designing a fast rowboat

Nordvincrew races in a class that is restricted to fixed seats and gunwale mounted rowlocks so his dimensions will be different to your sliding seat and riggers.

 

congrats

Rallard, a very nice looking boat. it should move along quite well. You need to go to a site or thread that deals in sliding seat ergonomics to get further information. Keep in touch as to how your boat preforms. We do have a development class and a class for sliding seats in our races, and I hope that other areas do the same. In regards to handicapping, i'm not too crazy about the idea. It's a small pond around here and we all know who we are really racing against no matter what the class set up is. Our huge Jersey Skiff used to be classed as a livery boat but every one knew it was a work boat and that is how we figured our place in the race. Pretty near every one knows what their boat really is and competes as such.

 

Many thanks, I will gladly report after trials of this boat. In the mean time would anyone have suggestions where I could get good plans for a "basque chalupa" for 4 or 6 rowers?

 

Mike1 inquiry

Mike1, you were inquiring about availability of plans for the rowboat that I built and some information about the carbon construction. Somehow my answer to you through e-mail did not get through. I therefore decided to send it through a regular forum post as I think it also could be of interest to other participant.

"Bonjour Mike Henry,
Your e-mail was sent by Boat Design .net via an old e-mail address that I do not use anymore. I have updated the change.
Thank you for the information supplied, it will indeed be useful.

Unfortunately, I do not have any plans. I looked at a few rowboats on the net and did like the hull shape of the Annapolis wherry. However I wanted a boat that I could use in rougher waters with better performance. So the drawing of the main lines are fairly similar to that of the Annapolis wherry except that it is longer at 18'4", has a bit flatter rocker line on the rear half bottom section for a smooter venturi effect and avoidance of turbulance at higher speed, higher midboat topend side lines for added safety in rougher waters are reached simply by using a straight line except for the last front four feet which is curved up by four inches to the bow, This also greatly simplifies& facilitates construction of the male mold on a strongback.
Since I did not have any plans, and simply made a rough drawing of what I wanted and first built a 110 cm model to make certain that the boat would sit as desired in water; next I built a strongback and temporarily installed 8 rough cutted cross section forms approximately spaced; next I temporarily installed 10 nice and straight white spruce laths at approximately equal distance to cover the mold form and fixed only at the back and front end cross section. This gives a fair idea of the global boat form and from there, all you have to do is to make desired shape corrections by moving the other cross sections fore or aft and if necessary make corrections also to the cross section forms themselves. I could likely provide drawings of each section that I could make directly from the mold and measure the exact placement of each section. The problem is that I am preparing to head south for the winter and will be back only in April; the rowboat and mold are already stored away.
The carbon rig and the seat rig are almost complete and are ready for trial next spring. For the oars, I made 2 simple molds for hatchet blades and built the shafts out of 3 layers of white spruce 5/8" planks glued with epoxy resin and 2 laminations of 9 oz. unidrectional carbon.
The schedule of laminations for the boat is from inside out: 1x 2oz. e-glass cloth, 1x 9oz. unidirectional carbon at 0°, 1x 9oz. unidirectional carbon at 90°, 1x 5oz. biaxial carbon 0/90°, 1x 2oz. e-glass cloth.I
I fortunately have access to a local resin formulator, good friend of mine who made a very nice 2:1 special epoxy resin very clear, designed to resist softening & higher heat, UV, and totally free of amine blush. It was a breeze to work with that resin and be able to sand it the next day without any washing and without any sandpaper clogging.

I do indeed have a fair bit of experience working with carbon, kevlar or glass and resins of various types. I most often do sandwich construction under vacuum( you can get an idea in a tread that I started in 2008 under the multihull section "A carbon fiber wing mast for my cat"). For this light rowboat application going single skin made more sense as I could easily obtain the required stiffness and mechanical forces through a simple schedule of laminations using mostly unidirectional fibers and longitudinal side benches in the boat.
In my view, the enclosed side benches are a must in such a small boat. They provide great strenght for the hull, great flotation and, in case the boat tips over, a person can reenter the boat fairly easily since the main weight of the water is held in midboat, the boat will still float above water level with one person inside and can be emptied from inside out.
I join a few photos that may be of interest and I hope that this can be of assistance for your project."

