Fuel Tank, Mast Structure and Galvanizing

This is a hotchpotch of notes on progress we have made in the last few weeks.

I am now focusing my attention on the internal fit-out. We need to get Befur in a state to move her on a trailer to our new home in Cumbria in August, this is adding some needed pressure, to ensure we get everything done in time…

Boiler: As an aside, we have apparently corralled a group of three of us in the SBA who are going to build Yarrow boilers to John King’s design – there is a nice link to a pair of these that were manufactured in New Zealand here….

Steelwork: As regular readers will recall we have decided to build some internal steel-work into the hull to support the Mast (kind of an internal “roll-cage”!). In previous posts I have discussed the start of welding the plasma cut parts together. As you can see below we made a trial install of this assembly into the hull, and then pulled it apart and sent it all off for galvanising…(Quite a scary process involving dipping the parts into a 7m long tank of molten Zinc – very efficiently completed by Wedge Group in Eastleigh) – but now it’s all very shiny!

“Spilling”: One of the skills needed for boat building is how to cut pieces of timber to fit where there are no straight lines (e.g. bulkheads which have to fit inside of the hull and fit round things like stringers etc. The approved technique is called “spilling” and works very well – we mentioned this when discussing the making of the deadwood from “lifts”, but I thought a fuller description might be valuable.

The game plan is simple – first you need to cut a piece of “scrap wood” (e.g. hardboard or off cut of chipboard) which you cut so that it roughly fits where the thing you are making will go. Ideally you need a gap of between a few mm and 6 inches (nice mixed units there!) all around. Then you need a “spilling stick”. This should be about 8″ long and pointed at one end; straight and square at the other end. You then lay this onto the scrap wood with the pointed end resting against the surface you want to have the completed component fit against. Then (while holding the spilling stick still) draw round the end and one side of the stick to record its location on the scrap wood. Repeat this process, moving  the point of the stick all around the surface of the item to be matched to, recording the position of the stick.

Then you remove the scrap wood, and place it on the wood (stock) you are going to use to make the bulkhead or whatever. Then simply replace the spilling stick in each of the locations you marked on the scrap wood, and mark a dot onto the stock where the point of the stick is located. When you are finished, remove the scrap wood, join all the dots (with a flexible batten) and then cut round the line. Done carefully you can get a fit within 1mm or 2mm on even a large bulkhead.

The image below shows the “scrap wood” and “spilling stick” installed to allow us to cut out the floor of the chainlocker. It also shows some of the initial marks. This same process was used to cut all the bulkheads.

 

Fuel Tank, Deck Beams, and Forward Bulkhead:

As Befur’s boiler will be running on Diesel we needed to install a tank. Jay Wolfe provided the tank (a 120 litre one from their standard stainless tank designs) and all the fittings/level gauge etc.

I had installed two bearers (epoxied to the bilge stringers) and fabricated a set of straps and strong backs from 316 stainless (that wrecked three saw blades cutting it – note to self: use the angle grinder next time).

The pictures below show the tank in place beneath the laminated deck beams (which will support the deck). The other picture shows the forward end of the boat with the foredeck beams in place and the bulkhead behind the chain-locker.

Sheerline: Lastly, we have started the work of planing the tops of the hull sides and Deck Clamp to the final lines of the ship, and are now adding additional laminations where the cabin will be, so that we have an (narrow) side deck to allow the crew to get forward easily when mooring or anchoring. (more clamptasticness!)

These addition laminations will also form the “carlins” which will support the cabin sides, so they will need to be finished with a 3-degree inward slope – apparently this will stop the cabin looking like a garden shed mounted on the deck!!!

Adding laminations to the deck clamp to provide a workable side deck, and act as "carlins" to support the cabin sides.

Adding laminations to the deck clamp to provide a workable side deck, and act as “carlins” to support the cabin sides.

 

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