designing a fast rowboat

That would be this design http://www.guideboat.ca/21ft_guideboat-photos.html

Unfortunately the plans aren't for sale as it was a custom order but it did have good results in the Blackburn http://www.guideboat.ca/21ft_guideboat.html

 

Last Chance

I've seen the "Last Chance" at several races and it is a fast boat. The reverse chine is unusual and effective in reducing waterline beam. Sean and Bill are edicated owers and their record shows it. I guess I'd prefer not to build their boat, just to stay unique At one point, Jon Aborn built a 20' double of his Monument River Wherry. I'd be interested in that also.

 

Inside Hull Color and Rear View Mirrors

What's the easiest color on the eyes? I presently use gray, but I know buff and green are traditional.

I've used an eyeglass mounted mirror which worked well but tired my eye muscles and made me fear going blind when the sun hit. I've tried various low gunwale and stern mounts which weren't that great. I've seen pictures of a high mount. Has anyone tried that?

 

Yes, it is.

Nope, that's a function of the midship section shape, not of the chine profile.

 

look again

On Last Chance, the reverse chine brings the waterline inboard effectivley reducing waterline beam. RE mirrors, I've tried several options including the eye glass mounted which gave me a headache and dizziness. the low mount wasn't too good either. Next option is to laminate a curved arm that will mount on the floor boards and bring the mirror up to eye level and close enough to be seen. Best option so far is my GPS with turn co-ordinates programmed in. just sit it on the floor boards and row in the direction of the arrow. It gets you there but you still need a miror to avoid collisions.

 

We've heard a lot of good things (speed foremost) about the guideboat design. One thing I'm curious about is the oar handle overlap on these various builds. I'm looking into my own design for an open water boat, and just found this excellent article on the Duckworks Magazine site, and it mentions a potential overlap problem. Could any owners respond about their own oar choices? Many thanks.

Design of Seagoing Rowing Boats:
http://www.duckworksmagazine.com/03/r/articles/rowing/index.htm

 

I'm actually looking for resources about ergonomics in rowing, and could use a little help. I’m a little taller than average (6’5”) and if I’m going to build an open-water capable boat I want to feel like it’s tailored to me and close to perfect. Who wouldn’t? But I’m not experienced with boat-building. I plan on a sliding seat (at an average height of between 8-11” above the heels), I have no oar preference other than high efficiency (but I don't mind some overlap on the oar handles), I’d like to be able to go out in moderate chop, and I can’t help but imagine that for any given rower their height and arm length would dictate an ideal width for the oarlocks. But I can’t find out how to calculate this (my wingspan matches my height exactly, so my arms are neither long nor short just normally proportionate).

I imagine that racers may have such a calculation for flat water boats, and that open water boats need higher freeboard, thus higher oarlock placement, and thus a better angle to compensate for chop, so the original calculation may work for me, especially if I also would like to use the boat when the water is calm. But I can also imagine that to keep costs down, the racing community has standardized equipment parameters, so nobody bothers with this sort of calculation. Which would make it hard to find perfect oarlock width for my build. Rats.

If I could calculate that ideal width, I'm thinking I can start designing the rest of my boat. But while I've read this whole thread with deep engagement and gratitude, I haven't come across this info. And it’s the first thing I need to calculate oar length, it seems. Any information on this would be most welcome.

To a lessor extent, I’d actually also like a formula for ideal placement of the oarlock: how far aft or forward on the boat seems pretty informal. I'd imagine that there is some ergonomic formula that I simply haven't yet found. Or it just may be like oarlock height - whatever feels right. I can live with that

(If I want max efficiency, I’m under the impression my ideal oars would be as long and light as possible, so probably a set of pricey carbon fibre with hatchet or an Alden Deltor blade types)

 

Ergonomics

Check out Oars for Pleasure Rowing by Robert Steever available (still, I hope) from Mystic Seaport. Great info. I made my red maple oars with the guidance from the book and am very happy with them.

 

spread

You have the horse before the cart. Beam dictates oar length. Your arm length dictates the distance aft of the thwart for the locks and your height dictates thwart height above the floor and height of the oarlocks. choose the hull you like and then place seat and oarlocks accordingly. Oar length depends a lot on strength. Inboard, you can overlap the handles a bit to help out the "gear ratio" a bit. The outboard length then is a matter of how hard or how fast you want to pull. There may be some nice neat equation for all of this, but I am unaware of it. Another thought: keep the thwart as low as possible to have maximum stability. Balance that against the height to be comfortable while rowing. I need about 5" or I get serious leg cramps. Some guys sit almost on the floor boards and are comfortable. Experiment a lot and don't lock in anything untill you feel it's right. On guide boats; I see two distinct styles: Paul Neil rows with short oars at a frenetic cadence and is ungodly fast, Mike Cushing pulls a longer oar at a much slower cadence. He is fast too. Good luck, let us know what you come up with.

