I am considering building an Al displacement cruiser which would be trailerable. I'm quite happy to dawdle along at around 6-10 knots. I figure Al is the best option from a weight perspective. I would like something in the 22-24 feet X 8 feet beam range. I have found it incredibly difficult to find designs for displacement type boats in Al. There are plenty for planing hulls but most displacement designs are for ply/epoxy construction.
So my main question is....Can anyone point me in the right direction? Would prefer designs which including cutting files for hull. My plan would be to have the boat constructed by Al specialist and I would then fit it out.
Also wondering if there has been any interesting developments in displacement hull design providing greater efficiency and/or seaworthiness? As a sailor I'm quite keen on supplementary/steadying sail (but with no pretensions about a motorsailer as such). I'm thinking a 25-30 hp diesel would do the job as main propulsion source.
Looking forward to receiving some wisdom from forum members.
A 22 to 24 foot LOA monohull is not daudling at 10 knots. You could hardly find a less efficient speed for such a displacement boat. Even 6 kts is at the upper end for displacement speed when the LWL may be 1 or 2 feet less than your projected length and fuel economy will not be great at that speed. Some designs might make that possible, like a power catamaran but at 24' by 8' it will probably not be able to haul a lot of cruising accommodation around. Aluminum is fine for this use though. Heavier than wood but that is not an issue for a displacement boat.
I and a few others have been "doodling" a possible design for that use but none have been proven ready for prime time that I know of. I'm speaking of a high L/B canoe body keel and a planing main hull. I refer to it as a two phase design because most of the displacement is in the keel with the flat hull body having extremely light loading. Two phase because the keel is operating in displacement mode and the upper hull is planing at low speed of 9 or10 kts and above.
Aluminium boats are incredibly noisy with water lapping around the hull at anchor not ideal for a good night's rest imo. Like listening to marbles rolling around in a barrel. And then the insulation/condensation factor, which is not good. Assuming of course overnight use, which is probably on the cards, as a slow displacement boat will be restricted in range as a day boat.
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