I've been musing on how much lead I'll need to ballast my 1100mm waterline length sailing barge. At a rough estimate, the volume needed to be submerged is about 7,360 ccs which converts to7.36kg. So the all up weight of the boat needs to be 7.36kg too.

Am I right in assuming that if I weigh the completed boat (including rig,battery and all other components), less ballast then the weight needed on the end of the keel will be the difference between that and 7.36kg?

My estimate is based on the beam at the centre (23cm), the depth below the waterline at the centre (4cm) and a guesstimated allowance for the reduced beam at bow and stern (80cm). Obviously the last figure isn't very accurate but I don't think it's hugely in error as the hull is quite boxy with a blunt bow.

btw we had our bath removed and replaced with a shower cubicle last year so I don't have a convenient test tank

Geoff

Edited By Geoff Sleath on 06/11/2014 14:37:57