Trailable canal sailboat?

None of which is untrue but with a waterway about 35 feet wide,there are fairly severe constraints on how much sailing is possible.Something which the OP acknowledges.The height limitations can be a bit unfriendly to lowered masts too.

wet feet said:

None of which is untrue but with a waterway about 35 feet wide,there are fairly severe constraints on how much sailing is possible.Something which the OP acknowledges.The height limitations can be a bit unfriendly to lowered masts too.

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All very true. Sailing in the canals will be under very limited circumstances, if it's allowed at all.

The sailing will be done out side of them. So, if there are bridges to get under, the rig must be very easy to fold down. This likely requirement all but rules ou a tall Bermudan rig.

Rigs, that have worked in the past, are the sprit-peak sail and the Lateen sail.

For getting under bridges the bermudan rig has the big advantage of only two spars to handle. The extra gubbins of a gaff rig complicates things significantly. This may not seem like that big a deal until you graduate to taking bridges on the run.

gggGuest said:

For getting under bridges the bermudan rig has the big advantage of only two spars to handle. The extra gubbins of a gaff rig complicates things significantly. This may not seem like that big a deal until you graduate to taking bridges on the run.

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I don't know about that. In order to get decent sail area (SA), the mast is going to have to be rather tall. And the taller a mast is, the harder it is to set up and take down.

One can lengthen the boom, but then its length gets hard to manage. Also. With a Lateen or a sprit-peak sail, you can get away without a boom. With the Lateen sail, the long yard can be a bit of a hassle, but nothing like a tall mast.

The Thames barges had a jack-line leading from the to of the sprit to the top of the mast. The head of the sail was laced to it, as well as to the mast. The sail was furled much the way a shower curtain was opened, with the use of brail lines. The sprit itself could then fold against the mast, as the mast was eased down.
This was probably of a very ancient design, dating back to Roman times.

sharpii2 said:

I don't know about that. In order to get decent sail area (SA), the mast is going to have to be rather tall. And the taller a mast is, the harder it is to set up and take down.

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Which brings us back to the point I raised much earlier in this thread;a hull narrow enough to fit through seven foot wide locks won't have a huge amount of form stability and the limited depth of water restricts the scope for ballast below the waterline.I notice that we also haven't seen much about the attitude of the controlling body of the British canal system to having boats under sail on their waterways,I doubt that they have a great deal of enthusiasm for the prospect and would advise seeking their views before committing to a build.

gggGuest said:

Maybe a lifting keel boat might work. Its not clear to me whether you want a day boat or something with accomodation. The Q will know more about them than me, but I note the "Kinsman" which is a lifting keel version of the Yeoman keelboat, which is a dayboat, and probably within your dimensions. Don't know what they are like in open water, but I wouldn't want to get caught in serious wind and waves.

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Yeoman and Kinsman are tough old boats we had the nationals in 40+ Mph winds, mind you that was inland.. There used to be a fleet sailing on the sea from Cramond, Edinburgh. Now the main fleets are the Norfolk Broads and Lough Earn in Northern Ireland a not inconsiderable piece of water at 55 square miles..

They are a comparatively dry Boat, due to the big bulge under the mast.
I've been in a knock down in them a few times over the last 20 years of racing them, the standard hull comes up with water round your ankles. That can be solved with either the rare self draining boat, or The later 300 series that just just takes on cups of water.. An early boat can be modified to not take on much water using the seat moulding of the 300 Series. ...
In somewhat calmer conditions I'm in this picture .

they can go under very small bridges and the rig can be brought down in 30 seconds with some preparation and the rig back up again in a minute or two..
There's a yeoman taking it's mast down somewhat slowly in this video..

Oh they can quite easily be sailing in narrow waterways like 35ft, I've done it, it takes practice but it's not a problem tacking up a river that size..

I would be quite happy sailing one round the coast..

Taking down a mast on a gaff rig can be incredibly easy on well designed boat. Like Sharpii2 said the mast can be shorter compared to a bermuda rig with the same sail area. It's the reason gaff rigged boats remained to be popular in Dutch inland waterways with it's many bridges. The example in the video below has a gas strut underdecks which takes even more of the weight off and a smart forestay system. It goes down in 10 seconds.



On calm days it can even be done without taking the sail down.


Edit: picture of same type of boat under sail with it's rig up.

wet feet said:

Which brings us back to the point I raised much earlier in this thread;a hull narrow enough to fit through seven foot wide locks won't have a huge amount of form stability and the limited depth of water restricts the scope for ballast below the waterline.I notice that we also haven't seen much about the attitude of the controlling body of the British canal system to having boats under sail on their waterways,I doubt that they have a great deal of enthusiasm for the prospect and would advise seeking their views before committing to a build.

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I doubt that sailing in the canals will be allowed at all. The original post all but implies this.

There are other ways to get form stability other than greater Beam.
One of which is to have far less curve and taper in the plan view (top view) of the hull.

The part of the hull, that needs taper the most, is the bow. A reasonably sharp bow can have its taper start 1.5 times the Beam, aft the stem head.

The stern needs curve and or taper, at least on one plane. Why not make it on the vertical one?

Now, once the bow taper ends, the sides can run straight back. This taper will have to end somewhat above the water line. But its start can be four of its depths forward of the transom.

The sides can be vertical, or very close to that. The bottom need not be flat, but a flat bottom would yield the most form stability.

The only real problem with this, is that it wouldn't look very "boaty".

It also wouldn't be as efficient as a more normally proportioned boat. But it would likely be efficient enough.

The sail plan need not be tall, to get sufficient area, even with just one mast (two would be best).

With a relatively long run of a nearly straight side, and a relatively narrow Beam, a center board trunk can be right up against the side of the boat, where it would take up minimal interior space.

The sail area need not be huge to be worth while. I have seen S/Ds, ranging from the high single-digits to the high thirties, on workable sailboats, with ones that are from 15 to 20 being the sweet spot.

A goal of having one that is around 15 (at full displacement) may be possible.