design by Bernd Kohler - The Netherlands

Here is the next catamaran from my drawing board. This time it is a small power cat. The boat has been on my web page as a standard design a bit longer as a year. I was waiting to introduce the boat because an client from Bellmore/WA was building the first one. As you can see from the pictures, he made a professional job of it. No wonder because he is a professional.

ECO power boat in a beautiful setting meeting old and new.

The boat is derived from our ECOnomy cruiser design. The under water shape is only changed towards the transom. The interior layout is the same.

Interior layout

Construction is plywood/glass/Epoxy composite, as always. The boat can sleep up to four when an cockpit tent is used. The boat was designed as an leisure travel boat with a good cruising speed. Economical to use was very high on my priority list and I mean really economical. We expect 12 knots from 2 x 5 hp engines when light loaded. More to this later.


L.o.a. 5.50m
Beam 2.50m
Draught hull 0.22m
Weight 275 kg
Weight max. CWL 620 kg
Outboard engines 2x 5 HP

Here some construction pictures of the boat.

Hulls under construction

Front view
Right side up
Side view, cabin and cockpit
Engines mounted

Ron made a beautiful interior too. In general, the boat is inside as designed and shown in the plans. With all his experience, he knew precisely what he wanted. I quote him here:

"Two Brompton folding bikes or one inflatable double kayak fit under the berth flat.  Porti-potti below folding seat in starboard hull. Galley unit slides to center for access to port hull storage aft of cabin bulkhead (pantry boxes). The trim and galley was from a lovely sheet of 6mm Bruynzeel ply - left over from building Wayfarer kits twenty years ago - just had to use it. Table folds. Ice chest in cockpit doubles as table. 25 liter water jug in port side aft cockpit hatch compartment. As we have enjoyed our prior Jarcat for ten years, we knew just what was needed to make the Ecocat a comfortable "cottage on the water".  Snaps are for window coverings. Solar vent fan in forward hatch. Black access port on forward bulkhead to anchor locker.“

Looking aft
Pantry and part of the table
Cabin looking forwards

Ron has made extended excursions this summer. I quote again from one of his letters.

“So there we are with the most detailed data I can offer. Again, I am totally pleased with the cruising livability ( and trailerability) of the Eco Cat. Just want to rethink the power. I do think a single outboard is the way I would like to go.  One gives up the ability to spin the boat in place and the backup of two motors. The water is flat and green between the hulls so water should not fountain up the motor leg (past the baffle fins) as with the Jarcat. Control complexity, weight and cost and will be reduced (if done originally).  Fuel economy at any given speed should be a lot better as the 5HP Honda's are old tech vs the 9.9/15 heads plus only one motor. NVH (noise/vibration/harshness) should make life pleasant. And available speed will be much better. I would like to cruise at up to ten knots and, perhaps, have a fifteen knot potential.“

This is also my intention. I will discard the two engines for a single outboard installation. In the near future a trim tab will be added.

ECO in a nice scenery

It is very satisfactory for me as designer to see that the boat behaves, and was coming out precisely, as intended.

The plans consists of 13 CAD drawings and a 13 page description.



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