designing a fast rowboat

I use drywall joint compound poured into a shallow box and covered with saran wrap. Mix the compound and load the box up with it and lay the saran wrap on top. Gently sit into it but not enough to allow your behind to squish down to the bottom of the box then get up and take a look. When you get it looking ok let the compound cure .

After removing the saran wrap you can sculpt the compound by scraping and also fill any holes with some more compound. Scrape a lot of the center ridge off the seat so it doesn't have an overly intimate relationship with your naughty bits.

Then put the saran wrap back on and cover it with 4 layers of 9oz/yrd fiberglass or the equivalent.

 

What is this "fibreglass" you speak of?

 

Hah! excellent question. And it must be pointed out that a fiberglass seat does not "give" as the torso moves during the rowing. So there is only part of the rowing stroke where the rigid seat is optimized. In contrast, your double-carpet-with-a-core design continuously reforms itself under the contortions of rowing. So best go for that !

 

The Norwegians traditionally use thwarts that rock fore and aft, presumably in an attempt to make it more comfortable when your torso is moving. I have thought of trying it, but haven't got around to it yet. The same thing could be done with fitted seats.

 

back from the dead

Well, 1-1/2 years after an operation for cancer and three heart procedures I'm going to try to get building and rowing again. Just a comment to No Eye Deer, his boat is remarkably similar to the skin on frame boat I built 4 years ago. It rows pretty well, probably better than I am capable of and was reasonably competitive in the races I entered her in. I've tried to get Jon Aborn ( Blackburn Challange master) to try it for his opinion, but it hasn't happened yet. In regards to the seat cushion; I glued up 3 layers of foam from an interlocking floor pad system and carved them out with a coarse pad in my disk sander untill I had a comfortable fit. Not elegant, but comfey. My build goal is a St. Lawrence skiff. I found Anne, and at 20' she looks like a good double for me and my brother. Has any one built and rowed her? I'd appreciate your feed back on her. I've got around 2000 L.F. of western red cedar, 3/8 X 1' that needs to be beaded and coved before I can start. My dream would be to find molds or mold patterns that I could buy rather than do all the lofting. Any ideas?

 

Which Annie is 20'? The Annie I have plans for is at Mystic Seaport and is 17' 9". Is that the one you mean? If so I can provide a file from which a set of molds for strip planking that Annie can be CNC cut. Clint Chase should be able to arrange for the molds to be cut and delivered. It could also be stretched to 20' if desired.

Or do you mean another Saint Lawrence River Skiff such as Bobbie which is slightly over 20' in length? Clint built a strip planked version of Bobbie at Wooden Boat School several years ago. He used molds CNC cut from a file I provided, and he should be able to arrange for another set of molds to be cut and delivered.

For both boats the molds should be also set to go when received with no fairing needed. Both the Annie and Bobbie models are set up for 1/4" strip planking. 3/8" could be used with minor modifications to the stem and keel.

 

Here is another 20 ft St. Lawrence River Skiff from "Forest and Stream" April 25, 1889. The plans and offsets are the same as in John Gardner's book "Building Classic Small Craft".

 

I re-read the chapter about the St. Lawrence Skiff in Gardner's "Building Classic Small Craft" and this is what he wrote about the Colon model (the one from above, post #1897):

 

Anne

Not sure of the designer. I did a search for plans and came up with a boat named Anne at 20' LOA. I'll lool again and post the site if I find it. Thanks for the help.

 

Good for you. Hope you're feeling better now.

TBH this morning was the first time I've taken mine out since Christmas, what with the silly season and several other things. This morning reminded me why I built her.

At the moment the boat is definitely better than I am (which honestly isn't saying much). Her only real fault is that she tends to blow around more than I'd like. It's just a result of having a long, light boat with a flat bottom and reasonable freeboard. They're always going to be a bit vulnerable to wind. Not quite as bad as the Herreshoff/Gardner boat though, going from memory of those, and with better tracking on the whole.

And I think a 20' St Lawrence skiff would be a very nice double for you. They're lovely boats.

 

There is only one Annie and it is a bit under 18', a Bain and Co. Skiff. I have a class teaching how to build SLRS's up at Antique Boat next summer in August.

Bobby is 20 1/2' and is a true double ender. I own a Bobby that my students built at WoodenBoat.

