designing a fast rowboat

[Clinton B Chase]

Depth of keel/skeg

Many Faerings have quite a deep outer keel like 1- 1 1/4" and that works back to a skeg that is 1 1/2-2" deep. I realize this is b/c they were sailing these boats often w/o a dagger/center board. My question is, if intend to row my boat 95% of the time with some sailing downwind/reaching on the long tiring rows how deep should my keel be. Similar designs show one as little as 3/4" deep but I have rowed a similar boat to mine that has a keel that tapers from 1"+ to 1 3/4" and it seemed fine. Too much drag? Would have gone faster without? I have drawn a keel that is from about 7/8" fwd to 1 1/4" aft. Would appreciate some thoughts on this matter. Thanks.

Cheers,
Clint

 

[nordvindcrew]

faering keel

Clint,
I've read that faerings the are designed to sail have an even more substancial keel, 3-4" deep. rowing faerings have more in line with what you stated. the deep vee bottom also adds some lateral resistance. For our boat we're thinking of about 1" forward and increasing to 3" aft. We rowed this Sunday with a jury rigged rudder of less than 1 square foot. The results were fantastic! tracked beautifully and balanced against the wind without the stern blowing around. We rowed against a 5-10 knot breeze with no trouble at all and held 5.5 knots easily for as long as we wanted (considering that we're out of shape and need to do a lot of miles this winter to be ready for the first spring race). The rudder worked so well that we may scale down the keel a bit and include a kick-up rudder that is controlled by foot pedals from the aft rowing station. Some of the river races have a lot of very tight turns and a rudder would be a tremendous advantage. It would also help to hold us on course on a windy day. The advantages of keel and or rudder, even with added drag clearly make them well worth while. Where is your project these days? Jeff

 

[charmc]

Clint,
We rowed this Sunday with a jury rigged rudder of less than 1 square foot. The results were fantastic! tracked beautifully and balanced against the wind without the stern blowing around. We rowed against a 5-10 knot breeze with no trouble at all and held 5.5 knots easily for as long as we wanted (considering that we're out of shape and need to do a lot of miles this winter to be ready for the first spring race). The rudder worked so well that we may scale down the keel a bit and include a kick-up rudder that is controlled by foot pedals from the aft rowing station. Jeff

Different style boat, but I've had some experience in kayaks with and without rudders, paddling in open ocean waters. No question even a small rudder, foot operated, is a huge advantage. I never timed one vs the other for absolute speed, but the ease of tracking into head and quartering seas appeared to more than make up for any added drag, not to mention the ability to keep stroking at maximum speed and power while turning. If the class rules allow it, I think it would be a great advantage, particularly in windy conditions.

Again, different boats, but I've noted similar benefits in tracking into seas in canoes. Even a 3/4" narrow keel made a significant improvement in tracking.

 

[nordvindcrew]

improvements

charlie,

Thanks for the confirmation of our thoughts on rudder and keel. They will be added as soon as we can get in my brothers garage to work and have some heat there so we don't freeze. By the way, buddy, what are you doing posting at 1AM? Insommniac like my brother?

 

[Clinton B Chase]

Faering

TX for thoughts on keel...I will look at the drawings again and may add a bit of depth to the keel afterall...I can always shave it later...that is easy.

I am finishing the strongback and making molds next week. Refinishing my dinghy set me back but I should be able to fly now. I plan to "unveil" my boat at the John Gardner Small Craft Weekend in June and do the soonest race after that. I hope to do well with the boat, have a lot of fun in her and look good doing it

I would like to post pics but need to find out how to do that.

Cheers,
Clint

 

[charmc]

Clint,

That much, at least is simple, at least compared to building a boat! . Click the "post reply" button lower left of the last post to get the full version of the post text box. Click the little paper clip icon above the text box and to the right of the smilie face. Click the "browse" button when the submenu appears, and navigate to the picture file you want to upload from your computer. Then click "Upload", close the window, and preview or submit your post and pix.

 

[charmc]

charlie,

By the way, buddy, what are you doing posting at 1AM? Insommniac like my brother?

Some nights I seem to get a second wind and the creative juices start flowing at night. Then there's those goofy guys from Aus and Thailand/Malaysia; can't let their jokes at the expense of us Yanks go unanswered.

I see you've discovered drivel and drivel II (Gamage vs Equadhoo, lately known as Gamage vs Kay9 and the CIA ).

You're hooked, my friend!!

 

[nordvindcrew]

hooked

Yup, definately hooked. Good to find a place with people who are addicted to boats and the water and are all sort of crazy in a good way (usually). Drivel is great as are the joke pages. I'm still struggling with my CAD program trying to master the basics. I've got several interesting hulls drawn but haven't been able to take the next step and get the stations drawn or to do a rendering like Duluth boats does. Hell, I can't even figure out the offsets numbers it generates to loft out one of my creations. The Program is ProSurf, a relatively obscure one, so not too many are familiar with it. If I can get some stations done, I'd like to try a bead and cove strip built boat some time. Right now, I'm accumulating material to build a skin on frame rowing single for myself. It will have laminated white cedar sheer rails so that it will hold its shape when the skin is stretched on. Ribs,White Oak and stringers made of alaskan yellow cedar. covered with either canvas if I cheap out or ballistic nylon if the project looks to warrant it. Traditional construction is with lashed joints, but I think I will use 3M 5200 marine adhesive. Lashed Kayaks are renowned for their flexability, but I think I need greater rigidity in a rowing boat. Probably more like one of Platt Monforts Geodesic boats when it's done. Another consrtuction possibility is to use a single flat head boat rivet at each cross joint. Does anyone have any experience or ideas on this concept?

