Looking for a particular dory design

[Dave Williams]

Any of you folks with a good library know about a design which I think? was called a Boston Dory. It could have been in one of Gardners books or maybe Chapell, but I think Gardner.

It is a Swampscott dory around 28-30ft and was designed for a little diesel far aft. It may have been a power dory.

I have a 30 ft. Swampscott with a schooner rig that I am trying to put a motor in. I am getting to old to rely on just the sculling oar for power.

If anyone out there has access to the books in question and may know about the motor installation I would really appreciate knowing what book it is in.

Thanks to all. Always a pleasure hanging around you folks.

Dave

[ 10-11-2002, 03:06 PM: Message edited by: Dave Williams ]

[Paul Fitzgerald]

The reference you want is Gardners "Building Classic Small Craft" vol 2, pp 144, 145.If you have trouble finding a copy I'll have a go at scanning them and post the plans.

[Dave Williams]

Thanks Paul and rK,

I knew I could count on someone here to have the answer!

Paul if it isn't to much trouble to scan and post that design it would be much appreciated. I am out in the sticks and it's a bit hard to access things. If it looks like I can make that installation work I can order the book. Probably will anyway but in the meantime -

Thanks again,
Dave

[Ian McColgin]

I wish I had drawn when I saw it - maybe someone knows how it's laid out -

Saw a nice OB well in a dory where the hole in the bottom was a bit shorter than might otherwise be needed. The after end slanted, so the well was longer at the bottom than at the top, but what was really cool was that the bracket the motor hung on was on a pivot so when you shipped the motor, the whole unit came up and more into the boat.

Anyway, G'luck

[Steve Paskey]

Dave: Installing an inboard diesel on your dory is likely to require building a substantial skeg. The lines for the power dory depicted in Gardner's book show a bottom that runs back at an angle from midships (in lieu of a skeg), rather than having the usual rocker.

You might also look at the arrangements used on power St. Pierre dories, which are about the same size as your boat.

Ken Hankinson has two St. Pierre dories, and the plans give options for either an inboard or an outboard in a well. You can see drawings of both arrangements here:

www.boatdesigns.com/cgi-bin/store/web_store.cgi?page=stpierredory.html&&car t_id=7186979_6256 (http://www.boatdesigns.com/cgi-bin/store/web_store.cgi?page=stpierredory.html&&cart_id=7186979_6256)

Glen-L also has a St. Pierre dory, but the only power option shown online is an outboard in a well. Go to www.glen-l.com (http://www.glen-l.com) , and look for "Lucky Pierre" in the work boat section of the catalog.

[ 10-11-2002, 11:20 AM: Message edited by: Steve Paskey ]

[Jack Heinlen]

Nice boats Steve. that modified, with the pilot house, looks like something out of Jules Verne novel. Functional chic!

Here's a question about skegs. I've long understood that one of the reasons a dory is such a good sea boat is that there is nothing hanging down below to trip the hull.

[Steve Paskey]

I'm not sure about that, Jack, but it does make sense. Incidentally, the original St. Pierre working dories had a hinged shaft on the prop, so that the prop could be pulled up for beaching.

By the way, there are are more drawings of St. Pierre dories (including that prop arrangement) in Gardner's "Building Classic Small Craft."

Myself, I'm not sure I'd try to hang a new skeg on a big sailing dory unless I had a real good idea, based on someone's experience, as to how it might effect performance. In that respect, an outboard well might make more sense.

[Steve Paskey]

Hello Dave: Forgot to say that I'd love to hear more about your boat. Who built it, and from what lines? Any pictures?

The biggest swampscott-style sailing dory I've seen is the Alpha-Beachcomber type, 21 feet long and narrow. I've sometimes wondered how well a bigger swampscott hull, about the size of the St. Pierre or Boston power dories, would work as a sailing craft.

