New Boat Design

[Unregistered]

Hello,
I would be grateful for any comments you could pass on a new dayboat design at
http://www.swallowboats.com/boatb.htm

I have attached a picture here from the website I think, though not sure if it will work...
http://www.swallowboats.com/storm17/corm1sml.jpg

She is 16.5 foot long, and 6 ft 5 ins wide.
Interested to see what people think.
Regards
Matt

[Bob Perry]

It looks beautiful to me.

[Tom Lathrop]

Thirty second opinion.

Pretty boat.

Don''t see point of a double ender except for personal taste.

On a small beach cruiser, the double end stern robs space and makes mounting and storing a small outboard unnecessarily cumbersome.

Fast is relative but I don't see this one as faster than it's brethren.

Not much form stability. It will be tender compared to a hard chine.

Downwind in a blow, it may be squirrely.

Rudder is small and tucked in foul water when running fast.

[SailDesign]

Geez, Tom - don't hit me with those negative waves so early in the morning (afternoon?) ;)
She's a cute little thing, with a shapely stern, and she looks handy. Don't forget, they're designing for Wales, not NC, and the waves are v-e-r-y different there. So the hullform should be different, too. Try looking through the "Working Boats of Britain" by Basil Greenhill, and you'll note that the hullforms are radically different from US local types.
Steve

[Unregistered]

Hello again,
She is a four plank per side boat, (does that make her hard chine? or does hard chine only mean single chine?)
She is also pretty wide, at 6 ft 5" which is above normal for her length, so we believe she will have high form stability.
Agree with you about the double ended bit, she is double ended to make our kits cheaper and easier to build by amateurs as well as for looks. It also makes her easier to row (slightly). But you do lose volume where it would be handy, and you lose any planing ability.
I am keen to hear peoples opinions though, especially Americans as we will be looking to export our kits, with a long term goal of setting up manufacturing there if we can find good people.
Regards
Matt

[gonzo]

The American market is rather small for that kind of boat. I find the rig complicated for a boat so small. It leaves little space for the crew. Is it suppose to be for singlehandling?

[Tom Lathrop]

Form stability is not just a function of beam. It has much more to do with the lateral movement of the center of buoyancy when the boat is heeled. Look at the sectional lines at midships. It is pretty much an arc of a circle. This means that there will be little movement of the CB with heeling and therefore little righting moment, hence I would call it tender rather than stiff. There are other things to consider, like the vertical center of gravity but the initial stability is still low.

Hard chine has nothing to do with whether the boat is lapstrake or whatever kind of construction.

[betelgeuserdude]

Geez, hard crowd. I guess I may be just as kind regarding some cutting edge raceboats. Different strokes, different folks.

Matt, she looks pretty nice. Compares similarly to many successful dories, circa 1900. You might harden up the sections a wee bit, or fit a little ballast either side of the trunk. I like the rig, and the little dodger (anything but blue) just fits. I might be tempted to fit a yoke to the rudderhead and run up to a yoked tiller, forward of the mizzen.

Not too sure how one could make money marketing a kit like this, but rather than rain on your parade, I say give it a go. Then you'll know better than me.

DC

[Unregistered]

Thanks for your comments guys,

Tom, how do you define hard chine? I would say she is a hard chine hull. It has nothing to do with construction method (which is stitch and tape, not lapstrake by the way). She is a three chine hull.
Disagree with you about the stability, though it is all relative. If you compare her to a box then yes, she will be tippy. But she compares favourably with many UK designs, which have similar hull forms but with less waterline beam, and sometimes, more sail. (Take a look at some of Iain Ougtred's designs).

Unfortunately in Europe we have a lot of regulations regarding small boat design called the recreational craft directive.

Actually most of the regs make sense, but it does mean we have to give up a substantial amount of interior space to buoyancy tanks. In our designs we put most of it at the ends, leaving the cockpit for the crew. So the rig really impinges on crew space very little. Much less than an ordinary bermudan with a kicker that garottes you!

One American client has asked us to design it as a Cat-ketch, which we may offer as an option. We have had quite a favourable response from the US via our website, though they are likely to be the wooden boat magazine reading demographic, rather than those more interested in performance.

Thanks for all your comments so far, please keep them coming!

Matt

[Robert Miller]

Just had a look at the lines at your web-site.
Comments above seem unjustifiably tough to me.

Firstly, I think she's lovely.
As to stability, I don't see why she should be less stable than any other approximated round bottom centerboard dinghy. In fact, the large beam to length ratio may make her more able to stand up than some of this type. (None of which generally have the initial stability of hard chine sections.)
I would like to see a deeper more efficient rudder blade, with provision for kick-up when beaching.
Such a boat available as a kit would, in my opinion, find a not insignificant market in the US. There is a sizeable, and growing, population of sailors who would like to build their own boats, feel that they must have a kit to do this, and wish to build out of wood. I have heard of efforts to provide Iain Oughtred's Whilly Boat in a kit form in the states. Unfortunately, this did not come to be. Having the kits produced here should make them less expensive than your present kits which have to be shipped at some expense.
I agree that double enders may provide no real advantage for sailing.... but, to my eye, just look sexy.
Regards,
Robert

[Tom Lathrop]

Hey,

If you only want highly positive replies, I can do that. As I said, she is very pretty. I don't think the rig is complicated or takes up too much room. The unstayed cat ketch is my favorite rig for such boats.

Actually, I thought you might appreciate comments meant as constructive criticism but I'm often wrong. The awkward interference between the tiller, mizzen mast and the mainsheet all in the same place, will go unmentioned. My thirty seconds has expired.