 

[nordvindcrew]

Faering question

Clint,
Glad to hear that you're making good progress on your faering. I'm curious, what materials are you using for the backbone and planking? In "Wooden Boats book; "planking and fastening" they show a faering being built in what I assume is traditional fashion. It's a very interesting construction method, and looks deceptivly easy. I can only Imagine the perils of someone like me trying to use that method. The Gardner weekend at Mystic is something I've never done, our wooden boats have been rather functional rather than showey or as a display of craftsmanship. The last two we built are FRP, and aren't really in the spirit of the weekend even though they do look rather traditional. Still.... what the heck, maybe just show up and participate. We still have our wood 18' Jersey Skiff and with a bit of a spruce up it would fit in.

 

[Clinton B Chase]

materials

glued lapstrake construction with okoume ply planking and doug fir backbone. I put in one midship frame and will have two half frames (frames are spruce) then either rangs or more likely flotation compartments. How does one decide how big to make the compartments?

Cheers,
Clint

 

[nordvindcrew]

flotation

Decide how much the boat will weigh and how much more you want to support, divide by 64 (weight of salt water), then create a box that is as high as you want the compartment to be, do the math to make the box have the right number of cubic feet, slice it diagonally and you have two units for bow and stern. You'll have to play with the width a bit to make it fit, but that's how I did it. Not exact but close enough if you err on the strong side.

Sounds like Ian Outrights' "Shearwater" sort of construction, will you use battens to support the ply laps?

 

[Clinton B Chase]

Sounds like a good way to get flotation, thanks.

You mean Joel White's Shearwater. yes, she is the primary inspiration but much narrower on the water and longer too bit very much the same idea. Shearwater was reasonable fast, Drake should be much more capable speed wise.

Gartsides, Bob design, in terms of the open water ability was also an influence.

No need to support the laps with battens. Joel White taped the joints on one of his lightly planked boats but Oughtred doesn't ever do anything of the kind on his boats, which tend to be less conservative that Joel White's glued lap designs were. Oughtred's boats have proven there stuff so I feel fine without reinforcement. I be sure that the glue joint is 110% though...8mm garboard and 6mm middle and sheer strake. A midship frame and two half frames and then the flotation inside is the latest addition. Seems smart.

I am trying to come up with an idea to draw for a sailboat, but Iain Oughtred's Caledonia Yawl and Arctic Tern designs are exactly what I need so I have no real reason to draw...partly b/c I know mine won't be nearly as perfected as his..he has had many prototypes and tons of feedback from the raids over in Europe. So I may start drawing a long ocean going canoe for two. Or I may step it up and design a cruising boat.

Cheers
,
Clint

 

[nordvindcrew]

drake

Drake? if it's the name for your new craft, it's a good one and probably very descriptive of the quailties it will have. This speed thing is kind of wierd. Not all that much seperates a fast boat from a slow one. We regularly row against a shearwater, and regularly beat them, but when you look at the numbers, usually only about 1/10th of a knot seperates us. In our fixed seat doubles class, with both livery and work boats included, from first to last place never is more than 1/2 knot. As you see, a pretty small window to work in, and little things make the difference. One of the variables you can't control is the water condition. In some situations, shorter boats can get in between the waves and row over them a lot easier than a longer boat that is pushing through every wave. We're finding out a bit about the wave frequency thing with our 20' boat. It doesn't get down in between the waves and tends to take in a little more water than our 16' boat taken from the same mold with the same freeboard as the longer boat. You've piqued my curiosity again: a longer ocean going canoe? What are the design parameters on that, and what conditions would it b e intended for?

 

[nordvindcrew]

oars again

Back to the subject of oars. I found some carbon fiber oars from, I believe, Sawyer that come in different lengths and have an available blade that looks very conventional. They are intended for white water rafting, and so are probably heavier than necessary. I have no experience with carbon fiber oars, are they fragile? What happens if they get a nick or scratch, does that compromise their integrity? The overall price seems to be reasonable. Melongs advise about light weight oars sure does make sense, and if we need to buy new oars, why not up-grade?

 

[nordvindcrew]

update:New England rowing

several snotty weekends here and rowing has been curtailed a bit. We are getting out on two out of three Sundays but our rows have been rather short. Still no keel on the new boat but a garage door has been installed at my brothers house and we have a kerosene space heater, so work will soon be able to progress. I've ripped up material to laminate the gunnels for a skin on frame boat;final design to be decided between double or transom ended. I'm working outside so progress will be limited by weather, maybe a complete boat by late spring if I don't get discouraged. let's stay connected there are many more ideas to bat around and I hope interest will continue