De­sign­ing a steel sloop

Mike Camp charts the tri­als and tribu­la­tions of de­sign­ing and build­ing his 26ft steel sloop

Practical Boat Owner - - Contents -

The tri­als and tribu­la­tions of de­sign­ing and build­ing in steel

About 50 years ago I had the op­por­tu­nity to work in the shop of Tom Colvin when he was at Ch­e­sa­peake Bay. Tom was one of the first boat­builders and de­sign­ers to ad­vo­cate the ad­van­tages of build­ing cruis­ing sail­boats in the 30ft to 50ft range out of steel and alu­minium. His book on build­ing with these ma­te­ri­als is con­sid­ered the bi­ble of con­struc­tion man­u­als.

His de­signs were also known for be­ing based on the whole­some and prac­ti­cal ideas of work­ing boats of the past. Over the fol­low­ing 30 years I worked on and off in many shops build­ing and do­ing re­pairs in wood, fi­bre­glass, steel, and alu­minium, mostly on the west coast of Bri­tish Columbia. Also dur­ing these years I owned two sail­boats. The first was the 27ft Even­tide de­sign by Mau­rice Grif­fiths, my sec­ond favourite de­signer. The next was a fac­tory fi­bre­glass pro­duc­tion boat called the Pa­cific 30. In ad­di­tion I sailed on boats of friends when­ever I could. This was all coastal sail­ing, never off­shore.

Then about 20 years ago I de­cided it might be time to start think­ing about build­ing a boat my­self. But which de­sign? There are so many to choose from. I loved Tom Colvin’s Chi­nese Junk de­signs. I ac­tu­ally pur­chased a set of plans for his 42ft Junk, but then wisely de­cided a 42ft heavy dis­place­ment boat was way big­ger than I needed or could af­ford. The most com­mon mis­take of peo­ple buy­ing or build­ing a boat is de­cid­ing on one too large.

I also was at­tracted to the tra­di­tional ‘Tahiti Ketch’, as well as some of Mau­rice Grif­fiths’ de­signs in the 30ft range.

Af­ter much con­sid­er­a­tion, and with all my boat­build­ing and sail­ing ex­pe­ri­ence, I de­cided, why not de­sign my own boat? So work be­gan, even though my wife is say­ing I’m al­ways try­ing to rein­vent the wheel. In re­ply I keep telling her the wheel is not nec­es­sar­ily per­fect.

My first de­sign was a 32ft cat schooner, dou­ble chine steel with bilge keels. A half-model was carved, the lines taken off it, and then these lines lofted full size.

Well, af­ter I’d fab­ri­cated that long, steel keel I re­al­ized I didn’t have the time or money to fin­ish such a large boat. Tom’s 42ft Junk dis­placed 35,000lb. This boat dis­placed about 18,000lb – still too big.

So… back to the draw­ing board. Time to make some hard de­ci­sions. How small could a steel boat be to carry a cou­ple in safety and rea­son­able com­fort… and cross an ocean? The de­sign I came up with was dou­ble chine steel with bilge keels, sloop rigged, with the dinghy car­ried on davits off the stern, 26ft on deck with a dis­place­ment of 8,600lb.

A per­fect size?

A boat of about 26ft has many ad­van­tages. You can get by with­out an an­chor winch, or any sail-tend­ing winches. And for aux­il­iary power, an out­board works very well, thank you. Of my two pre­vi­ous boats one had out­board power, and one in­board. The out­board was a far bet­ter ar­range­ment in ev­ery way – no through-hull fit­tings, which are al­ways a source of leaks, no noise and smell in the in­te­rior, and all of that great stor­age area opened up in a small boat with­out an in­board. And to­day’s 9.9hp 4-stroke out­boards are ri­valling small diesels in fuel econ­omy and they are much qui­eter. Plus, for ser­vice or re­pairs the engine is taken to the me­chanic, and not the other way around. Guess which is cheaper?

Also, when com­par­ing dif­fer­ent de­signs, the two most telling fea­tures of a boat’s size are wa­ter­line length and dis­place­ment.

One of the most com­mon tricks of the modern de­signer is to ex­tend the bow and stern for no rea­son other than to make a boat seem big­ger – to turn, say, a 30-footer into a 36ft boat so the de­sign­ers and builders can charge more. In my opin­ion this ar­bi­trary length­en­ing of a de­sign adds noth­ing to sea­wor­thi­ness, but it does make a big dif­fer­ence in dock­ing fees. But, of course, most de­sign­ers can’t be con­cerned with any­thing so mun­dane as the cost of keep­ing one of their boats at a dock.

Then there is the thorny is­sue of the dinghy. Some sailors like to keep it over­turned on deck, but then it con­stantly blocks your vi­sion and is in the way when tend­ing sails. The best route, I think, is to keep it on per­ma­nent davits, big-boat style. Mostly out of the way, but still read­ily ac­ces­si­ble. The only down­side is some mari­nas are go­ing to charge you that ex­tra 4ft boat length. In this case, you just have to bite the bul­let and live with it. And as far as dinghy ma­te­ri­als go, my first hand­made one of fi­bre­glass over ply­wood rot­ted out be­fore I had a chance to use it. My next dinghy will be made ei­ther of solid fi­bre­glass or will be an in­flat­able.

