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Old 04-04-2013, 07:23 PM
pullark pullark is offline
Join Date: Apr 2013
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Location: brisbane,Australia
Displacement trailer boat in Aluminium

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.
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Old 04-05-2013, 08:01 AM
tom28571 tom28571 is offline
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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.
Tom Lathrop
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Old 04-05-2013, 08:13 AM
rasorinc rasorinc is offline
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Hear is one from Glen-L.
While this is done in wood the scantlings can be changed to aluminum. It shows you what you can fit into a 24' x 8' plan. They have others also.
Wood Lasts Generations
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Old 04-05-2013, 08:20 AM
DCockey DCockey is offline
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The first Timbercoast 22 was built in aluminum.
David Cockey
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Old 04-05-2013, 08:49 AM
Mr Efficiency Mr Efficiency is offline
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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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Old 04-05-2013, 10:41 AM
michael pierzga michael pierzga is offline
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Location: spain
Alum boats are typically termed WORKBOATS.

do some alum workboat googling.

Plenty of stuff out there...skiffs, micro tugs, workboats



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Old 04-05-2013, 12:50 PM
messabout messabout is offline
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Michael, that cute little tug boat makes me smile. I think I want one of those.....But wood not aluminum..
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Old 04-05-2013, 06:11 PM
SVO SVO is offline
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Schau hier in Holland,die Spezialisten für Metallboote.

Grüße from germany

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Old 04-05-2013, 06:40 PM
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PAR PAR is offline
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The tug is a wooden build conversion, I think a Devlin design.
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Old 04-06-2013, 05:19 AM
tomas tomas is offline
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Location: California
Love the mini-Tug. It was built by Dearden Marine, British Columbia.

They've built more than one (with different propulsion units)

The "Candu E-Z" is a plywood design by Berkley Engineering and berkeleyminitugs is a forum member here.
Berkley Eastman was in the USCG.

Plans are still available for this and 3 other mini-Tugs along with Boathouses.

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Old 04-06-2013, 06:55 AM
TANSL TANSL is online now
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pullark, I think I could help you with your project. If it seems appropriate, contact me through my e.mail:
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