Waller 1480 vs Dix 470 vs some other ideas / semi swath

Rumars said:
Other systems for you to consider are sheated strip plank using spruce or fir, cold molding with veneer, cored and solid fiberglass with vinylester/polyester.
I would take a hard look at sheated strip and cold molding. Wood is so cheap that you can afford the best quality, the price difference to ply will probably cover the increased epoxy consumption, and there will be absolutely no doubts about the quality.
Click to expand...

First of all thanks for sharing your valuable thoughts!

This morning was researching other materials as well, and that was kind of interesting: Closed Cell Spray Foam For Boats - Captions Trendy https://captionstrendyuscms.blogspot.com/2021/05/closed-cell-spray-foam-for-boats.html
Was wondering if forming ~1m long sections of thin Al (0.8-1mm) sheet sandwich and bonding it afterwards somehow would make sense/be possible. Materials is one thing but also have to keep in mind construction, necessary space, place, assembly. The easier, simpler and faster the better. And ofc I realize that has to be some compromise
 
waterbear said:
Also, if you are inclined, you can draw your catamaran in freeship, then export it to michlet to calculate the drag and estimate the performance. This way you can see how much the weight of the boat and the fineness of the hulls affect performance. This of course will not tell you anything about windage, which can be a big problem for a low powered boat.
Click to expand...

Linux user here :-) But will try freeship with wine or in some windows VM, the other one I didn't hear before, but thanks for pointing it. I will definitely check it!

Also thank you for the estimations, I realize that on solar powered boat energy budget is very thin. My first plan was to arrange sliding roof for 2 layers of solar panels, so I would get around 19kW in peak, but now more and more I think of adding wind turbines instead.

I think you've missed very important thing about Maytech motor. I'm not totally convinced I want exactly this one, but I pointed this one in particular because it is waterproof motor. So it simplifies a lot construction and efficiency is a whole different thing in this case.
 
Daniel Mazurkiewicz said:
Was wondering if forming ~1m long sections of thin Al (0.8-1mm) sheet sandwich and bonding it afterwards somehow would make sense/be possible.
Click to expand...
Forget it. You can actually buy such panels ready made, building a boat out of them is another thing.
You seem to be fixated on Al. I don't know why that is so, maybe you want to visit the arctic, or are already equipped to weld it, or some other reason. If you don't have the money for a full Al build you can always build the hulls in Al and the deck and cabin in something cheaper.

As I see it, you live in a country where there is plenty of cheap wood and machining it is not really expensive if you don't want to do it yourself. Epoxy and fiberglass can be imported at good prices since you are buying by the ton.
The only other real alternative is a solid glass hull with polyester, altough I am not really sure there will be much savings over a wood core hull.
 
Daniel, I did notice the motor is designed to be submerged. However, you are ignoring a critical point I mentioned earlier: you need a gear reduction with a motor like that to get good efficiency, so you cannot connect it directly to a propeller. Just like a bicycle or car, your boat will need a transmission. Also, something I missed: the Maytech rpm 5000-8000 rpm vs 1000 rpm for the motenergy, which means you will also need a much higher gear reduction for the maytech.

The optimal propeller will be enormous and look more like an airplane propeller than a boat prop. It will also spin relatively slowly. Forget what you think a boat propeller should look like. You can see what I'm talking about here, where the builder of this boat uses a higher gear reduction and larger propeller to get much higher efficiency:

PREVIEW: Going Fast with a Modest Engine, Peter Sewell’s Propeller on Vimeo

Richard woods has this to say about aluminum catamarans:

"40ft is about the minimum size for aluminium and even then it won't be a great performer compared to a wood or foam sandwich boat. And that will be if keeping it empty inside. Most people prefer a wood or lined interior, not a "tincan", if for no other reason to reduce condensation. So you end up building a boat within a boat, which adds to time and weight. The bigger you go the less the aluminium weight penalty matters. But of course costs and effort to build/sail/maintain also go up."

"What do you want to do with our boat once you have it sailing? For example, if oyu plan a lot of high latitude sailing then aluminium makes sense, unfortunately a catamaran doesn't if you go through a lot of pack ice."

Again, if you want to build a solar boat on a budget, choose a lightweight design and use Okoume. The hulls of Richard Woods' Rhea, for example can be built in rounded V form with 60 sheets of 9mm okoume, which would only cost $5700 here in the US. There is an Okoume plywood manufacturer in Greece, so you may be able to get it cheaper where you are. If this does not fit your budget then you should build smaller.

And last point, if you're going to use wind generators, why not just use sails instead? Your boat will be much faster and it will cost much less.....
 
Rumars said:
Forget it. You can actually buy such panels ready made, building a boat out of them is another thing.
You seem to be fixated on Al. I don't know why that is so, maybe you want to visit the arctic, or are already equipped to weld it, or some other reason. If you don't have the money for a full Al build you can always build the hulls in Al and the deck and cabin in something cheaper.
Click to expand...

When I said 1m sections I meant something like that:
(ofc at different scale :) ), so didn't mean to use ready flat panels but panels shaped already into entire section.

BUT ... I hear you guys @waterbear and @Rumars - as you see I'm definitely open for some uncommon and new approaches, but in this case wood or plywood it is! Your arguments are hard to beat.
 
You must log in or register to reply here.
Forum posts represent the experience, opinion, and view of individual users. Boat Design Net does not necessarily endorse nor share the view of each individual post.
When making any potentially dangerous or financial decision, always employ and consult appropriate professionals. Your circumstances or experience may be different.

    • Back
    Top