The last fea­ture we will talk about is life­lines. On a wooden or fi­bre­glass boat it’s just about im­pos­si­ble to make them strong enough to with­stand the force of a 200lb man (or woman) be­ing thrown vi­o­lently against them. On a boat made of alu­minium or steel this is pos­si­ble, but then they are usu­ally made at just the right height to flip you over­board when thrown against it. To say noth­ing of the con­stant has­sle get­ting over them while docked. No, for me, I much pre­fer a su­per solid toe rail, and cabin top handrails. If your feet stay on the deck, and your hand is tight on a deck rail, it’s im­pos­si­ble to get tossed off the ship. Hav­ing said that, in rough weather an over­board line at­tached to each crew mem­ber is al­ways a good idea when leav­ing the cock­pit.

So how did we ar­rive at the ac­tual hull shape? Well, the afore­men­tioned 32ft cat-rigged Raven Lady de­sign was ob­tained by carv­ing a half-model and tak­ing the di­men­sions of the model. I felt too lazy to go through that ex­er­cise again, so I de­cided to cheat. The 26ft Lynx has the same keel shape, stern pro­file, tran­som lines, and mid­ship frame de­sign. So I fab­ri­cated the short­ened keel, set up the stern and tran­som pieces, and welded the mid­ship frame in place. Then I sim­ply bent the shear bar, up­per chine bar, and lower chine bar in place, and the hull shape was es­tab­lished. I call this process ‘loft­ing-in­place’ – although there may be a proper name for it. There were no real prob­lems en­coun­tered in plat­ing this frame­work.

So then there is the cabin and cock­pit de­sign and con­struc­tion ma­te­ri­als. Where two dif­fer­ent ma­te­ri­als are joined to­gether is al­ways a source of fu­ture prob­lems. I se­ri­ously con­sid­ered an all-steel top­side but con­cluded that would cre­ate too much weight aloft. So the de­ci­sion was made to use lam­i­nated ply­wood cov­ered with fi­bre­glass cloth and resin. Over­all it worked out well.

Choos­ing a rig

The orig­i­nal rig for Lynx was go­ing to be a cat rig. That is, one mast stepped right close to the bow, one large sail usu­ally gaff rigged, with no stand­ing rig­ging. These boats were built by poor fish­er­men who de­signed out all un­nec­es­sary ex­pen­sive fit­tings and gad­gets – ex­actly op­po­site of the modern trend.

Any­way, I fab­ri­cated the mast step, and the boom. When I had a look at that huge

‘My wife says I’m al­ways try­ing to rein­vent the wheel. I keep telling her the wheel is not nec­es­sar­ily per­fect’

boom and imag­ined it sweep­ing across the cock­pit in heavy weather, I chick­ened out. So I went with a tra­di­tional sloop rig with a large main­sail and a nonover­lap­ping jib for easy tack­ing. I made a jib boom and boom track, but it was more trou­ble than it was worth, so I went back to a loose-footed jib. If the boat ever gets off­shore, I would ac­quire a large, over­lap­ping jib.

And a quick word on built-in tanks: don’t have any! In my years do­ing boat re­pairs, it wasn’t a ques­tion of if they would be a prob­lem, but when. Even­tu­ally both wa­ter and fuel tanks will be­come con­tam­i­nated and will need to be cleaned out. And de­sign­ers and builders never put large enough clean out open­ings. And then the lines and fit­tings al­ways even­tu­ally leak. In the bilge un­der the floor of the Lynx I have enough room for at least 100 two-litre bot­tles of wa­ter, prob­a­bly more. The gas cylin­der for the out­board is on the same stern plat­form as the engine, and ex­tra gas cylin­ders are car­ried in the cock­pit seat lock­ers, which are sealed off from the rest of the liv­ing area so there is never a smell of gas in the cabin.

Speak­ing of the cabin in­te­rior, the four berths of my orig­i­nal draw­ing were re­duced to two, which gives way more stor­age ca­pac­ity. There is a propane gas stove, and a per­ma­nent wood stove. Don’t laugh un­til you’ve tried it. Propane heat­ing stoves are great for cre­at­ing mois­ture, some­thing we are try­ing to avoid on a boat if at all pos­si­ble. There is a toilet with a hold­ing tank.

And a fi­nal word about over­all boat aes­thet­ics: ev­ery­one likes a boat with pleas­ing lines, but the shorter the over­all length, the harder this is to do. It took a lot of ex­tra work to at­tempt to get nice, flow­ing lines in the deck and hull, but I think it was worth it. Must be my artis­tic back­ground. But then you can be the judge of that your­self. As far as the un­usual shape of the bow is con­cerned, the best an­swer I can give is that it just turned out that way. I know it is usu­ally long and nar­row but as the beam still ex­pands rapidly to 10 feet, it doesn’t seem to have hurt the in­te­rior ac­com­mo­da­tion. It parts the seas won­der­fully well and re­sults in pretty much zero wake which adds to the over­all ef­fi­ciency of the de­sign.

And the name Lynx? Dur­ing my years as a pro­fes­sional trap­per in north­ern Canada, it was my favourite wild an­i­mal. Ac­tu­ally, it still is.

Orig­i­nally planned for a cat rig, Lynx wound up as a sloop

Lynx on a pon­toon moor­ing on Lake Temagami, On­tario

ABOVE Mike Camp’s de­sign for his 26ft steel con­struc­tion yacht Lynx

ABOVE Hull shape is es­tab­lished once keel, frames and chines are in place LEFT Plat­ing of the hull is un­der way

Top­sides are con­structed from ply cov­ered with glass­fi­bre cloth and resin

Mike in full weld­ing kit at work plat­ing the bow of Lynx

Func­tional down be­low. Note wood­burn­ing stove and stain­less steel com­pres­sion post

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