Designing and Building a 1x rowing shell

Sincere apologies for the intro of homeric length, I just wanted to give as much info as I could before asking my questions,

Hello,
I am going into my third year of graduate school pursuing a PhD in mechanical engineering, my research is in bio-inspired design for propulsion of UUVs and my work consists of hydrodynamic analysis of fin based propulsion as well as the design and construction of experimental underwater drones.

I grew up in the 1000 islands region of NY in the summers spending all my time on or around power boats, row boats, sailboats, really anything that could float. I also loved exploring the antique wooden boat museum up in Clayton. When I entered high school I lost a bet and joined my school's crew time. One of the obsessions in this sport I found joy in early on was the design of shells. One of my first days into crew I asked about hull design and a coach quickly snapped at me that hull design doesn’t matter and gave me the age old adage ‘it's about the horses not the chariot.’ I of course being 14 and chalk full of stubbornness and hubris became further determined to learn as much as I could on shell design. This intrigue later turned obsession has always lingered while being in the sport.

Meanwhile, in a short time from beginning crew, I learned to scull a single and never looked back, for the past 10 years I have been racing a single somewhat competitively at the club level (top half - almost top quarter at the Head of the Charles, nothing special but not novice). After college, I continued to train to today where I solely race head races. At this point, I find the added skill challenge of steering and longer distance more fun than straight line sprinting. However, in the past ten years I never was able to shake the questions around shell design, this was furthered fueled by learning to scull and being asked “How would you better design a single?” by the individual coaching me at the time. This question constantly pops in my head during training, how would I design a shell differently, and has done so more and more to the point where for the past 2 years I have begun being determined to build my own shell to race. Understanding this would be a several year endeavor. Part of the reason I decided to pursue my PhD was to have access to a water channel, wind tunnel, CFD software, and learn hands on skills in fluid mechanics to aid in this endeavor. Thus far I have done the following as a basis for trying to learn as much as I can:

-Used several CFD softwares in hydrodynamic analysis (Simscale, XFoil, WaterLily,jl)
- 3 years of fluid mechanics and aerodynamic background research and work both theoretical and practical
-Background reading of hull design, everything from various academic papers to books like Uffa Fox’s “A Seaman sense in Powercraft,” “Ready All Row” about George Pocock, “A History of Rowing” by Peter Mallory (not the full some odd 2000 pages but close to a half of it), “Rowable Classics” (forgot the author), and just about every blog under the sun talking about shell building.
-Watched videos of both Carl Douglas and Empacher building shells on Youtube
-Self taught basics in both woodworking, 3D printing, and composite skills (currently I do a lot of hull making with carbon fiber and Kevlar sandwich structures for UUVs, wet layup, vacuum bags, compression molds etc).
-3 years extensive experience in rapid prototyping
-years and years of CAD design work
-Reached out and spoken with Ted Van Dusen for advice
-I’ve reached out to a few old wooden shell makers online.

My biggest weakness not being brought up in my academics as a shipwright or a naval architect is not knowing what I don’t know. I understand there is much much more I assume I am lacking, in how to balance a hull, key drafting terms for understanding the lines of a hull, etc. If anyone has a general direction or more book/video/papers/person to reach out to on designing and building a rowing shell, just general advice, I would be very grateful,

Thank you!
-Arsenale

 

Sorry mate, what was the question?
All the basic principles apply as to a long, narrow displacement hull.
I've raced in fours and eights.
You're not going to better the design.
What is the objective?

Oh, and welcome to the Forum.

 

Bluebell got it just about right. Long, narrow, light.

There are details to be fiddled with of course. Among the details are; minimize wetted surface, if you want the boat to be able to turn you might need some rocker and a rudder, weight is of critical importance for the boat and for the oarsman. The surface finish is also of critical importance if you are measuring in seconds of elapsed time....or boat lengths. Marchaj made a big deal of surface smoothness and absence of surface undulations in one of his books. If you transport your boat on a car or trailer it will get invisible dirt and scum on the surface......wash the boat with a detergent before you put it in, etc.

First impression is that you are an accomplished scholar and an experienced oarsman. So........The comments above are stuff you may be entirely familiar with. Let us proceed............There are others here who are smarter than me. My own credentials, if any, are based on long experience and a wee bit of education.

