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Catamaran conversion

Posted: September 26th, 2010, 5:26 pm
by almceachran
I am considering converting my A-class catamaran to a rower. It is 18' long, 7'6" beam and weighs 120lbs. The oarlock would likely have to sit 14" above the waterline for the oars to clear the hulls. I would appreciate advice on issues with the increased angle of the oar, also advice on type of oar. I would likely use a drop in slider.

Re: Catamaran conversion

Posted: September 28th, 2010, 3:33 am
by jamesg
Maybe your best if not only bet would be to convert to a 2x / 2-, reducing the beam to the span (or a little more) of a training shell. Then you can use two decent pairs of real sculls (or sweep oars) at a reasonable speed, adjusting the gearing to what actually happens, but won't need rudders (maybe just one small one), keels or a cox that all increase drag.

My guess is the sails on a Class A generate about 10kW in a stiff breeze; so you can't expect to go fast with just your 200 (?) W.

Of course all the tough problems remain: space, getting the thing in and out of the water, sculling into a headwind, transport. Maybe you could leave a jury rig on her with at least a jib for sailing into heavy weather. Downwind she'll go anyway.

On the A Class US site, I saw boats advertised at 5-6k$; so you could do a lot worse than sell her and get a couple of K1s or a K2 or even a 1x trainer. At least in a K you see where you're going and they only need a patch of mud to float on.

Re: Catamaran conversion

Posted: October 7th, 2010, 8:54 pm
by almceachran
Thanks James,
I have located a spare set of crossbeams and will likely shorten these to give me a beam of around 160cm. I am reluctant to sell the boat and would probably switch back and forth. I am on the ocean so storage, transport is not an issue and the catamaran configuration will handle rough water. I would love a shell but typical conditions are pretty rough.
I don't think a rudder will be required, under sail the boat tacks on a dime. Also windage is relatively low, although not like a shell.
Regarding the power of a Class A I have never calculated it, but she will lift a hull in 7 knots of wind, from that point on it is hiking out and bending the mast to de-power the rig. At 20 knots it is just to much for one person to handle.

Re: Catamaran conversion

Posted: October 8th, 2010, 8:35 am
by pmacaula
Suggest you try sending a message to Steve Clark, who has an ID on Sailing Anarchy. He is an A Class (and C Class and ...) sailor/builder and sometimes sculler. If anyone could give good advice on such a conversion, it would be him.

You can find lots of posts by him in the Multihull Anarchy forum, notably the thread 'Fred is in SO much trouble'.

Cheers. Patrick.

Re: Catamaran conversion

Posted: October 9th, 2010, 2:09 pm
by Byron Drachman
You probably already have seen this, but just in case:

Re: Catamaran conversion

Posted: October 9th, 2010, 4:10 pm
by Bob S.
Byron Drachman wrote:You probably already have seen this, but just in case:
Thanks for sending that Byron. I had never heard of it before. Damn shame that it was unsuccessful financially. (I wonder if FISA helped to scuttle it - like they did the moveable rigger.)

Bob S.

Re: Catamaran conversion

Posted: October 15th, 2010, 7:03 am
by almceachran
Byron - Yes it was the Rocat that got me thinking.

Patrick, Thanks for the lead on Steve Clarke - I will check it out.

Re: Catamaran conversion

Posted: January 17th, 2017, 12:54 am
by afriedma
Here's a photo of another rowing catamaran, an Aqua Cat:

I should think that this photo would give you good ideas on width between hulls, mounting a sliding seat, and installing riggers/oarlocks. If you set it up so that there is a standard sculling distance (spread) between oarlock pins (typically 156-162cm, or about 5' 3"), you ought to be good. If you got a drop-in rigger setup, then you wouldn't even have to worry about how to mount the oarlocks to the hulls. An Alden Oarmaster or a Row-Wing might be the way to go. I just bought a used Oarmaster I from Adirondack Rowing :

A guy near me is selling his Tomcat Skimmer rowing catamaran, which uses a Row-Wing drop-in rigger:
The spread on that boat is much greater than the width between the hulls. Apparently the company,, is still in business

Re: Catamaran conversion

Posted: March 14th, 2018, 4:35 pm
by frankieboy
Re the Rowcat. This was an interesting concept, not the twin hulled piece of it but the oarlock arrangement, very innovative and I believe designed to maximise the time that the oar blade is perpendicular to the hull, in normal rowing the oar goes through an arc and is less efficient at the front and back of the stroke, with this arrangement the arc was less.