Nord. contact me. I got Skiffs! David and I modeled the two above and the Frye model but only 15'. That 20-footer above looks good but the Bobby molds are ready to go. I might be willing to sell you the hull I have which is ready to be finished out.

 

I've read through this thread a couple times now, and I think I'm ready to throw my hat into the ring. My design doesn't necessarily fit with the original intent of the thread since mine has outriggers, although very minimal ones. But, since there is a lot of guideboat discussion here I think my design fits well. I wanted a guideboat like craft, but suited to solo tripping only, so I ran with that and cut hull surface area as much as possible to cut weight. I wanted the boat to fit in nicely with solo canoes and their method of travel.

The surface area of a Grant Virginia is 58 ft^2 and the John Winters' Osprey I was using as a solo canoe is 47 ft^2. My design comes in at 49 ft^2 so it should come out pretty light.

The hull is symmetrical below the waterline and swede form above to keep the beam for the oar locks as wide as possible.

Thanks Clint and NoEye for the help.

Any criticisms are welcome.

LOA 15'2"
LWL 15'
Beam 35"
Bottom board width 8"
Sheer bow 18"
Sheer amidships 12"
Sheer stern 15"
Hull surface area 49 ft^2
Displacement 3" WL 182 lbs.
Displacement 4" WL 280 lbs.
Beam 3" WL 23"
Beam 4" WL 26"
Cp 3" .575
Cp 4" .590

 

Ben that is looking really good! You've kept the waterlines from going hollow and the stems look very good. With the flat bottom, immersed stem, and the stern acting as skeg, it will be really key to get the trim right in the boat. It is always a challenge. I think about it as I modify my canoe seat in my solo boat. The builders were convinced that I'd be fine; I was convinced that boat trim is really complicated and nothing is certain until many sea trials. So I am making the seat able to slide fore/aft, mostly aft for following wind/sea conditions.

 

Being able to get the boat balanced for-aft is very important with our North American "pro boat" racing canoes (18' 6" long, 27" wide at the 3" waterline). It is easy to tell the difference in both speed and handling with as little as 4" change is seat position. In fact we have sliding footrests that move with the seat. Further, the best balance changes with going from deep to shallow water and some guys do slide their seats during races as the depth changes. The attached pict shows the sliding seat/footrest arrangement.

You might get significant results with a complete rig on rails that has a spring loaded pin lock. Just don't add more than a couple pounds to the total boat weight when you build your slider. My 18'6" solo racer with sliding seat and footrest weighs 23lbs. (vaccume bagged, carbonfiber-nomexhoneycomb-carbonfiber sandwich construction)

http://www.savageriver.com/ (source of pict)
http://www.savageriver.com/canoes/racing/saranac 24ft long racer with good shots of sliders.

I also own the 34lb version of this boat. I have often thought of setting it up for rowing.
https://www.wenonah.com/Canoes.aspx?id=125

A "proboat" carbon-foam-kevlar sandwich. Sliding seats, fixed foot rests.
https://www.wenonah.com/Canoes.aspx?id=137
The little wings are to meet minimum width rules and this sliding seat does not have the sliding foot rest.
https://www.wenonah.com/Canoes.aspx?id=135

 

Thanks Clint. It's really come a long way from my initial drawings. Each change toned it down until I had a good compromise between weight savings and seaworthiness.

John, I looked at marathon canoes a lot during the design for weight saving features. I have a draft with recurve gunwales somewhere on my computer, but it just looked too extreme for what I was going for. Maybe someday I'll take it full circle and build that boat in a vacuumed carbon layup, but my last two boats have been Kevlar and s-glass, and I'm in no hurry to build in that method again. This time I'm going equally strange for the home builder. Two layers of 1.5 mm cold molding with glass outside and Kevlar inside.

I have pondered with the idea of a fully adjustable rig for trim, but I'm not really interested in that complication. I trip in my boats so there is always gear to move around to adjust trim. If I don't have any gear I use the inner bladder from a cubitainer filled with water tied to a rope. A cubitainer is just a plastic bladder that is encased in a cardboard box. It works nice to toss to the back or front of the boat and then pull it closer with the rope until the trim is adjusted how I like it. Since its a flexible bladder it doesn't ever bang up the boat and it sticks where you toss it. It also does double duty for holding drinking water and if empty takes up really no weight or space.

I've also thought of mounting a small bubble level under the gunwale so I can see exactly how I'm trimmed, since it's not always easy to judge while in the boat.