Sailing Dory build with Clark Craft plans

I'm new here, this is only my second thread. To prevent from taking over the first thread I moved here.

I have over 20 years experience as a Tool & Die maker, Machinist, CNC programmer/Operator. I also have Auto CAD and CAD/CAM experience. I have been building wood projects for the last year. I perform at living history events as a 1720's Pirate.

I have decided to build a 18' Sailing Dory with Clark Craft plans to use at some of these events. This will be my first boat. I chose the Dory so five or six of us can use it at a time, its stability and ease of construction. It will be primarily oar powered with the mast (s) added later. 1/2" side and a 3/4" bottom.

Has anyone here used Clark Craft plans before?

I was going to use SS screws or Slicone Bronze to hold everything together. Screws will be left in. I was going to apply a layer of fiberglass cloth and two coats of epoxy to the exterior hull. Inside and out with epoxy paint. This way, I could use construction grade PW. If I use the more expensive Marine PW I can forego the full fiberglass and epoxy treatment. I don't care if it only last 5 or 6 years.

The boat would be used maybe a dozen times a year in bays and harbors in coastal SC. It will be kept in a shed when not in use.

I came here BEFORE I started to do research and get advice to prevent wasting materials and money.

 

Dory

I can share some advice. I design and build boats professionally. I just completed a dory design for a customer who starts building it this week. There are more ways to construct a dory than any other boat, which is part of the fun.

If I were to spend 200+ hours building a dory, I would not use anything but marine grade PW. You can do less glassing overall with a PW like Meranti and that is fairly affordable wood. Doug Fir marine ply is not that much cheaper, most people spend a couple extra bucks a sheet and get the Meranti. You still want to glass the bottom and I would glass the garboard on my boat, inside and out if it were going to get a lot of use. Runners on the bottom of a hardwood is a good idea, maybe from a couple feet forward of centerboard case all the way aft, tapering off at the ends. By all means use screws and keep them in the boat. SB is a lot more expensive than SS. Your choice.

Attached is my dory rendering.

 

I seem to be heading towards marine PW. What do you think about using red oak for the framing and other triming?

 

Red oak is fine on a lightly used boat, especially if sailed in salt water, which tends to act as a preservative. On the other hand, white oak is a superb boat wood--- strong and rot resistant, and you should be able to get it without too much trouble, at maybe a dollar more per foot.

 

Pirate Lowe, if this is the same dory, you still don't need oak for the structural elements and it'll just make the boat heavier then it needs to be. Considering your build, I'd use the 2x10's and 2x12's from Lowe's/Depot and rip them down, to the sizes you need. These larger pieces of framing stock will be from older trees with far fewer defects.

I wouldn't use red oak in a trailer sailed boat. Red oak is the weak knee, redheaded step child to white oak and it's only real marine use is constant immersion in salt water or used a decorative trim. The Lowe's/Depot framing pine will do just fine for your boat, forget about the fancy hardwoods and save yourself some money (lots).

 

Yep same dory. Thanks for the advise. Plenty of pine and poplar at my Lowes. Like the idea of ripping the larger boards. Sounds like a plan. Once I kick off this project in a few weeks, I'll post pics and updates and need shoulders to cry on as I try to complete my first boat project. LoL

 

I don't disagree with PAR that red oak is heavy. My recommendation was primarily based on fastener-holding, which isn't very good with pine (though pine works well where epoxy is relied on for most of the holding power).
Oak, even red oak, is going to hold screws well.
Poplar, especially what's found in the box stores, is a brittle and rot-prone wood, and yes, I've heard some species of poplar might find some limited use on a boat, but why take chances?
Southern yellow pine is reasonably light and especially rot-resistant, as to a lesser extent is fir, and as said, pine is a good boat wood. When I use a soft wood for framing, I drop a little polyurethane glue (Gorilla) into the screw hole. I'd imagine Titebond III would do as well---hardening the screw hole so the screw thinks it's buried in a harder wood.

 

The plans call for 1/4" bolts to be used to hold the frame sections together until the epoxy sets. They call for a butt joint but I plan to notch them both and then bolt and epoxy them. The keelson calls for two bolts per frame member. I'm going to epoxy everything. Glass and epoxy resin on all the seams should keep the bay out and the dry in. GOod stiff frame.

I kind of figure when I coat the frames with epoxy and run the SS screws through the PW, some epoxy should transfer and travel into the frame on the threads. [fingers crossed]

This will be a fair weather, calm water boat with limited use, so I'm not afraid to use construction materials. I can always use this one and make my second boat a fine keeper!

 

I'm not afraid of heavy, I thought the Dory would be more stable when it was heavy anyway. I'm going to trailer it so I don't care if its a little heavy. Plans say 250 to 300 pounds with recommended materials.

 

I received my Dory plans today. Wow, full size prints. They are copy righted from P.W. Blandford Associate of the Royal Institution of Naval Architects.

This Dory gets a frame that is comprised of a Stem a Transom and five frame sections. These are mounted to the floor of the work shop by means of screws and battens across the top of the frame assembly. They are about 12 inches longer than finished dimensions.