 

-I'm fine with beam dictating oar length. But what dictates beam? There's got to be something, and I want to know that measurement before I choose a hull shape.
-I agree that strength is part of it. I would guess that strength isn't a linear relationship with height. There would be cube / squared thing going on where the torque would increase to a greater extent, probably necessitating greater spread. But I don't really know.
-With all the design information out there on the web, it's strange that if (hypothetically) a player in the NBA (average height 6'7', average weight 231 lbs) wanted me to make him a custom-tailored, high performance (but not racing) rowboat, I wouldn't know how to begin, and I'm having difficulty finding that information.
I think the strength factor is a hard-to-measure intangible, and racing selects for sprint endurance over raw strength, and has cost issues. So you don't get super tall (but slower stroke rate) racers, and you get standardized boat sizes, standardized oars, and adjustable riggers that can adjust (essentially) for variable shoulder width, but I suspect that every year there are taller guys trying out for crew that are limited to non-optimal equipment. Even with a coach who's good at optimizing it.

 

maybe not beam

Well, I found this, which makes sense to me. Maybe you do start with beam/span and oar length for boat design:

I've also found some racing rigging setups that allow up to a foot of span adjustment, I think per side. That would accommodate most basketball players, I'd imagine, so maybe multiple rower racing shells can handle really tall guys. Then, the knowledge of how to set span is just part of each individual rowing coaches' bag of tricks, and there's enough variation that no conventional wisdom or formula really exists. I'd still like to find this out though, so I'll keep looking.

 

what?

Just to clarify, for me, do you want to do collegiate stlye or openwater style? The parameters are not the same although similar. The high-tech stuff is more for skulls and the seat of the pants stuff is more openwater

 

Well, I'm actually all over the map on what I want. I keep going back and back to Dave Gentry's Ruth, but I'm worried it's a little too flat water (a sliding seat might make it too unstable), but WOW do I love its looks, so I'm actually thinking it would be such a great boat maybe I only take it out when things are calmer. (I'm also imagining a little battery pack and an internal micro LED lighting system under the gunwales - it would glow in the dark).

I want fore and aft buoyancy, and maybe covered decks, enough that I could put a water gate in the transom just above waterline and row out of any swamping, and the option for a passenger (ideally I could move the rowing station forward to balance boat when with passenger), so Keith Quarrier's Annie is definite contender, as is the Newfound Woodworks Rangely, which I find to be beautiful.

The Wayland Merry Sea also is in the running, though not as pretty as some of the others. But I love the price and ease to build, and I've been imagining a design compromise that's similar (maybe with the nose from Gary Baigent's gorgeous custom).

I'm reasonably sure I'll end up with a boat skinny enough that I'll need to build outriggers, but on the other hand there are some Wherry designs that are gorgeous and have stability and may not need them. As I said, I'm all over the map. I'd love to know my spread measurement so that I consider ideal beam, and then the needed length of the outriggers.

It's basically hard to accept the Piantedosi system at one fixed width. I'm guessing my ideal spread is wider, and will need to be custom. And I'm guessing the boat will slide through the water with enough ease compared to what I'm used to, I'll want longer than normal oars (I want carbon fiber).

Ruth:

http://www.boatdesign.net/forums/boat-design/designing-fast-rowboat-14250-45.html#post374106
http://gentrycustomboats.com/RUTH%20page.html



Annie:

http://home.comcast.net/~qboats/profile.html



Newfoundland Woodworks Rangeley:

http://www.newfound.com/rangeley17.htm



Wayland Merry Sea:


http://www.merrywherry.com/merryseatherugge.html

 

My question about ideal spread re rower's height has stumped "the authority site on rigging and rowing to help you get the most out of your rowing equipment."

I seem to need a biomechanical guy who's really into this stuff. Paging Dr Leo Lazauskas... (I'll send him an email)...

http://www.maxrigging.com/first-time-here/about-mike-davenport

 

Hate to sound like a broken record, but Steever's book. which is still available from Mystic for $15, has enough biomechanical stuff and formulae to keep you pondering for quite a while. I don't believe there are simple answers to your questions. Nor does Steever. He says each rower will have to figure it out for himself.