Any GP21 under way or finished ? GP21 vs PH22

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TomW1
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Re: Any GP21 under way or finished ? GP21 vs PH22

Post by TomW1 »

If you want a 20' boat then build the MG20 and scale the sides, transom and frames down to the height you want. I say transom because you will need to adjust it to the height of the new sides where they meet. Then increase it to the length of your motor shaft.

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Restored Mirror Dinghy, Bought OD18 built by CL, Westlawn School of Yacht Design courses. LT US Navy 1970-1978

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BarraMan
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Re: Any GP21 under way or finished ? GP21 vs PH22

Post by BarraMan »

I am back home and couldn't help myself - I had to go and have a bit of a play with this. More details and pics to follow, but for now I can tell you that if you built an MG20 hull, up-scaled by 10%, with the sides trimmed to 18" high and with a similar gunwale rub rail setup to mine........... you will end up with the max width of the boat at the transom being about 91" = 7' 7" ! 8O

Image

My boat is 98" at the max width across the top of the transom - right on the legal limit without having to get into Wide Load regs.

Just as a matter of interest, the sides of my boat are 32" high - but I added height for extra croc safety! :help:

I've set up a lazer level so that I can run the 18” line along the side of the hull - once the sun goes down a bit - then I'll try to figure out the length of the trimmed hull.

Image

I'm surprised that it doesn't lose much length - with 18" sides its still about 21'! :lol:
Last edited by BarraMan on Wed Apr 06, 2022 7:07 pm, edited 2 times in total.

Matkuz
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Re: Any GP21 under way or finished ? GP21 vs PH22

Post by Matkuz »

BarraMan, thank you very much, I really appreciate it. 7'7" its a lot of space, its very interesting what is the lengh of the boat after lowering sides.

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Re: Any GP21 under way or finished ? GP21 vs PH22

Post by Matkuz »

BarraMan, I think you convinced me :D with this lowered side panels its going do be a nice fast, smooth, fishing machine. Now there is a question, is there an option to build it with a foam core ?

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Re: Any GP21 under way or finished ? GP21 vs PH22

Post by TomW1 »

Matkuz I think you have made a wise decision. I am sure Jacques can provide the scantlings in foam, but do you really want to build in foam. Right now, to build a foam boat especially a high-performance boat like the MG will cost 3-4 times the price of the wood stich and glue MG. e-mail Jeff at the office if you are serious about building in foam to see if they already have the plans or if Jacques will need to draw up the scantlings. There are S&G boats over 20 years old and still going.

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BarraMan
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Re: Any GP21 under way or finished ? GP21 vs PH22

Post by BarraMan »

Matkuz wrote: Sat Apr 09, 2022 1:08 am BarraMan, I think you convinced me :D with this lowered side panels its going do be a nice fast, smooth, fishing machine. Now there is a question, is there an option to build it with a foam core ?


Ha! I didn't actually set out to convince you of anything. :doh: I just made a suggestion based on personnel experience and then answered you questions as best I could! :lol:

It would be an interesting build though! If I was 20 yrs younger I would think seriously of building MG20 based bass/barra boats commercially! :D

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Re: Any GP21 under way or finished ? GP21 vs PH22

Post by Matkuz »

BarraMan wrote: Sun Apr 10, 2022 5:11 am
Matkuz wrote: Sat Apr 09, 2022 1:08 am BarraMan, I think you convinced me :D with this lowered side panels its going do be a nice fast, smooth, fishing machine. Now there is a question, is there an option to build it with a foam core ?


Ha! I didn't actually set out to convince you of anything. :doh: I just made a suggestion based on personnel experience and then answered you questions as best I could! :lol:

It would be an interesting build though! If I was 20 yrs younger I would think seriously of building MG20 based bass/barra boats commercially! :D
Haha, you are reading in my mind. That's my humble wish, to build nice bass boats. Here in europe, there are not so many manufacturers which are building nice fiberglass fishing machines. Most of them are aluminium boats. 8)

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