The George Blog – Design 055 Stability Test & Comments

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Design 055 Stability Test

Last year one of our Design 055 owners, based in Brittany, France, wrote to say that he had experienced a swamping at sea that he wasn't able to recover from without help.

Now he was sailing the boat somewhat outside the original design brief – but that is how it is – 055 is a very robust and capable open sail boat. She didn't sink, but she was flooded to an extent that he couldn't bail her out because the seas were too heavy.

Design 055 So he proposed to seal off the areas under the foredeck and under the aft deck. Also seal off the areas under the floorboards and make the centrecase much more watertight at the top. We also decided to add 100 kg of permanent internal ballast.

We calculated that this would make the boat much more difficult to swamp, and even under those conditions, it would be possible to bail her out. This is due partly to the extra ballast, so she is more stable to begin with. But principally because when a very large sea lands in the boat, there is less boat for it to fill and more buoyancy to support the water flooding in. So she will float higher and be easier to bail out. And, importantly, the free surface effect of the flood water will be much less.

Having carried out the work over the winter this year, the owner put it to an initial stability test. The first job is to haul the boat down to 90º. That was quite hard to do and took two people to do it. Then once down to 90º, get her if possible down to 110º, which also proved quite hard to to – see the second picture.

The moment the owner let go of the mast, she bobbed upright again very quickly, with about 15cm to 20cm of water in her – easily bailed.

Design 055So far, so good – she is impressively stable. The next test, when the weather warms up a little, is to emulate a swamping out at sea. I am very confident that she will pass this with flying colours too.

We are also incorporating the components for the watertight compartments into the new CNC cutting files for Design 055, which we are preparing at the moment (available in about a couple of weeks), so future 055's will have this modification as part of the standard plans.

I took this to heart in the design of the new EasyBuild 15' day-sailer (Design 155): we have built-in buoyancy under the foredeck and aft deck; and also under the side benches (on 055 there are buoyancy bags under the side benches).

So I'm thinking that the new EasyBuild Design 155 can be pressed beyond her design brief. What's next? - an ocean crossing …

As ever I am impressed by the workmanship and care that went into these modifications. So much great boatbuilding goes on almost unnoticed.

George

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