 

still working

After the last race, we decided that we're not in good enough shape to pull our 8'9" oars. I'm finishing two sets of cedar oars that are 8'4-1/2" long. they are done in style similar to the oars shown in Pete Cullers book. The blades are straight, long and narrow. The design as well as langth chang should let us pull a lot faster. As far as I can see, you can only go as fast as the tip speed of your oars. With the long oars we just can't get the tip speed we need. Out time was a bit off what we normally row but the competition is getting a whole lot faster. The winning fixed seat double beat out a lot of sliders and 4's and 6's. Right up near the top of the field.

 

This thread was, originally, asking for advice on designing a boat. Seems like this has been sidetracked quite a bit. As in any race, the athlete is the most important element. Oars are certainly importand. But this is a boat design forum. I want to hear about the boat. Without going through the hundreds of posts, I'd like to know if you guys ever designed and built a new boat?
To reiterate my thoughts on the design. I think something like an oversized canoe would work best. I would look up John Winters articles on canoe design. I think they would be applicable to you guys. I'm thinking something about four feet wide with a narrower waterline and a legth of maybe 18-20 feet.

 

As with most Boat Forum threads, the posters strayed from the original subject early on, so if you read the first few pages you will collect most of the relevant input on design, but there isn't much - we don't seem to have many rowboat specialists among our designers. There is a great deal on modifications and their outcomes, and commentary on other, successful boats. Most of us are just cheerleaders for the NVC these days!

Speaking for myself, I have picked up a lot on the importance of things other than the boat design, so I have broadened my awareness through this thread. I am sure that if you scan through the originator's posts you will find several design iterations and the results.

The fastest boats for the available power are probably rowing shells and racing kayaks with canoes several places down on the list. Race boat design depends on the kind of race, with stability having more importance in exposed conditions, wave resistance the key to sprints and wetted area more significant on the long haul since hull speed cannot be maintained indefinitely with a small crew in open waters.

Race rules rule - of course - so in handicap races that give preference to - or ban the use of - such performance aids as sliding seats and outriggers, rules are going to have a big design impact. These aspects of design are IMHO brought out in this thread better than those design-oriented threads that deal with the computation of arcane design ratios, which tend to be more useful in sailboat design for which they are intended and do not necessarily translate to rowboats.

It's a long read, but if you are serious you will be willing to devote the time . . .

 

thanks

To the ancient kayaker: thank you for your reply to river runner. Mine would have been fairly profane and not fit for publication. I'm on my 6th boat with 2 others in the planning stages. All are self-designed. Clint Chase has built several of his own design, or has modified an existing design. Ancient Kayaker seems to be a self-designed boat factory. We ARE designing and building, mostly by the seat of the pants approach. The auxillary conversations add to our general knowledge of our sport. Yes, the thread has evolved, and I hope that it is a place to go for all traditional rowers. Racing is great, but just being on the water in a boat that is a joy to row is wonderful too. One of our highlights is the New Years Day row. It is just a bunch of friends doing a recreational row then getting together for a pot luck lunch in front of a huge pot bellied stove with a roaring fire. For the icing on the cake, the location is in an old boat shop that is over 100 years old and is still a functioning boat shop. Way too cool. I hope people will continue to read this thread and contribute in any way that fits in at all. Nord

 

River Runner, you're in the wrong thread, no offense.

This thread is a serious course of education on boat design. It gets sophisticated, and is work to get through. Using computer designs and software to simulate drag and handling characteristics are complex issues, and it's great that this thread has some serious pros regularly sharing their wisdom.