[Jack Heinlen]

I've wondered some of the same things about the Swampscott hull. Frankly, I was suprised to hear that Gardner had a big one in one his books, but it would seem that scaling up would not cause any problems. Not a great boat to windward, and the rig must be small no matter the size hull, for lack of bearing aft, but being in my middle years I care less and less about that.

Ian will, hopefully, chime in with some thoughts. He has a gunning dory he built.

Regarding the skeg and tripping, I suppose it is a matter of degree. I know of a twenty or twenty one foot power and sail(really just an auxiliary lug rig) Dory by Atkin that has an inboard and a shallow keel. Always looked like a nifty, quick build. A bunch of boat for the money.

Maybe a small saildrive, if such exists. Though it's hard to beat just a bank dory, with a motor in a well, for quick and cheap. Older brother is building one right now, out of foam and glass. A mistake, IMHO, from the point of view of pleasure while building, but when it's done it will be strong, with little hull weight. More for the ballast!

Bring on the halibut! :D

Best,

Jack

[ 10-11-2002, 01:54 PM: Message edited by: Jack Heinlen ]

[Dave Williams]

Wow,

Just came in from the shop for some lunch and found all this info!

I'll have to get back to you all later after giving it some more thought. Thanks!

Here's to kindness,
Dave

p.s.
I don't know how to post photos but I could email some to anyone who thought they could.

[ 10-11-2002, 02:39 PM: Message edited by: Dave Williams ]

[Dave Williams]

Hello again all,

Thanks for considering this question.

Steve, she was built in Port Townsend around 1977 and was abandoned in a field for several years and then local shipwright Martin Mills did quite a bit of work and relaunced. He sailed her for several years she then she was hauled out for several more years till I relaunched her back in June. There is still some work to be done. I think she is a Gardner design which was scaled up and or stretched. The stretching gave some long sweet overhangs and she manages a short chop very well. She has a small cabin, a center cockpit and large stern deck with a small steering well. The rig is a junk rigged schooner and I have become a big fan of the rig. She sails beautifully, points pretty high, tacks like a witch, is mindless to reef and furl the sails. She has a large steel centerboard that I believe weighs neerly 400# with a winch for control. Total displacement has been guessed a 2500 to 3000#. She is very heavily built. If anyone could post pictures from an email it might make all this easier to understand. To my eye she is very pretty!

Jack, I think I could make room for the prop within her draft with the addition of a small skeg but as you mentioned I worry about changing her sailing caracteristics since she is so sweet now. That being said she does have a strong weather helm when she heels down and a skeg might help that. NO?

Ian, she does have a well for an OB now but it is almost midships in the center cockpit and doesn,t work very well. The motor needs to be lifter out when sailing and a plug installed and then where to stow the motor. Also it leaks badly. Rebuilding a different well is maybe an option and I have thought of ideas much like you describe. It would be nicer to have a deisel installation back under the stern deck which is space that is hard to access anyway and get rid of the well altogether, but it,s all up for grabs now. I,m surprised you didn,t try to talk me out of a motor period! I would love that and have sailed her a lot using only the sculling oar which I forgot to mention is a Yuloh and I like it very much. Great for getting in and out of the harbor. It may be inefficiency on my part but I doubt I can get more than a knot out of it and around these parts if the wind quits you had better be wanting to go in the direction of the current!

Well hope some of this makes sense and all thoughts appreciated.

Dave

[Steve Paskey]

Hi Dave: Don't know if you've seen it yet, so I've e-mailed you a scan of Gardner's power dory design. In case you can't read it, the angle of the shaft is 12 degrees.

After seeing at the Gardner plans again, I'm skeptical about whether you could install a diesel very far aft without a large skeg. (I once saw photos of a schooner rigged St. Pierre dory, built to Gardner's lines, and the motorbox was midships in the middle of the cockpit.)

Among the things that need to happen when the motor is installed: the prop must be below the waterline, and the shaft must be at the correct angle. On the dories built for inboard power, there's no rocker, and the draft is deeper at the base of the transom than it is at midships. This allows the motor to sit well aft, with everything aligned as it should be. (On Gardner's design, the shaft exits the boat near the base of the transom.)

