Back to Top

Category: Articles from The Log

How Much Bouyancy is Enough

HOW MUCH BOYANCY IS ENOUGH?

This is the (only) Golden Bay 11 (normally they are 12 ft but this one was shrunk to fit davits)… she sails and rows and motors well even with up to 5 adults on board. A good all round tender dingy but with buoyancy confined to forepeak and rear thwart.

One day, solo, with a bit much breeze it capsized while trying to run square. She floated low in the water and proved impossible to bail out and/or re-enter. So something had to be done.

 

With respect to how much buoyancy is enough, the plan was to have about 80-90kg of buoyancy in each side tank (including the part of the existing seat tanks in bow and stern-that could be considered an extension of the side tank). The boat weighed a little under 60 kg before, and the estimate was it would add 5-10kg with the new tanks.

How did it turn out?

Looks like the side tanks are just right. The port tank is just above the capsized waterline. A minimum of water spills over the tank and enters the foot well. The water that comes up with it is confined to the middle of the boat and actually acts as ballast and so adds to stability, making it easier to get in.

HEAVY LIFTING

When we turned Lyle’s NIS 18, he had a chain block connected to a temporary pivot point at each end of the boat. The attached diagram of a Chinese windless is a do-it-yourself alternative to the chain block for heavy lifting. Also, there is a diagram of how a chain block works, in case that has been a mystery for you. Both diagrams come from the book Self Sufficiency in the Eighties by Mario & Lesley Zolin published by Allen & Unwin in 1983.

 

Editor’s Notes.

Don’t forget to check if your carport/garage roof truss is strong enough. You are generally OK with wooden trusses but some modern structures use thin steel channels which do hold the roof up but are prone to buckling when loaded in a way not considered by the designer. (Like a rope chucked over a beam). Over the years I have collected several mainsheet systems which consist of 3 or 4 purchases… some with cam cleats, some without. I attach one to the stem of the boat and one each to the transom corners. That way I can pitch and roll the hull every which way to work on inaccessible places details and even roll it right over. I find this type of system works even if you don’t have enough pulleys and rely on purchases running through a big shackle. Some skill in knot tying is required when you don’t have a cleat. Just use the Midshipmans Hitch Or Tautline Hitch to tie the tail back on one of the purchases.

This is a remarkably useful knot. It is adjustable AND trustworthy. Each sailor should know how to tie this knot in any circumstance. Especially to tie himself to a rescue rope thrown to him in the water. Anyone who uses a tent should know this knot. It is the best way to adjust your lines to the tent-poles. It is the most simple of the adjustable knot family.