Boat rides too high in the water

[paul (lost in france)Participant @paullostinfrance]

To bring my boat down to the designed water line it appears to need ~4kg at the rear to bring it straight. I used 4 of 1 litre water bottles on the deck to test my theory.

So i'm guessing the only thing i can do is fill the bottom up with lead, I'd already braced it up inside to take the load as i assumed I'd need some ballast, just not 4kg!, is there any other options?

Paul

[paul (lost in france)Participant @paullostinfrance]

Is lead the only option?

[ashley needhamParticipant @ashleyneedham69188]

Paul. Sand set in resin, steel strip (building wall tie stuff), concrete.

Bigger batteries.

BUT size for weight and thus keeping the centre of gravity down, lead is your man.

I recently had to weigh a model right doen and purchased lead flasdhing from a roofing company, check out prices on the jolly old `net.

Ashley

[Dave MilbournParticipant @davemilbourn48782]

Paul

Platinum, tungsten, uranium, plutonium, gold, mercury. All are denser than the same volume of lead – although all have what you might consider to be cost and/or handling and/or supply problems…….

Seriously if you need 4kgs of ballast then a dense metal is the obvious choice. Lead is over 11 times as heavy per unit volume as water at 20 degrees C. It can be found (still) at scrap dealers or, if you're lucky, on demolition sites – although the lead and copper are among the first materials salvaged from dead buildings. Lead flashing can be bought from builders merchants. It isn't cheap. **LINK** for a typical UK retail price.

If you don't like the idea of using lead on ecological grounds then steel fishing shot is a reasonable substitute, or even wet sand. Apart from its relatively low density water has the other drawback of being a liquid, so it has to be prevented from sloshing around and upsetting the balance of the boat.

Lateral thinking says why not fit larger batteries? Sealed Lead Acid batteries are a helluva lot cheaper way of buying weight than lead scrap or flashing, and they do useful work instead of just being a dead weight to push around.

Suit yourself.

Dave M

(Sorry for any duplication of thoughts – Ashley posted as I was typing)

Edited By Dave Milbourn on 12/10/2013 16:30:16

[ashley needhamParticipant @ashleyneedham69188]

Duplication, yes and the same points as there is not much alternative. Certainly using big Gel batteries has my vote, weight and extra amps, Winning combination!

Ashley

[Peter FitnessParticipant @peterfitness34857]

Definitely sealed lead acid (Gel) batteries, for the reasons that Dave and Ashley stated, more ballast and longer run time. Several years ago I built a Norfolk Broads Cruiser, similar to the one that Paul T and Bob Abel are building, which needed more ballast to bring it down to the waterline. Instead of lead I used two 4.2ah SLA batteries connected in parallel, thus giving the same voltage but double the run time.

Peter.

[Malcolm FraryParticipant @malcolmfrary95515]

Any chance of moving heavy stuff like batteries to the back? As long as its stable when running, riding a bit high is not a problem – it just represents the boat running with a light load.

[paul (lost in france)Participant @paullostinfrance]

Many thanks for all the comments, never thought of bigger batteries!, there is certainly enough room at the back for large batteries, although I'm not sure how low I can site them yet. Think I'll go for 2 separate cells, one each side, then some lead below them, I've just found around 1kg of lead from old flashing so that plus 2 batteries should be good to go. Also as the model is far from finished there is some additional weight to add yet (but all at the top where i don't want it!)

Many thanks again for the advice

Paul W

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