Rowing catamaran

Hello,

I am looking for plans, and measurements to build pontoons for a 15 /16 rowing catamaran with moving riggers.
Thanks, Lloyd

 

What's a 15/16 rowing catamaran?

How many rowers?

What purpose will the cat serve?

Fixed seat, moving riggers?

 

Hello, Please have a look at this site and it should answer your questions: description of the ROCAT rowing catamaran http://www.rocat.org.uk/boat/description.htm

Regards, Lloyd

 

Contact ROCAT, they not only have plans, they make them!

 

Hello,

Well, I have been in contact and they do not have plans and are no longer making the.
Thanks, Lloyd

 

That Rocat really is an amazing design - one would think that it would not be possible to 're-invent the wheel' (or the sliding seat arrangement in this case) when it comes to rowing - but they have, very effectively.
And it makes a lot of sense - instead of having fixed oarlocks on outriggers with the seat (complete with the weight of the rower) sliding to and fro, creating a lot of momentum, the seat stays fixed, and the outriggers are on hinges, allowing them to swing fore and aft.

I saved a copy of the video that was posted on the site, showing how it all works, and I wanted to post it here - but it is too large (15 MB).
However I found the same video on Youtube - here is a link :


@Lloyd Le Blanc maybe you could use a pair of Hobie cat hulls (either the Wave or the Getaway) for your Rocat?
Find your Catamaran | Hobie https://www.hobie.com/sail/
It should not be too difficult to find a pair for not a lot of $$'s.
OK, the hull form for the Rocat is probably much more optimised for rowing than the Hobie hulls, but I think the Hobie cat hulls would still give a good turn of speed, and would be much cheaper in the long run.

And it should be possible to copy the sliding outrigger system (with a bit of trial and error along the way) from the videos on line and the basic info available?

 

Hello, I have rowed a sliding rigger boat and they are really great. The International Rowing Association has banned them in competition as they were faster than conventional riggers. I have looked at using Hobbie outriggers however they are too heavy. I have refurbished over 25 single rowing sculls and have built two. I will be building two "stitch and glue" outriggers and have been working on the design of the sliding rigger. Thanks, Lloyd

 

Interesting, probably a big advantage in having less movement of CG in relation to CB.

FWIW last year I had a client interested in building a human powered catamaran to challenge the current Guinness distance travelled in 24 hours in a human powered craft. He was well versed in pedal powered paddle race craft. I was hesitant to do the deal citing the fact that a catamaran has a built in 40 % penalty in wetted surface over a similar monohull. But in running the numbers in Michlet/Godzilla it turns out that a catamaran will be competitive with monohull or proa configuration as regards total drag (friction and wave) in the speed range required to be competitive in the 24 hour challenge.

 

You would also get a decent hull shape from the Expandacraft kit, and they have mounted Rantilla's Frontrower on one:


The Frontrower should (meaning I am not speaking from personal experience) give you the advantages of the sliding rigger, you can see where you are going, and you can row with feet alone or hands alone, in case of injury: Forward facing rowing for canoes, rowboats https://www.frontrower.com/

The amas of a Hobie Tandem Island or one of the Windrider trimarans also look quite suitable as hulls for a single rowing catamaran. However, spare parts tend to come with a large markup. Decades ago, someone added up the cost of all the spares from which you could assemble a Hobie 14, and it turned out to be about twice the price of the boat as a whole.

 

Lloyd,

If they made them, then they had plans.
Did you offer them money for a set of plans?
Have you looked for a used one?
Even damaged you could get the measurements you seek.
Failing all those options, this is not a difficult design to recreate, no?

 

Hello,I have been rowing for over 30 years and I retirement have refinished 25 single sculls and built two.I have no problem rowing backwards and in the last couple of years have used a Bluetooth camera with a tablet to see where I am going and it works quite well. I intend on building my own outriggers and working on the sliding rigger.Thanks

 

Read this article Foam and Fiberglass Ama Construction https://amaconstruction.blogspot.com/2021/02/foamand-fiberglass-ama-construction.html

Take templates from the front and back half of a rowing shell, about 2.5-3m each side. Shape the foam according to templates on the underwater side, sand a nice rounded form for the deck. Use Al or carbon tube crossbeams. For a final version you can build crossbeams with the same foam plug method.

 

Darn, I really wanted to see the guy catch a wave.
That should be exciting going backwards!

 

Ya, me too!

I'd be a lot more comfortable in those conditions with a centre boat pod (capsule) wrapped around me,
but that's added weight which is not helpful.

Lloyd, I can see why you want those pontoon designs but I feel confident you could recreate them.