LEAD BALLAST IN DINGHIES

I was interested to read Alan Glanville’s letter in the autumn Bulletin explaining why he carries lead ballast in Lowly Worm, his Ness Yawl, but I fear this has done nothing to persuade me that using metal ballast in dinghies is sensible.

I accept that a big dinghy when sailed single-handed may benefit from extra weight, but why use this valuable carrying capacity just for expensive scrap metal when there are always extra items of heavy gear or stores one would like to have aboard ? Alan didn’t say why he rejected his designer’s advice to fit a 100 lb steel centreboard, which might have put the additional weight low enough to have prevented his capsize. But if he prefers to have internal ballast and wants this low down, why not carry a couple of heavy anchors on chain cables tied down to the floorboards where his lead is now — just as good as the lead for ballast, and potentially life-saving if in trouble on a lee shore? Alternatively, in most boats, a few inches increase in the height of the ballast’s centre of gravity won’t reduce stability significantly, so one can use heavy but bulky stores instead of metal — jerrycans of fresh water or outboard fuel, a keg of beer, a box of tinned food, an inflatable kayak like the Sevylor (as a tender and lifeboat). These items must of course be properly tied down, but have the great advantage of floating or nearly floating when under water so they won’t need big extra buoyancy bags, unlike lead ballast or metal equipment. As Archimedes pointed out, anything under water experiences an upthrust equal to the weight of water it displaces, so since lead is about 11 times as dense as water when Alan’s boat is swamped, his 90 lbs of lead will still be pulling the boat down with over 80 lbs force and will need around 1.3 cu ft of buoyancy bags for support. It’s not surprising that he found his original buoyancy was insufficient! Metal ballast thus adds useless weight and also requires bulky buoyancy bags which waste space; a couple of 5 gallon jerrycans of fuel or water weigh the same and use the same total space but earn this space by being useful. Slade Penoyre