Crazy idea?

Boats up to 15' for oars, power or sail. Please include the boat type in your question.
oithona
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Crazy idea?

Post by oithona »

After poor experience using and towing an inflatable dinghy I was looking for plans to build a rigid tender for my 25' yacht. I wanted something similar in size and shape to the PK78, but this boat doesn’t seem ideal for towing behind my boat, or for mainly outboard use.

Requirements:
1. Stitch and glue construction - Economical and quick build.
2. Less than 8' - car-topping, ease of build & space
3. Hull weight around 60lbs - lifting on to car roof.
4. Minimum 4 foot beam for load carrying and stability.
5. Optimal towing characteristics up to 6kts.
6. Chiefly for use under outboard power.
7. Planing capability not required, but a welcome bonus.

Loved the look of the GV10, but it’s too big. Sooo…

Playing around with scale using photos and diagrams from the Bateau web site and elsewhere indicated that a 'shrunk' GV10 would be very similar to PK78 in dimensions, but with aft sections better suited to towing, and capable of higher speeds with a suitable outboard. I am no small boat designer, and the principles may well be rubbish, but as L. J. K. Setright said*, “..if it looks right it is right!”

Image

This boat could be cut from 2 8x4 sheets of 6mm marine ply and 1 8x4 sheet of 9mm ply. Finished weight should be around 65lb.

Proposed ‘Garvey710’ dimensions:
Length over all 7' 10"
Beam 4' 4"
Draught 6"
Freeboard 11.5”
Displacement 440lb

Any constructive comment/criticism gratefully received, even if it’s just to tell me that I am completely 'out to lunch' – I know, already! I may even be crazy enough to build it!


* L. J. K. Setright: The Designers: Great Automobiles and the Men Who Made Them (1976). Follet Publishing.

jacquesmm
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Re: Crazy idea?

Post by jacquesmm »

Why would your design tow better than a shrunk GV10?

Let's wait for Evan's opinion (GV10 designer and owner).

I designed the D5 for my own use: fit on deck, outboard and oars and towing.
Several times, I damaged it severely times while towing in bad weather. It never started as bad weather but once at sea, you can't get the dinghy back on board without damage. It ended up sinking while towing.
My opinion is that towing should be reserved for protected waters or very good weather only.

Now, you can't take a dinghy on deck on a 25 footer . . . I don't have a solution except risking the tow or going back to inflatables.
Jacques Mertens - Designer
http://boatbuildercentral.com

oithona
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Re: Crazy idea?

Post by oithona »

Thanks for quick reply, Jacques, but I think you misunderstood.
This 'design' IS a shrunk GV10 - I'm saying it would probably tow better than, for example, a PK78.

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Re: Crazy idea?

Post by jacquesmm »

OK then, I think that would work but let's wait for Evan's opinion.
He uses a GV10 as a dinghy since many years.
Jacques Mertens - Designer
http://boatbuildercentral.com

oithona
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Re: Crazy idea?

Post by oithona »

OK, I'm going to build this, starting in a couple of weeks.

I was hoping for some comment on feasability from Evan, but maybe he hasn't seen this, or thinks it's too silly to be worthy of comment. Maybe the 'Field of Dreams' principle will operate here.

I have a couple of questions for Evan and/or Jacques before I begin:
In producing this design, I started with a Garvey plan supplied freely with the Carlson 'Hulls' design software, but wasn't happy with the shape. I imported it into the more sophisticated DelftShip program and started modifying it proportionally based on pictures and diagrams of other Garveys I'd seen and liked - the Garvey 10 Flex of Morten Olesen, but chiefly from Evan's GV10 - even to the extent of estimating dimensions and ratios from photos and diagrams on this site.

So - question is how much is this a modified GV10, and do I owe you guys $45 for plans and, more importantly, license?
While I have the plans I need, it strikes me that the additional information on construction from the plans would be useful anyway, so next question is, if I buy a set, how soon would they be likely to reach me in the UK?

jacquesmm
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Re: Crazy idea?

Post by jacquesmm »

It looks like this became your design but as you say, the specifications and building tips shown on the real plans are worth the price.
We ship the same day.

Warning about the software you use: unless you have experience with the program, the plate development may not produce perfect results. You could waste expensive plywood because of that. Proceed with caution for example by testing with cardboard first.
Jacques Mertens - Designer
http://boatbuildercentral.com

oithona
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Re: Crazy idea?

Post by oithona »

Jacques
Agreed - I have just placed an order for the GV10 plans.
Thanks for the useful advice.

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Re: Crazy idea?

Post by jacquesmm »

Thank you for the order.
The value of the plans is also in the tech. support you will receive here even if you modify the hull shape.
Jacques Mertens - Designer
http://boatbuildercentral.com

oithona
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Re: Crazy idea?

Post by oithona »

OK, I'm going to start building this tomorrow. I plan to complete the build in a week of pretty full-time work. I'll try to post some progress notes on the builders' board.

Thanks for the advice.

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Re: Crazy idea?

Post by peter-curacao »

A 25' yacht???? :doh: could be me but wont you call that a boat? :doh: I read back and forth looking for me misunderstanding number,s but no I think I didn't? :doh:

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