A pedal powered catamaran with sail assistance

This is my second build. My first pedal powered dinghy worked well but my desires changed. I now want to be able to harness the wind on lakes as well as the power of my legs. Most of my sailing is likely to be on the nearby canal where pedal power is sufficient to cover perhaps 10 miles. I'm used to working with metal and am confident that I can bring the whole thing together at a weight of around 50 kg. I'll update this thread during the build, which may take me another 6 weeks before launch. I'll be using a pedal activated oar system which I've seen used successfully by a couple of other builders. It may not be to everyone's taste but I'm confident that I can meet my own aims. Click below for the full story so far.
Building my new boat. https://mountainbiker.online/2023/03/10/building-my-new-boat/

 

I just read the story in your link.
Can you post any copies of sketches done so far showing your proposed arrangement, and how the hulls will be joined, and the sail plan?
You mention that the hulls will provide about 360 kg of buoyancy - at what draft will this be? And how deep are the hulls?

Re your pedal activated oar system, will it be similar to Ben Kilner's (as per the video below) or a totally different approach?

 

Pride and dignity prevent me from sharing my plans/sketches! (They're very rough). I'll show some photos once I've done more on the steel parts. Brief details of my dimensions are as follows.
Length 2.34 m. This is also the length at the waterline.
Beam 1.20 m.
The hulls are 0.3 m wide and 0.3 m deep, so square in cross section.
Draft will be 12 cm with me on board.
The central 1.6 m of each hull has parallel sides with a taper to the bow and stern of 37 cm.
The pedal system is similar to Ben Kilner's but with the pedal shafts directly mounted to the paddles. The paddles will have telescopic shafts which I've seen used in another design.
Steering will be by rudder. I'll build in mounts for lee boards.
The sail will be developed later. I'm thinking of a crab claw with the centre of effort exactly half way along the hull.

 

I assume the 360 kg derive from totally immersed hulls, floating at deck level. With 12 cm draft it displaces around 140 kg.

Copies/images of the arrangement would be nice! I am courious what it is supposed to look like.

 

Yes 12 cm draft will account for a 50 kg mass plus my own 85 kg. 360 litres is the hull volume so completely submerged they will displace 360 kg of water.

 

Too bad you couldn't fair the lines on the hulls. Those sharp bends will create turbulence, but I don't know what kind of performance you're hoping to get, so it may not matter.

 

I've managed to do a bit more work on the frames which will link the 4 hull sections together. Here is one resting on 2 hull sections and leaving the beam at 120 cm with a length of 117 cm, so the total length will be 234 cm. One frame will be boarded with ply for a recumbent seating area. The other will contain the pedal drive system and mast step.

 

It isn't a great photo but this is my half built pedal mechanism. The pedals so far are 12 mm rods which are each attached to the lower sections of 2 telescopic arms via bushes. The paddles will then be attached to the bottom of these to push the boat along. I've made it adjustable so a stroke length can be chosen.

 

Will this paddle drive be similar to the Ophira,

Pedal Powered Boats https://www.boatdesign.net/threads/pedal-powered-boats.23345/page-147#post-931263

#2196

I'm very curious to see how well it works!

 

Yes. The mechanism works in the same way. I've made mine taller to keep the paddles more upright, entering the water around 30 degrees from vertical. There will inevitably be inefficiencies but leg power should overcome them to give me maximum hull speed capabilities. The aim is to cruise at 75% hull speed with a typical cyclists input of 150-200 watts.

 

For what duration, may I ask?

 

150 watts is easy enough for one hour.

 

I'm progressing with my build and hope to be ready to test by the end of this Month (April).
Boat building progress. https://mountainbiker.online/2023/04/11/boat-building-progress/

 

I've laid the components out and it might even have started to look like a boat! I only need to do some painting, a few small bits and accurately assemble. Then the exciting part, my first test on the water.

Trial build of my new boat. https://mountainbiker.online/2023/04/18/trial-build-of-my-new-boat/

 

Tomorrow may be the day for a first launch of my new boat. Exciting! Also worrying. All sorts could go wrong.
Close to launching my new boat. https://wp.me/pat7O8-1DH