CNC Plans not Included

Yeah, I agree on that, why tempt somebody.

This is the video I mentioned with a snippet of infusion at 1:10 - https://youtu.be/oLSdZNRXnvk

Not sure what those ribs are (BulkHead Landings?). If so why don't they extend further up.

 

It is more work, but not difficult to include a round or V'ed forefoot with a box mould, either pre or post infusion. However, my preferred solution is a rockeries hull, which is more pitch resistant, potentially faster and easier to build. Not as easy to tack (although John Hitch's Wired apparently had no trouble), but that is not a problem with a harryproa. If you did put a shaped bow on it, I would still recommend a flat floor further aft.

Jorge,

Pretty sure those are partial ring frames, not bulkhead landings.

 

Yeah probably so but I think that concept would work well. It might require a trim on one side to make look right but I think it's the easiest way because you have a little play.

I was playing with Graingers Flying Fish 50, assuming an open cockpit, I stretched the bow 5' and the stern 5' without touching anything else. That shouldn't add too much cost, looks awesome and probably increases the amount of stuff you can carry without losing performance.

Here is a look at them together

 

Been contemplating retractable elec. sail drives or just elec. outboards connected to a portabracket (24" movement). I inquired about shipmotiongroup retractable drives. They are nice but wow!!

I don't think that counts the Torqeedo's, which means just one retractable unit costs more than the entire torqeedo system - 2 motors with batteries and controls .. lol who would pay that??

 

That is wow, must be a typo on the zero because I want the whole boat or a large percentage for 350K euro..
Jeff

 

yeah, 35K might be doable, I can't see them getting too much business at 350K. Schionning posted this guide on Facebook, right up there with the material cost of a 15 meter cat

 

A cat with daggerboards can have as little as 2' of draft, I don't want to ruin that by hanging motors off the bottom.

Since I intend to use electric, I just had an idea, why not mount them on the sides of the hulls like this mini sub.

EDIT: Ok I just heard back from Torqeedo and they believe it would be okay as long as hull is reinforced in that area. I think I just found my solution!!

 

I think mounted on the side, you will have issues with the prop coming out of the water, unless mounted mid ship where you could get them deeper. My thinking was to mount them on a kick up box on the last transom step that also had the rudder attached.

BTW here is a thread to the catamaran plan I'm working on:
http://www.boatdesign.net/forums/boat-design/45-cruising-catamaran-project-56566.html

My current plan is to release it Creative Commons (meaning free). I will have all the CNC cut files for the panels as that is how I plan to build it.

I'm not very far on it and currently making lots of changes based on feedback I've received.

-Bryan

 

I saw your thread, I like the look but I know very little about what makes a good Catamaran, keep bridgedeck high, nice big tramp up front, weight to centers, etc etc... just what I read but it's a great project. I downloaded Rhino and have been fiddling with it but think it might be overkill just to edit cut files.

Yes on the motors being mounted amidships, boat has a draft of about 2' so plenty of water. The other option would be as you say, on the stern with maybe a portabracket to raise and lower but I'm a bit worried about theft in that case.

 

a little bigger motor and this might work https://www.youtube.com/watch?v=j7rHjE9X6To&feature=youtu.be

 

Rudder motor

Devlin's Nancys China has been using that idea for decades now, not sure if he is the original, it's a cool idea if you can except the small drag penalty.

http://store.devlinboat.com/nancyschinadc.aspx

 

Also, it seems the problem of having the prop aft and popping out of water in seas, would remain.

 

I guess that would depend on how far down the rudder you installed it ?

A big cat is going to have a much deeper high aspect rudder than the little mono.

It may even fit in the junction of a T foil rudder ?

 

Uh Oh I said the "F" word !

 

There might be one drawback - The idea of keeping the prop up above bottom of boat is so I can motor in the shallows. In these cases, the rudder would be up.