designing a fast rowboat

Drake

Yes it's a little light. I am 6'6" and 200lbs and with my gear I am definitely at the waterline.

The St Lawrence River Skiffs would be up your alley. The Annie would be a good match.

 

Heavy

What you don't want is a 250 Lbs varnished wooden beamy lapstrake boat.

 

Drake is about 100-110 lbs if its done right. My race boat will be lighter. Drake has a wonderful manner in choppy conditions, just maintaining headway through the chop, upwind too.

 

Any regs for open water fixed seat?

Hi,

I'm in the process of designing an single, open water, fixed seat, row boat. Currently it's 18' loa, 17' lwl, 3.5' boa, 2.5' bwl, and 1.25 depth amidships. I'm 5'-8" and 175 #, and I'm aiming for an on the water displacement of under 300#, dripping wet, w/me and gear.

My questions are whether there are any regulations imposed by race organizers concerning the amount of decking and sealed compartments I can use, bilge pumps and powering, and whether I'm allowed to carry any water ballast, and if so can I ship and discharge it at will?

Thanks,

Rob

 

most races have rather relaxed rules, a fixed seat and no out riggers, being the biggest things looked for, to enter the fixed single class. some races divide between work boats (dories) and livery (most everything else). I showed up at the essex river race one year with a fixed double with out riggers, we got stuck in the unlimited class, with no direct competition...
Water ballast, decking, rudders are all allowed, but since they add weight, most racers won't have them, unless the conditions are really blowing.

 

The water ballast is an option, otherwise a floatation tank ;-)

The decking, I'd work into the design as a structural element, and I want the boat to be self rescuing.

Rob

 

Another question. How would sponsons fare in the eyes of race organizers in a fixed seat, oarlocks on the gunwale class? I assume they'd get by on an Old Town Otca set up to row, but something racier?

Thanks,

Rob

 

Too Narrow

A typical canoe has a 36" beam and is too narrow for oarlocks on the gunwales.
A drop-in rowing rig has outriggers and a sliding seat.
The sliding seat lengthens the stroke and gives more of a full-body exercise.
I cruise at about 15 strokes per minute, half of a racing cadence.
Rowing oars are flat-sided (square) where they rest in the oarlocks to make feathering positive and reliable.
Oar blades have a lot of air speed during the back stroke, and feathering makes a performance difference.

 

Thanks Rowerboat, maybe you misunderstood where I was going in this line of inquiry, I'll try to be obscure more clearly.

I'm looking at different strategies for a fast single fixed seat, no outriggers, rowboat. Pushing the wl beam narrower for a given displacement seems to be the most effective direction in increasing speed, but at the expense of stability and a reasonable oarlock spread. A concave flare in the topsides helps get a better spread but doesn't do much for stability, hence the interest in sponsons.

I guess what I'm trying to establish are the limits in hull parameters for this design spec.

Thanks,

Rob

 

I do not believe that you would have any trouble racing in a fixed seat class with sponsons. The various groups that put on these events are pretty loose on class rules. You need the oarlocks on the gunwales, a life jacket and a whistle. Usually they ask you what class you consider yourself. The one exception might be the Blackburn Challenge and the Cape Ann Rowing Club. They tend to look at things a little more closely but even there I doubt that you would have trouble. If you are really concerned you could go to their web site and get in touch with them with your questions.
Generally, what's been done is to design for a narrow boat at the waterline and then flare out the sides (not as radical as concave) to get a good spread for the oars at the gunwale.
My oarlock pads extend out a few inches on either side and I have never been called on it.
Floatation is always a good idea so sponsons would be good for that reason but seem like a lot of work and maybe a lot of weight if you are not careful.

Hope this helps.
Jon

 

Thanks for that.

One issue I see is that most traditional models are designed first to carry a load and then secondly for speed. A 16' or 17' wl single with a design displacement of ~300 # is a different animal, more a canoe or kayak in hull form, but with the necessity of reasonable oarlock spread. Obviously that says outriggers, but that's coupled (by most rules) with a sliding seat.

Then there's the whole issue of what's fast around the course-varying conditions, from flat water to a seaway. Interesting problem.

Rob

 

I'm looking at buying a traditional rowboat planked hull for this season as it looks like I am going to be busy designing boats with the interest in current projects, including a Drake 19 that I have decided will be a new boat, new name but look like a twin to Drake just 19'. This means little time to finish the Bobby for this season. But it does mean getting some good design work done. In meantime, I need to find a boat to row or else I will go freaking crazy this year. Sailing is fun, but not the same as a great row. Currently, I'm considering looking at a doubled ender called the Sebago Skiff, a 17-footer that's think carvel planked and looks sweet. I'd compete in the workboat class presumably.

http://zachariahwhitridge.tumblr.com/

Towards bottom of the page....

 

Sound like a real nice reason for not being in front " oh well guys you know if it wasn't for all that beam!!!!!!!!

Any Foto's of version 3 ?

 

Here is a current picture...maybe...hope it attached!

Making slow progress. it should be ready for spring.
Sure is nice to have enough C clamps.

 

Jon , Thanks for the foto looking good you are nearly there, Im in Cape town, South Africa. well south in the southern hemis, 2 mths from now we'll be looking to winter,, and your boat will need to be finished for your summer,
good luck you should easily be ready
mike