Cariad Bristol Pilot Cutter

By Dave M 14 entries 30 Sep 2012 — 6 Jun 2013
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Chapter 02 / 14

14 chapters · Page 1 of 2

Cariad Bristol Pilot Cutter

Started over a year ago, built from the Chris Brown fibreglass hull and plan. Got sidetracked with the Olympic build but completed this year. As well as the sails there is a small electric motor to help with recovery on calm days and to avoid the occasional water plant bank!

There are two winches controlling the sails - an arm winch works the mainsail with a drum winch controlling the fore sails. I have tried to make the running and standing rigging as accurate as possible and made all the pulleys / deadeyes. The deck is planked with pine strips and mahogany veneer covers the rear cabin and cockpit. Masts are pine suitably dyed. I made the sails from the plans supplies but am not happy with the finished result and will remake in time.

I have had several sails in most conditions and the model sails but not as well as I had hoped - not down to the design - probably my poor sails.

There is 4.5Kg of lead in the hull and I remove this to assist with transport. Today was a very blustery day and I was lucky to make it back to shore as the boat was blown flat and shipped a lot of water. This entered via the rudder post and rear cockpit so a rethink is necessary.

There is a solid keel so recasting the lead so it is all outside the boat and attached to the keel should bring the CoG much lower and Improve stability.

I show the model "as is" on one of the quieter days on the lake but will show more details as I progress.

Cariad Rear Cockpit and Rudder

The rudder is angled to align with the keel. The post rises thro the deck and has an arm attached, which the pilot used to control the rudder from the cockpit. in practice this required a push pull arrangement to transfer the servo travel to the rudder post. A brass bush fixed by grub screw carries two brass arms which connect via cable to the servo mounted below the open cockpit. I had constructed a push fit cover over the post to partly seal the hole. Clearly this is not sufficient and I will be sealing this completely, probably with a bespoke silicon casting this fits the hole and can be covered with wood to preserve the appearance.
The other problem is the open cockpit. This is a tight fit around the coamings and would have been OK except I had failed to seal the area under the seat. as a result any water in the cockpit drained into the hull - not good. I attach some pictures to give the general idea. More pics will follow as I progress.

Cariad Lead and Keel

The existing ballast consists of 5 pieces of lead and a battery placed inside the hull on the base of the hull. There is a solid keel running the length of the boat but I could not add any weight into this inside the boat. The ballast weighs 4.7kg excluding the battery and clearly would be best placed in or alongside the keel. I propose therefore to make a bolt on lead keel to fit the length of the boat. The existing ballast has 2.9kg forward of the mast and 1.6kg about midships with a small 0.2kg weight in the stern. I will need to keep the ratio the same on the false keel and there is a 1kg difference in port and starboard. By extending the keel down as against making wider I will also increase the sailing stability. On the water the boat will not look any different and the keel will be removed for transportation and when on display. Pictures of the keel and lead weights give the details. I will post more as the work progresses

Rear cockpit and Rudder

Sealed the cockpit with bits of wood and will add silicon sealant round all the joints when the glue has hardened.
Had thought about cutting the rudder post so it was below deck but decided to stick with my original fitting. I have reworked the front and rear coamings around the rudder. When dry I intend to seal with silicon sealant and will cast a silicon plug to seal the gap around the rudder post. When finished I intend to flood the deck with all hatches in place and check for any leakage. I have still to make the silicon seal.

Motor and prop shaft

I had originally arranged for a belt drive to the prop but was not happy with this arrangement as adjustment was difficult. I have now changed to direct drive with a high tork low rev motor - ex equipment so I don't know the provenance but it is low current - stall is 1amp and size is between a 400 and 500 type motor. Our lake is large but as with most sailing vessels there is a tendency for the boat to find the obstacles and the motor helps correct the course when the wind is being unhelpful 😰 Decided to complete this before I commence fitting the lead to the keel below the boat as the new arrangement gives more space and acess inside. Motor now replaced. Final fitting will be completed once tested on the lake.

Lead Keel fitting

I have used a piece of aluminium extrusion I happened to have to make a frame for the lead. This was fitted to the keel with three stainless bolts passed through three brass tubes fitted into the original keel, which is solid fibreglass. I made a very rough mould to fit the aluminium and poured lead into this to create the keel. I have bound the lead to the extrusion with copper wire passed through holes in both at each end and in the middle. Due to the hull shape there is more ballast needed at the prow than the stern so the casting reflects this. Also additional lead was added on the starboard side to balance the battery. Once correctly balanced I intend to cover with glass cloth and resin and make the keel symmetrical with balsa infills. I will also make a balsa fairing to spead the load onto the bulbous forward part of the hull

Keel Fitting - rethink

Progressed this and spent some time making the keel. Worked fine in the test tank and the Yacht is rock steady, the mast is flexing if I push at the top.
However I have several misgivings; the keel is very heavy and the proposed mounting may not be sufficiently strong to withstand the forces experienced on the lake, wind is unpredictable and everything needs to be shipshape to avoid disaster; the sheer size and depth of the keel will make steering unpredictable as the nice clean lines will have been spoilt. 😰
Others have successfully sailed this model with internal ballast and it is possible that I can achieve the same result. Re-reading Philip Vaughn Williams article in Model Boats from a few years ago (vol 48 577) it appears that the full size carried all its ballast in the middle third of the vessel - to allow good seamanship in riding the waves rather than ploughing through. I intend therefore to make a mould of the inside of the hull using balsa fitted to contour and then casting in two pieces, port and starboard. I have a square block for the base of the mast mounting so will use this to key the lead in place. I did favour removing the lead for transport but believe I may have to have it as a permanent fixture. Fortunately I have a suitable carriage to transport to the lake side. 😊

Keel Fitting

Have now fitted 6kg of lead sheet to the base of the hull in small pieces applied each side of the mast support. Decided against casting two single pieces as access is restricted and the sheet follows the contour nicely. I need to test in water and once trimmed I will fix in place , possibly by pouring in polyester resin to cover over. I believe this will be necessary as I do not want any movement whist at sea!
Need to fill up the holes in the keel for the abandonded outer keel.

Rudder post seal

Made the seal in situ with a false base beneath the cover. Used casting silicon as it dries nice and hard. Pleased with the result which has made the rear deck absolutely watertight. I used a small brass screw to hold the cover in place and Improve the seal underneath.

Ballasting complete- motor refitted

Polyester resin now set nicely and all lead very secure in the bottom of the boat. Floatation test shows a slight list which has been corrected with four small lumps of lead seen on the deck but now fixed inside with some silicon bath sealant so I can reposition if required.
Motor now fixed on stand supported with props to the keel and hull side. I have a small brass bracket fixed with two screws to the winch cross members so removal for servicing is easily achieved.
Just need to complete the boat on the deck. Will probably remove when on water, so will fix to deck with rigging rope.
Just need a nice steady wind to test stability. Video to follow, 😀

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