DUO
425
the affordable parallel (biplane) rig cat
the fastest cat for your money
Record boat DUO 425 Ijmuiden.
The DUO 425 was the first parallel rig cat designed for amateur construction. The prototype was shown on the boat show in Duesseldorf 1984. We have the most experience with this sort of rigs. Many very fast and record breaking catamarans used and use this configuration.
I lost count how many DUO 425 are sailing worldwide, but it has to be more as 1000.
This is the easiest to build cat imaginable. Transport on the roof of a car is no problem. Set up time about 20 minutes.
The DUO 425 can be built in 120 hours. Many clients with absolutely no experience were proving it from doctors, over mechanics to bureau workers.
The hulls are wood/epoxy constructions. We use a sort of "matched hole technique" used in Aluminum aircraft constructions. You start with some precisely drilled holes, instead of Clegos we use screws. The asymmetrical hulls can be build flat on a table, or the floor.
Material
Each hull is made from only 16 main parts.
Here the list of materials
4 panels 4mm plywood
1 panel 8mm plywood
16m wood strips 20x20mm
5kg Epoxy as a base.
Plus of course two windsurf rigs
That is all. Check what you normal need for a boat with a length of 4,25m. Use the list to find out the costs for the boat.
The boat can handle a lot of wind. I sailed the boat till wind force 9 without any problem. And belief me, the boat is faaaast ! The picture at the right shows the "the sharked DUO". It was a second hand boat by the way. He reached at a channel near Ijmuiden 64 kmh (34 knots). Of course, the boat is easy to beach. No problem with my well known vertical rudder automatic.
I lost count how many DUO 425 are sailing worldwide, but it has to be more as 1000.
This is the easiest to build cat imaginable. Transport on the roof of a car is no problem. Set up time about 20 minutes.
The DUO 425 can be built in 120 hours. Many clients with absolutely no experience were proving it from doctors, over mechanics to bureau workers.
The hulls are wood/epoxy constructions. We use a sort of "matched hole technique" used in Aluminum aircraft constructions. You start with some precisely drilled holes, instead of Clegos we use screws. The asymmetrical hulls can be build flat on a table, or the floor.
Material
Each hull is made from only 16 main parts.
Here the list of materials
4 panels 4mm plywood
1 panel 8mm plywood
16m wood strips 20x20mm
5kg Epoxy as a base.
Plus of course two windsurf rigs
That is all. Check what you normal need for a boat with a length of 4,25m. Use the list to find out the costs for the boat.
The boat can handle a lot of wind. I sailed the boat till wind force 9 without any problem. And belief me, the boat is faaaast ! The picture at the right shows the "the sharked DUO". It was a second hand boat by the way. He reached at a channel near Ijmuiden 64 kmh (34 knots). Of course, the boat is easy to beach. No problem with my well known vertical rudder automatic.
Specification
Length : 4.25 m
Beam : 2.10 m
Weight hull: 17.00 kg
Weight all in: 44.00 kg
Sail area: up to 16m2
Length : 4.25 m
Beam : 2.10 m
Weight hull: 17.00 kg
Weight all in: 44.00 kg
Sail area: up to 16m2
Observe the low weight and compare with other catamarans with the same dimensions. Car transport is with this low weigth legally possible
Here the DUO 480C hull as example for the matched hole technique and The easy set up.
Parts ready to be mounted for a hull and a rudder
Plan with the right to build one unit
US $ 70,-
US $ 70,-
Copyright © 2025 by B. Kohler, K-designs
All rights reserved
That asymmetric hulls are easy to build is logical . 40% less time is needed. Push button to see how easy it is.
Biplane rig