Chines, stiffeners, risers and gunwales mount to the frames with screws and glue. In this plan, the PW skin is screwed and glued to the chines, stiffeners, risers and gunwales and there is a space left between the frame and the PW skin. Seems like this design will "flex" more than the other designs I have researched over the last few weeks where the PW is attached directly to the frames and the chines are made flush with the frames. One advantage I see is allowing any water in the bilge to move freely along the bottom and not gather in sections. On the other hand, there is more wood in this frame than the others also. It also calls for 5/16 marine PW. I figured on using 1/2 or so.
This will be a great experience for me as these plans use proper names for all the items so I will get a good education about what all the parts are called.

I'll keep posting in here as I progress and post some pictures as I can also.

 

Do NOT change the planking scantlings to 1/2" plywood, from 5/16". You'll double the weight of the planking, which is an ability killer in a small boat.

This boat isn't more "flexible" then other designs, the plywood will make the frame structure very rigid. Finding 5/16" plywood will be very difficult, you have a few options, but only one good one. Use 6 mm (1/4") plywood and sheath the exterior with 8 ounce biax. This will give you the same strength as 5/16" plywood, with a lot more abrasion resistance.

This particular boat is a copy of a well known American craft and is designed to be fairly light weight. If you want a heavy duty version the plans may offer some suggestions (don't hold your breath), but don't take this task to your own hand. Over building this type of dory is like putting a 4 cylinder in a Corvette.

 

You are right. I failed to consider the surface area. Five frames 1 1/2" wide attached to the PW from gunwale to gunwale is less area than the 2 7/8" wide planks running lengthwise of the hull. This will make for a very rigid hull.

Can I tweak the lumber sizes for the frame?

Here is my dilemma. I am on a super tight budget. This is why I wanted to get as much as possible from Lowes since I have a card there.

If money were no object, I'd order the called for materials and go for it.

The plan calls for 2 7/8 x 7/8 for the frames. If I used 1 1/4 x 4 this would give me a 1 x 3 1/2 frame. I would prefer to go a tad bigger/heavier than smaller like using a 1"x3". This would make it heavier, yes, but I would avoid a ton of waste ripping down larger lumber.

 

Most of the time you can mill your stock from larger pieces. Like getting 1x2's (.75" x 1.5") by ripping the edge of a 2x4 (1.5" x 3.5") down at .75". Saw kerf waste can be minimized to a degree, but there's going to be some. You'll be lucky if you can keep you waste below 20% as a novice builder. On a boat the size of yours, this isn't a lot of material. Plywood waste can be higher, mostly because of the weird shapes you'll be cutting out of it, but with careful planning (there's the rub) you can keep this to a minimum too.

One of the problems with older plans and plans from over seas is they don't dimension stock to handy sizes. For example, I would build those frames from 1x4's (.75" x 3.5") and rip them down the one edge to 3" (not 2 7/8"). This would help to some degree mitigate the slightly smaller dimension on the one side and you could put some shape (taper) into them if desired, which looks good.

Do not be caught in the common beginner's trap of building it "a little bigger here, a little bigger there . . .". This more often then not, doesn't make the boat stronger, but actually makes it weaker, because you've raised point loading, stress risers, moment of gyration and mass to some structural elements, without regard to the other elements. In other words, because you've made a part bigger only insures it will have more mass (and area and volume). Which in turn may (for example) not flex as much as the smaller part it replaces, which bears against it's neighbor with more force, causing it to break prematurely or unexpectedly. All because you elected to "make it stronger".

Build your frames out of 1 by stock, ripped from say a 1x6 or 1x8 which will get you two futtocks (frame pieces) from the price of one stick. Cutting like this will also permit you to use flat sawn stock, but have quarter sawn futtocks when assembled.

 

Makes sense. I've got Auto CAD on my laptop and desktop so I've already laid out my plywood sheets and arranged the parts to optimize my cutting and minimize waste on the small parts there. Sounds like a plan, rip the board and after the kerf, I'm close to what I want. I can use the bandsaw to add some taper. I'll finish all the frames with a nice radius and blend to the gunwales.

I was trying to err on an 1/8 thicker material rather than under. I can see the trap, make it bigger and stronger and then it won't float! LoL

The plan calls for the frames to be screwed to the workshop floor. My shop is not large enough to do that. 18' x 6' boat and a 10' x 20' shop with a 4' door. I can build it in there, but then I can't walk around it.

So, I plan to put 3 or 4 treated 4 x 4's down in cement beside the shop and build a solid and square frame work that I can mount the frames to and simulate the shop floor. I can make it a little higher, I'm 6' 4" so taller would be better. One of my Pirate friends has expressed interest in making a Dory also.

After the sides are skinned, I can remove it from the frame work and finish it on saw horses in the shop if weather prevents working outside. I can cover it with a tarp when I'm not working on it.

 

Rather then use the PT 4x4's, build a 2x6 box with a few cross pieces to help hold it square and keep it strong. Attach the frames to this, which will serve as a firm base and later can have wheels on it to roll around. You can also use it to help hold it up to a nice working height, when you roll the boat over. If you need it to roll, just to have the room in the shop, make it stout with plywood gussets in the corners to keep it from wracking.