[Unregistered]

I agree with Rober Miller's comments, it is a nice looking boat and should not be excessively tippy but the rudder is vulnerable and possibly ineffective and I would also be sceptical about the ergonomics of the steering, I wonder wether the helmsman might have his arm in a postion which would become uncomfortable after a while.

I thought I would mention a web article I have about a boat I designed for a similar kind of use, although it is smaller at 15' by 5.5' :

http://www.btinternet.com/~sail/boatbuild03.htm

This boat is now quite well proven after about 25 years, when I built it I never really thought that I would still be sailing it for that long. I have sometimes sailed my boat in company with an example of Ian Ottred's Ness Yawl which is a bit like the boat we are discussing although larger. I dont like to brag too much but I can say that my boat has proved to be faster than the Ness Yawl under wind strength from force 0 (rowing) to force 8 (in the Solent not the open sea). But the purpose of a yacht is to please the owner, a large part of that function is a matter of aesthetics and this is a pretty boat.

With regard to the semantics, I always assumed that hard chine meant one chine each side of a vee bottom. If there were more chines you would use the term double chine, or multichine. If you were just making a distinction between a hull with corners and one without corners you would say 'chined hull' as opposed to 'round bilge hull'. I dont know if there are any universally accepted definitions.

[jprev]

She is 16.5 foot long, and 6 ft 5 ins wide.
Interested to see what people think.

Mmmmmmm tough crowd? Might be an understatement. Sort of like President Bush speaking at a military institution... Wait that's not a very good example...

I like the design. Very nice symmetry and balance. Decent space for passengers and gear with adequate freeboard. I also like the funcionality of the unstayed cat ketch rig (although I migh lose the jib). Overall a beautiful little craft that should make a great lake or bay daysailor.

Regards,

Joe

[PAR]

I hate to be an ugly one, but I agree with Tom on the tenderness of this design. She looks to have little ability to carry a press, the tiller is fouled, the rig not overly complex, but the mizzen sheet needs another land. Cute little thing, with some design refinement, could be quite a fine little boat. I'd not like to have to row the thing though (as currently shaped)

[Unregistered]

Thanks again for all your feedback.
PAR, was interested in why you would not like to row her very far? She is obviously primarily a sailing boat, but oars will be important to some people. Am I missing something?

In answer to the other points.
The double ended hull form should generally be fast only in light airs, when other planing shapes can't plane. That has been born out in our own trials here. She is not really about speed, but I am hoping in the right conditions to beat most other cruising designs.

I am concerned about the perception that the rudder is to small. Due to past experience with other completed designs:
www.swallowboats.com/storm-petrel.htm
www.swallowboats.com/sandpiper.htm
I am confident it will be plenty large enough to do anything asked of it.
I think people nowadays are so used to seeing the standard kick up blade rudder they think its the only thing that works. A lot of traditional boats had much smaller rudders than would ever be specified nowadays, but then again, the modern hull form is more directionally unstable and needs a big rudder.
Our hulls have a full length keel about 1.5 inches deep and bilge runners. Running downwind in force 6 or more is fine.
Our mechanism for kick up is a bit agricultural I suspect, but much simpler and less prone to jamming: The stern post is raked and the rudder mounted on a long pin via gudgeons that allow it to slide up this pin when the rudder hits the bottom (thanks to the raked stern post). A manual pull up rope is also intended for rocky bottoms.
Although I am reluctant to change this aspect of the design, I am concerned about the generally conservative buying public who may judge it as some of you have.
But I do agree with you about the main sheet position Tom, in that it could be awkward so close to the tiller. And am concerned about the comfort of the steering position, will have to try and mock it up full size.
We have designed and built a boat with this mizzen/tiller arrangement before:
www.swallowboats.com/gtaphotos.htm
and it proved pretty comfortable, but the boat was narrower there, and so the helmsman was nearer the tiller.
We will be drawing a Cat Ketch rig soon too. It has the one problem of piercing the forward buoyancy chamber though, since there is no jib and the mast must go more forward. If any of you have any bright ideas about how to seal it watertight (and so buoyant), then please let us know!
Thanks again
Matt

[gonzo]

You can put a sealed tube from the deck to the maststep to keep the integrity of the floatation tank. The mast can be inserted in the tube.

[pkoken]

Is it out of the question to simply fill your bouyancy chamber(s) with closed cell foam? This would negate any worries about the mast passing through it, and should also assure that in future these areas remain empty of water.

[Tom Lathrop]

Matt,

I have built and helped others build several cat ketches with foremast tubes that pierce the forward buoyancy tank. The method I developed which is now used by all is to mold a fiberglass tube of slightly larger diameter than the mast. The tube is sealed to the step and deck with epoxy. at the lowest point a large hole is cut through the side of the boat into the mast tube. A piece of flexible plastic tube of about 3/8 inch OD is inserted through the hole and completely encased in epoxy. After the epoxy sets, pull the tube out and chamfer the opening. Self draining and foolproof so far on many boats.

The mast is rotated for easy striking of the sail and for storage.

My thoughts on the other points of sailing qualities remain the same and result partly from experience with Sea Pearls and a few other well known boats of similar type. Off wind in a breeze they grow cranky and are forced to reduce sail while the more stable V bottom hard chine types simply sail away from them under full sail.

Good judgement comes from experience. Experience comes from bad judgement. We each draw from our own experience in the conditions that we sail in and the use we put a boat to. There is room for many solutions to the equation depending on the desired outcome. These are mine and reflect my own biases. They are subject to change if more bad judgement creeps in.