the next day (Tuesday 1 September) to catch the spring ‘supertide’ back to Shamrock Quay. I decided on the route through the main Channel rather than the North Channel and, as the wind direction and strength was right, was hoping to sail Baybreeze through it. Alas, I had misjudged the strength of the tide and found myself being set off track onto the Isle of Wight. The idea of sailing through had to be abandoned and the motor started and run only for a short time to put us on track. [This is evident in the vessel’s track shown below. What would I have done if the problem have been compounded by engine failure? Turn the boat southward helped by the northerly wind, then figure out the next move! When single-handed, one has fewer options!].

2015-09-01 09.31.11
2015-09-01 09.31.11: RNLI to the rescue of a grounded yacht driven onto the Shingles by the ‘supertide’.

Another yacht wasn’t so lucky and found itself grounded on the west side of The Shingles bank probably set there by the strong flood supertide that prevailed. I first noticed her as I entered the Needles, keeled over, with foresail out but going nowhere. On approaching Hurst Point, a call for assistance was answered as an RNLI lifeboat sped past.

Catching the tide is a ‘no-brainer’. At times Baybreeze’s COG was 10 knots. Speedy! Less time at the wheel, more time to relax, less tiredness! I arrived at Shamrock Quay as the flood tide abated and managed to berth Baybreeze confidently and without assistance! A lovely trip.

Statistics
Distance travelled: 232 nm. Engine hours: 15. Overnight hours: 10.

Next planned trip
The Channel Isles and the north Brittany Coast, mid-October 2015.

Weather Routing

Just a brief post as a follow on to the last describing the return journey from the Azores to England. I was impressed by the idea of using a weather router as a passage planning tool to try to avoid the worst weather and sea conditions and so decided to write my own. It uses the most commonly used approach – the isochrone method – which, however, is not without its deficiencies. For example, it is unlikely to work for all configurations of Zermelo’s Problem, that is, for a vessel travelling at constant speed in a linearly sheared current (here, the boat’s heading is the control variable) and for which there is an analytical solution (see Bryson and Ho, Applied Optimal Control, Halstead Press, 1976, pp77-79). This provides quite a nice challenge!

ZermeloProblem
Optimal trajectories in a linearly-sheared current.

At present, the code does not include time-varying currents but uses the boat’s polar performance diagram to find the fastest sailing route under the varying wind conditions subject to maximum upwind and downwind wind constraints. What is also useful is overlaying wind vorticity on the map which provides a clearer indication of weather front location. At present, the code only accommodates maps with a Mercator projection.

Below is an image of the main window in mid-optimization with Grib weather forecast data provided by the NOAA GFS model. Red wind barbs are Beaufort Force 8 and above (greater than 34 knots true wind speed).

display

 

isosegments
The isochrone method showing isochrone segments.

A runnable jar file, WeatherRouter v1.1,  can be downloaded and run on any PC by following the README instructions. Access to the java source code will depend on developer interest. Feedback is welcome. Please be aware that this is version 1.1 amounting to just a few weeks work. There is a lot more that can be done. Happy Routing!

Postscript: V1.1 uses coastline shape files allowing greater world coverage and eliminates the need for specific map projections.