Sunday, 17 April 2011

Completed this year?? - no chance


There really hasn't been a lot of progress over this last winter - due partly to low temperatures and partly to equally low finances. Now at least it's getting warmer but a Robin’s nest has appeared on one of my tool boxes. Last year it was Swallows.

Reading other boat building blogs, I've only rarely seen mention of running out of cash, but the steady drain on financial resources needs to be anticipated by anyone planning this sort of project. I've increased my monthly expenditure from £150 to £200 but this is about at my limit. To make things worse, the costs will clearly increase as the boat nears completion: several steel parts need to be made up and galvanised, and then there will be paints and varnishes, rigging and tackle, sails, trailer, motor, and all that assorted sailing junk beloved of most sailors. I just try not to think about it . . . .

Recent weeks have been devoted to the centreboard case - strengthened to take a considerably heavier 12mm steel centreplate in place of the 9mm ply one shown in the plans. So 12mm sides are used with hardwood reinforcement about the pivot point. The pivot bolt is increased from 12 to 20mm and additionally rests in 28mm bronze bearings set into both the case sides and the centreplate. Before assembling the case, it's as well to make a 12mm ply pattern of the centreplate to ensure its fit and movement. This pattern can also be used to calculate the weight of the eventual steel plate. To do this, weigh the wooden pattern and then weigh, say, a quarter square metre of the same thickness ply: then divide the first weight by the second weight to derive the area of the plate and then its volume. Multiply by the density of mild steel (about 490lbs / cu. ft. or 7.85gms / cc) and, for this boat, you'll get something in the region of 35kg. When vertical (dropped) the plate will be relatively easy to move up through, say, the first 15 degrees or so, but, as it approaches the horizontal, the force on the lifting arm of the plate can be 2 - 3x the plate's weight, depending on the direction of pull. In other words, lifting gear must be used to reduce this about 4 times (two double blocks, one with a becket should do it but a drum winch might be ok). To prevent the raised plate from bouncing up and down a keeper bolt towards the aft end of the case is also advisable.

As can be seen the floor bearers are deep and substantial providing extra support to the case. Additionally, a length of 20 x 75mm floor will be bonded to both the bearers and the case on both sides of the case to form a rigid backbone at this point.
Elsewhere, the extension aft of the foredeck made it seem advisable to build in a stowage locker for anchor, chain, warps, etc. – might look quite nice or might just look silly . . . .

I remain totally absorbed and excited by this project and only dimly recall the days when I had a sort of social life . . . .

Sources

London Stainless Fasteners Ltd. www.londonstainless.com - (great range of nuts, bolts, washers, etc. and you can buy them singly.)

Sitebox. www.thesitebox.com/ (stainless steel bolts).

Fyne Boat Kits UK. www.fyneboatkits.com (kits, plans, wide range of materials, information and advice)

Force4 Chandlery. www.force4.co.uk (marine chandlers)

Selway Fisher. www.selway-fisher.com (marine design, plans, advice)

The Battery Masters. www.batterymasters.co.uk (batteries suitable for marine use)

Classic Marine. www.classicmarine.co.uk (general marine tackle, bronze screws & nails, full range of Oughtred plans).

Robbins Timber. www.robbins.co.uk (large range of timber, fixings, resins)

Sail Register. www.sailregister.co.uk (sails & covers to measure).

Wires.co.uk. http://wires.co.uk (copper wires suitable for stitch & glue construction).

East Coast Fibreglass Supplies. www.ecfibreglasssupplies.co.uk (resins, fillers, matting, brushes, etc.)

Prism Plastics. www.prismplastics.co.uk (plastic washers, spacers, etc.).

Marinestore. http://marinestore.co.uk (general marine chandlers - esp. bronze screws)

Bosun’s Locker. www.bosuns.co.uk (chandlery andmarine brokerage)