In your case, with rocker aft, the shaft will exit through the bottom rather than the transom, and you'll need a skeg to support the shaft until it's far enough below the waterline. You'd also need to think about whether you can position the prop where it doesn't interfere with the rudder.

If you're seriously interested in an inboard, the best way to proceed might be to try to come up with an accurate profile drawing of your boat, showing the bottom, transom, and waterline, then work from that to see how much of a skeg would be necessary for a given prop size.

As for me, I'd stick with the yuloh!

[Jack Heinlen]

Dave,

Here's a link to something worth considering.

http://www.saildrive280.com/

Thinking about the skeg. I doubt a small skeg would affect the boat's seakeeping much. There's that old saw that if you get in real trouble in a dory, just lie down in the bottom and let the boat take care of itself. A skeg would add a bit of bearing aft, and in survival conditions might affect the boats natural riding characteristics, but as you point out it would, in more normal conditions, also ease your weather helm a bit.

Diesel, outboard or saildrive? The outboard sounds complicated by the aft deck you mention, the diesel sounds like a winner except the question about the skeg's problems. That saildrive looks pretty nifty to me. It's gas and probably isn't cheap, but...

Just some thoughts.

Jack

P.S. If it was this kid, given financial considerations(just looked at the price on the saildrive, Phew)I think I'd look around for a small, used, slow turning diesel, install it with a skeg, and go out to dinner for the rest of your days on the money you'd save.

[ 10-12-2002, 06:01 PM: Message edited by: Jack Heinlen ]

[Dave Williams]

Hello folks,

Sorry to take so long to reply. I was away for a few a while.

Steve, I am having trouble opening the attachments that you sent with the email, probably operator error on my part and hopefully SWMBO can help. Thanks. I hear you about keeping the Yuloh. It,s OK if I'm out for several days and have the time to wait and work with the tides but for day sailing it is pretty limiting.

Jack, The saildrive is interesting but you are right it is WAY to much money.

There isn't a lot of rocker I quess because she was stretched. There is roughly 10 in. of draft at the stern waterline (like I said, she is heavy) so I still think it may not require a huge skeg to allow for a inboard installation.

Thanks again! Dave

[Ben Fuller]

I have crawled around in a few old power dories.

Sounds like you are deep enough aft. Need to look at the principles used in inboard power for the old dories. First they used two stroke engines for the most part, which meant that the mounts could be steeper than some modern engines. The hole through the transom should be high enough so that the shaft stays out of the way of the transom, planking and stern knee fastenings. You may need to replace your stern knee if it is the usual narrow one to something that is a combination shaft log / stern knee. Wide enough and high enough to do both jobs.

So start with the engine that you are thinking about and see what kind of angle it will run at. That will tell you where in the boat it needs to be to have the shaft exit the transome a few inches up from the bottom. Then see what the recommend prop looks like, and figure the shaft will have to go out long enough to get it under water. Then you will be able to tell what size skeg you need. Bear in mind that the old power dory skegs were big enought to protect the prop when grounding, and a strap at the base caught the bottom of the rudder which you will also need to rengineer.

When you open the files you were sent you will see that the external skg is really two parts, one runs on the bottom, the other goes vertical like an external stern post.

The St Pierre Dories used a different princple. There the shaft exited the bottom of a well rockered hull perhaps a quarter of the distance forward from the stern. The shaft had a universal joint aft of the bed log which was about flush with the bottom and the prop could be pulled up into a trunk. That was a unit manufactured by the Acadia company and may not work well even if you find one with a modern higher speed diesel.

If you had enough rocker on the boat to be able o get the shaft out through the bottom then you could put on an external skeg/ shaft log the way a skeg built lobsterboat does.

I don't think I would worry about balance. Most dory hulls develop lots of weather helm when heeled and benefit from a skeg as does a rowing dory that does not have to be beached.