Cheap to run, cheap to build electro plywood cruiser ?

ASM
I will be able to fiddle with the existing hull to get those changes.

The width change needs to be considered. If you intend to trailer it then the limit is probably 2.5m without a permit. Not sure of your road rules. Is this an issue? If not then specify what width you would like.

Also the idea with the stabilisers is to have them just kissing the water. I will set them so at design displacement the KMT is at 0.8m. This should be above the centre of gravity so it will sit level. When lightly loaded it might have initial flop when in really calm water but I doubt this would be a bother.

Rick

 

Rick

I guess 3 m would be a max beam, it is not intended to be trailered. I do not know if the 2000 kg displacement can be held if the width becomes too much since it will take material too !

 

ASM
You should consider composite flat pack construction. I am confident it could be built within 2000kg using this method using glass composite. I expect prices would be comprabable with marine ply construction maybe even cheaper.

Some of the curves are a little severe but this can be managed with single sided initial layup and then glassing the other side once in position.

Rick W

 

Rick

I am not at all familiar with flatapck composite panels, I know a bit of woodworking and have a good address for fair priced okoume plywood. Imight do a combination of both, so flat side above WL in composite and the cabin top as well, so the heavy parts as low as possible.

 

Here is some stuff for the ASM9. It is a bit rough and would pay to make it from cardboard first to check the detail. I did not spend a lot of effort fairing.

The panels are scaled 40:1 and the stations are 20:1.

I am not in a position to check these. They are straight from Delftship.

Rick

 

Second set.

Rick W.

 

I should add that the floor in the aft section is full width. This is in keeping with the idea of flat pack construction. You cannot make frames that exactly follow the stations because the outriggers are formed from the side of the hull, the floor and the long thin piece I have called "outrigger"

Hope it makes sense. Send a photo if you mock it up in cardboard.

It needs a bulkhead to tie the front deck to the aft flooring. If you do this it will have good torsional rigidity. I have not done a cutout for this.

I have not recalculated the speed v power but it will not take much power to do 6 knots. The design displacement is around 2100kg. It will sit nice and steady with this displacement.

Rick W

 

Rick

Thanks again, this is excellent work. I have actually got about a dozen of file-boxes in 1 mm thick cardboard, so I might use that as skin and thin ply for frames. Will keep you updated !

Since I do know how to work with AutoCAD, would it be possible to send files in that format ? So I can scale and print to scale, so I just have to copy it 1:1 on the cardboard.

Sandor

 

Delftship is much easier to use than autocad. Just download it and do your own developments to suit your scaling. It will take me a while now to produce plot files for each sheet.

I have attached the devlopable fbm file and a 3D autocad of the same thing. I have not used autocad for development so have no idea if that is possible.

Rick

 

Rick

It's getting the same message, but thanks again for all your effort. I have now Delftship, and exported the linesplan in AutoCAD, which I can use now to put interior, etc etc, into the vessel. I can also print the individual 1m sections to pin down on wood, making cut outs, or, finding someone who can precut them by CNC !

The power requirements etc, is that a function in Delftship too ?

 

Delftship will not give very reliable performance data from what I have looked at. I use Michlet and find it to be very close for slender hulls.

Rick W

 

Couple of articles about electric power and an easily driven hull.
Page 56 in http://www.proboat-digital.com/proboat/20080607/
Sabdes 50-meter Axe-Bow. http://www.yachtforums.com/forums/f...re-concept-sabdes-50m-axe-bow-superyacht.html

Regards.

Perry

 

Rick, Looking at your great design it seems the displacement is almost all in the box keel and the sides simply give stability to the vessel at rest.

Could a bit of angle of attack on the bottom of the box keel give enough lift (like a water ski) to get the sides clear , removing their drag underway?

FF

 

Fred
The drag from the "outriggers" will be very low in calm conditions. In fact if the boat is unloaded it could flop from one side to the other if the trim is perfect and there are no waves. I doubt that this would be noticeable problem as it only flops a few inches.

At design displacement the KMT is similar to the Atkin style hull I did for you. Difference with the ASM type hull is that the stability increases significantly once it gets a bit of roll.

Rick W.

 

Just a quick note of caution. Depending on thickness, density and skin weight, composite frp/foam or balsa panels are approximately twice the price of marine ply - at least here in Oz. You can usually get them CNC cut for little extra cost though, whereas getting ply cut would be an additional expense. Your weight restrictions may or may not make that extra cost worth bearing. It's also worth considering the additonal skin reinforcement that's required - foam squashes much easier than ply....