Category: Modern boatbuilding

Modern and plywood boatbuilding and plans

John Welsford starts making sawdust on his Pilgrim cruising dinghy project

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John Welsford cuts out the transom for Pilgrim

It’s always useful to see how the professionals do it, so I’m pleased to link to John Welsford’s diary recording his work on this new cruising dinghy, Pilgrim.

The key points in the latest entry are testing an unknown plywood, including a routine previously unknown to me that involves burying it in mashed potato, marking out using a house-builder’s roofing square (clearly his equivalent of the dry-wall square) and a flexible batten supported by tins of food, and cutting out with an electric saw.

On the latter point, I gather he uses a veneer blade, and I must say the results are impressively free of splintering.

To read the this entry at John’s website, click here.

Airborne lifeboat converted for racing

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‘With a fully battened mainsail, a total sail area of 20sq metres
and two sliding seats, Charles Currey’s converted airborne
lifeboat has an exciting performance. Photo: Charles Currey’

As usual, click on the thumbnail for a larger photo.

I’ve seen a converted airborne lifeboat sailing, but not for some years – so I was intrigued by this photo I found while reading a bound collection of old copies of The Yachtsman. Check the gaff rig, the battened sail and the planks for sitting out – clearly this is a very cool boat.

Are there any boats like this still sailing out there, I wonder?

For more posts on airborne lifeboats, click here.

Two excellent free boat calculators

Sailcalc in operation

Boating enthusiasts love to fiddle with things – for many of us it’s part of the joy of owning and using boats. Some, like me, go further and start to create actual new boat designs, even if we do keep our creations on the small and simple side of the street.

If you’ve tried designing or re-designing a rig, you’ll know that the arithmetic can be tiresome and if you have you’ll be interested in these two calculators developed by one of my friends from the Yahoogroup Boatdesign, Peter Vanderwaart.

The first is Boatcalc, a handy calculator for use with boat hulls modelled using Gregg Carlson’s very useful Chine Hull Developer. See the Boatcalc_documentation. Even if you’re not working on a boat designed using this software, it may be worth reverse-modelling an existing hull in order to make your calculations, and to study its hydrostatics, wetted area and so on.

The second is Sailcalc, a fabulously useful rig calculator that works out centres of effort, sizes and dimensions – from experience, I can tell you that it’s a boon when you’re trying to balanace up the hull of a boat, its skeg and centreboard, and a mast that can only be in one place and a variety of sail options.