 

You may use the application I developed for canoe or peapod design, including subroutines for the stability and the speed prediction. In my opinion, the main design trade off is exactly stability (both initial and up to ~ 20° heel angle) versus performance, it is mostly the lower waterline beam you can deal with (for your rowing programme, the sea state you may face, your rowing ability), all other things equivalent.
Gene-Hull Canoe 3.0 - new version for Canoe, Peapod or Pointu projects https://www.boatdesign.net/threads/gene-hull-canoe-3-0-new-version-for-canoe-peapod-or-pointu-projects.66983/

 

Sorry my question got lost in there, I’m asking if anyone were to have any advice on where to continue from where I’m at with research and skills to learn, ship design principles to learn, books, software etc on where to go from where I am in pursuing to design and build a shell, thank you for your time!

 

I’ll be sure to start with this! I was pondering three different ideas for a shell design, I’ll have to start with one at least though hahah. One would be a rather longer thinner shell, more so than they are now, I’ve seen two like this and read of another, one I’ve seen the length is around 32’ or 33’ but the beam is 9” where as most shells are 26.5’-27’ long and 11” and some change wide. But essentially an idea to sacrifice stability for narrower hull and increased length, try to keep wetted surface area from increasing too much, and then find a solution for stability issue (I have a few ideas). But first step would be to model a current shell design, quantify what its stability metrics are (I’m not quite sure how one defines the differences of one hull to another in terms of stability, if there’s a non-dimensional number or ratios to do so) and compare to a custom design etc. Using software such as yours and others I think I need to CAD a known hull to have something to compare to. Anyway, thank you for your help!

 

Thank you! I appreciate the kind comments, I may have some more to do before I may be called “an accomplished scholar” by my advisor hahah, your point on surface finish I think is often over looked by club level guys and even some “elite” rowers as they’re called. My father would always point that out (his degree is different but he was essentially a surface chemist for a good part of his career) and would always be reminding me to wash and polish my hull. I know US rowing rules and certainly FISA rules dictate no “ribblets” to reduce skin friction and any “substance they may change the natural boundary with water” or something to that effect. I kinda laughed at that because I assume the epoxy laminated layers and or various paints and polishes put on shells are designed to do just that but no seems to care. I’ve even seen various coaches trying to use different “boat lubes” and such to speed up their shells. It seems no one would care so long as they didn’t win by too much, funny mindsets in rowing world.

 

I would recommend Michlet a shareware "computer workbench" well suited to analyzing and optimizing rowing shells.
FWIW I share some of your obsession but agree with your coach in one respect. I've designed a number of competitive primarily paddle craft over several decades. Not a single one has ever won a race. However they have been the tool that people have used to win races and sometimes set records. Most recently three teams, single outrigger, tandem outrigger and tandem peddle driven crafts won their divisions in the Missouri 340 race.
Best wishes

 

Totally agree, its never just the shell. I’ll check Michlet out as well. I’m guessing there’s tutorials online for how to use it/or a manual in the software for how to poke around in it? I’m not sure if any current software has the capability but modeling the force impulses experienced by the shell I imagine is a key part to understanding how a small light craft moves through the water. I know NELO designed a shell couple years back that supposed did better at preventing rocker in the water by using a flatter hull fore and aft of the rower, (but then watching that shell raced at Henley that year it seemed to rock quite a lot) seemed like a key idea to consider how the hull experiences forward thrust and weight movement, instead of just considering a constant forward motion. Thank you!

 

This is the key issue. For the intrinsic stability, I proposed to use the GM1° value computed with the canoe weight + the rower one when sit in his normal rowing position X, Y=0, Z and supposed a fixed weight. See pages 29 to 32 of the user guide. If the GM1° value is positive, you have a passive initial stability in proportion of GM1°. If this value is negative, that means the rower should constantly compensate with its body weight while rowing hard and here is at stake the rower ability. But in both cases, the GM1° value can be an objective criteria to compare two designs. You have no real merit to design a more performing boat if she has a lower GM1° than the reference one, it means that you just ask the rower more ability. The real challenge is to design a better boat at same GM1°.

 

Excellent, thank you! I'm sure I'll have more questions in the near future on this, I appreciate your time.