Monday, July 18, 2011

Fitting Different Rigs to an Existing Boat

One of the great joys of owning and/or building a small wooden sailing boat is that there is plenty of opportunity for experimentation. For some reason it doesn't seem right to go shifting things around on a 'glass production hull, but wooden boats lend themselves to modification. With high-quality epoxy and fastenings, the end result should be as good, or better, than the original work.

I've mentioned previously that rig modification was something which interested me from before I left school. I had been brought up sailing racing boats at the local club, all of which had modern, deck-stepped rigs with lots of stainless-steel fittings and sails full of batten pockets. Although I loved the sailing, I felt the urge to cruise alone in a boat fitted with a more simple, traditional rig such as a standing lugsail.

Phoenix at about age 20 with her original rig
For me, the first real experiment came when I converted the cruising dinghy my Dad had designed and built. She had been constructed with a deck-stepped Bermudan rig just like all of the racing boats I'd sailed. She was (and still is) a fine boat, but I got it into my head that I'd re-rig her with a Chinese Lugsail (a.k.a. Chinese Junk Rig). I spent a long time on the calculations - far too long, I believe - but that was because I didn't really know how accurate I had to be with all of the proportions, and I was particularly concerned about the location of the centre-of-area of the sail in relation to the centre-of-lateral resistance of the boat.
Phoenix showing how well she could get to windward with her Junk Rig. A nice day in tropical North Queensland.

Accelerating out of the tack and heading off hard on the wind. This rig was exceptionally easy to handle, reef, and furl, and has been one of my all-time favourite rigs. I will be making another one sometime...

After the Chinese Lug rig, I fitted the same hull with about four or five other sail configurations, finally settling on the Balance Lug which she currently carries.

When I designed boats such as Phoenix III, First Mate, and Periwinkle (and some others which have not yet been published), I decided from the outset that I would arrange the rig proportions so that several different rigs could be used on the same mast(s) and/or using the same mast step and partners. This results in boats which can be rigged in a number of different ways without having to make any physical alterations to the structure of the boat. I have already spoken about this a little in my post about Phoenix III and the Perfect Customer 

Here are some more photos to illustrate what I mean.
John Shrapnel's Periwinkle showing her standard Cat Ketch (Periauger) rig. Crew weight is a little far aft, but she is going nicely. This boat is very fine up for'ard, and needs to have weight kept out of the bow when pressed.
Same boat, but with the mizzen removed and the mainmast and mainsail moved aft to another mast step and partner. The rig is still perfectly well balanced, even though the 51sq ft mizzen has been removed entirely.
Here she is with just the mainsail up, stepped in the middle location, but with a substantial reef tied in. It may look calm in the little bay, but it was blowing outside on the more open water.
When it really starts to blow, or when the crew weight is low, you can set the mizzen in the central location. Once again the hull balance is fine, but the rig has been reduced to a snug 51 sq.ft. Even so, when this picture was taken, the boat was doing 8 knots by GPS! If you needed to , even this sail can be reefed.
This shows you the rig combinations on paper. Note how well the centres-of-area cluster near the centre-of-lateral resistance of the hull in all combinations. The key to this was careful proportioning of the sails and the mast locations.
This is another rig which can be used on the boat. The little flying jib is optional, but will help her a lot and will stand ok without shrouds or backstays. The gaff-headed cat rig is set on exactly the same mainmast as in the standard rig, so there is no alteration required to any part of the boat. This print is of an early sketch and some elements are not shown.
...and her you can see Graham Faulkner's Periwinkle with the Gaff-Cat rig, beachcruising on Fraser Island, Queensland, Australia (this was the second boat built, and Graham even made his own sail!)
This shows the three mast locations - the mainmast partners in the lower/left of the photo, the central position through the main thwart, and the mizzen partner through the stern sheets (aft thwart)
All of that thinking made me very tired! Actually, that is just me showing the comfortable sleeping position on either side of the centreboard case.
Build yourself a wooden boat, and then try some rig experiments - it is great fun.

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