Not a lot of shortcuts in boat design, and not a lot of easy, simple answers. My prediction is that if you read through this whole thread, your preconceptions are an endangered species. Most of what you thought you knew will evaporate, and by the time you're through, you'll be thinking differently (and very, very specifically) about what you want in custom boat.

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*Edit* I was curious, and found this post of yours in different thread:

In short, your attitude is off track. We've learned a lot about design and performance, enough to get very specific about design and performance related to environment and conditions.

I see you as having two options: you can keep your current attitude and just look for an established design that appeals to you, or you can accept that varying conditions are part of the water world and you'll never be able to have a boat that does everything well.

This thread was started by an ocean racer, and that's been the main theme that's anchored it. River running is not something most of us associate with fast rowboats (unless perhaps there's new sport of rowing against the current, in which case you'll be right at home).

Essentially, Ferraris can (and frequently do) do well at one track but not another. In fact, race cars are specifically designed to be as adjustable as possible. Changing the gearing, aerodynamics, suspension for each track is an art, happens every race, and is so sophisticated now that in fact onboard computers change the car for specific corners, on the fly.

As rowboats don't have these abilities, compromise is required in design. But for a specific condition, you can indeed design for a 'best' boat. If it's a rowboat, this thread is a goldmine for how to do so.

 

This thread is long, but I bet I"ve read it thru twice, if you don"t learn anything you aren't capable of learning. I'm working on my second pulling boat built since coming across this thread, & you can bet I've tweaked it due to things talked about in here,

 

- you're welcome! I've calmed down over the years, but there was a time . . .

 

ummm - umm - I just love to see things stirred up - ! Its just invigorating !
I hope to start Building a boat this spring using many ideas from this thread. It will be a double, sliding seat, with capability for a small passenger. Strip plank construction to the water line, then Ship lap to the gunnel for looks. Due to the long and lean nature of of this type of hull there will only be a "couple" of strakes - 3 would be nice. As light as I can make it and as narrow as I dare.
Any ideas of a good place to post pictures as it goes? - Nick

 

SC: there's a wooden boat forum in the Construction section that would be ideal, but if you're using your own design a thread in this (design) forum would help develop the idea and get inputs. You can add to your existing thread if it's about the same boat. I hope you have been doing more than just think about this for nearly 3 years though . . .

 

I just got around to reading the rspsonse to my post. A lot of people that know absolutely nothing about the subject they are replying to often make insulting posts about people's ideas. Not just mine. For instance, based on my own experience rowing and paddling boats down rivers, plus articles I've read on how to row a drift boat, and a DVD I own on rowing a drift boat, I pointed out an obvious failing of the current designs and proposed my own design, which on building it does seem to be superior. People that have never even been on a river, and know nothing about rowing rafts or drift boats, felt obliged to try and tell me where I went wrong in my thinking, without even seeing my design. I objected to this and rightfully so. It was extrmely obvious that they didn't know what they were talking about.
Now, I'm just pointing out that a Banks dory is an extremely poor design for a race boat. You can't use a racing shell on open water, sea kayaks aren't allowed in the type of racing, and past successfull open ocean rowing racers looked a lot like canoes, not dories, not kayaks, but canoes. If they had open water rowing races in the oOypics, the boats would look like wide canoes.
I have made a point of not trying to make anyone feel stupid that asks a question on this forum, unlike many others. Some seem to think it is their duty to discourage amateur designers by making boat design seem so incredibly complicated that no one could possibly design anything. Bull.
I have no idea why nordvincrew took so much offense to my post. I was simply trying to get things back on the subject of boat design and discourage him from listening to the people that were pushing version of a Banks dory, which would doom them to last place in any race.

 

Here is my idea.

What I was hoping to get was photos of the boats nordvincrew was using and the boats that were beating him. That's all. Now, here is a draft of my idea. It is an open design, but a decked canoe, like the Alden shell might work, though my feeliing about boats like the Alden is that they look like they would be very wet in rough water. My design has a waterline length of about 18 feet and a width of about four feet. It looks more swede form than it is. The widest point, at waterline, is actually only about 54% back.