Doubling up the frame members size. OK?

Designs for inboard or outboard power

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film842
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Doubling up the frame members size. OK?

Postby film842 » Sat Dec 29, 2012 3:45 pm

The plans for the Little Hunk call for 1"x 4" frames and with net sizes that will give me frames of only 3/4" thickness. I believe the plans, but I'm thinking seriously of using common 2"x4" stock from lumberyards which will give me a new net of 1 3/4".

Finding 4/4 fir lumber (a full one inch thick) has become a bit of a test even though I live in Oregon, so being able to find good stock from local lumberyards would be a real benefit. I built the Hunky Dory years ago with 2x4 stock and was happy with it.

More importantly, is my desire to have a stronger boat even at the expense of the added weight. I'm also planning on extending the Little Hunk from 18' overall length to 21' and possibly using 1/2" plywood on the sides instead of 3/8".

Anyone have a thought on this? All opinions gratefully accepted.

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rocker
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Re: Doubling up the frame members size. OK?

Postby rocker » Sat Dec 29, 2012 5:03 pm

I have 2 sets of materials list for my TNT.1 says 3/4 inch stock and the other says 1 inch.Come to find out that 1 is net and 1 is gross thickness.Glen-l says 3/4 is the right stuff.1x4s are 3/4x3 1/2. :)
Scott again.
rocker13165@yahoo.com

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Bill Edmundson
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Re: Doubling up the frame members size. OK?

Postby Bill Edmundson » Sat Dec 29, 2012 5:08 pm

Generally these boats are designed skin on frame. Then we build them unibody and then add a pastic skin. They are plenty strong :!:

Bill
Mini -Tug, KH Tahoe 19 & Bartender 24 - There can be no miracle recoveries without first screwing up.
Tahoe 19 Build

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Andy Garrett
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Re: Doubling up the frame members size. OK?

Postby Andy Garrett » Sun Dec 30, 2012 11:05 am

When you say "common 2x4 stock", are you talking about typical pine boards used in home construction? If so, you may wish to reconsider. To my mind, the thing that makes a good marine quality wood is its ability to hold fasteners and bond using epoxies. This would be especially critical on a boat such as the Little Hunk, which has no deck to add strength to the overall 'truss system' or 'space frame' of the hull.

If you are talking about 2" sections of hardwood, you may find them difficult to find. At least they are around here.

If you must have a beefy boat for peace of mind, consider laminating two 3/4" sections of the recomended framing lumber together on maybe every other frame. Laminated construction is always stronger by its nature. It would also correct for any inherent weaknesses in the members themselves, such as inclusions, etc. If you go this route, you might be able to use lumber that is not premium quartersawn, which can be hard to find in the average stack of Mahogany planks.

That's my two bits, for what it's worth.
Andy Garrett

Perhaps the slowest Zip build in Glen-L history...

film842
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Re: Doubling up the frame members size. OK?

Postby film842 » Sun Dec 30, 2012 4:18 pm

Andy Garrett wrote:When you say "common 2x4 stock", are you talking about typical pine boards used in home construction? If so, you may wish to reconsider. To my mind, the thing that makes a good marine quality wood is its ability to hold fasteners and bond using epoxies. This would be especially critical on a boat such as the Little Hunk, which has no deck to add strength to the overall 'truss system' or 'space frame' of the hull.

If you are talking about 2" sections of hardwood, you may find them difficult to find. At least they are around here.

If you must have a beefy boat for peace of mind, consider laminating two 3/4" sections of the recomended framing lumber together on maybe every other frame. Laminated construction is always stronger by its nature. It would also correct for any inherent weaknesses in the members themselves, such as inclusions, etc. If you go this route, you might be able to use lumber that is not premium quartersawn, which can be hard to find in the average stack of Mahogany planks.

That's my two bits, for what it's worth.


Out here, the common lumberyard 2x4's are Douglas Fir and when dry, it's an excellent wood to use. Of course lumberyard 2x4's for construction can have knots and so forth, so the trick is to cull the pile and take those that you can use.

The larger Glen-L dory (Hunky Dory) specifies 2x4 frame construction and the Little Hunk is only slightly smaller, so that's why I'm thinking the way I am.

On the the hand, I like your idea of laminating double frames every other one. If I can find a good source of 1x fir, I might try that. Thanks.

Seiner
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Re: Doubling up the frame members size. OK?

Postby Seiner » Wed Jan 16, 2013 11:19 am

I used 1 x 4 CVG (Clear vertical grain fir) for all my structural components on my 20' Little Hunk. With the gaps all filletted and e-glass on the exterior, my boat is plenty strong.
also my boat is at 2400 #'s with full fuel and motor. The additional weight is due to the cabin and hardtop. I wouldn't want it any heavier.

Seiner
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film842
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Re: Doubling up the frame members size. OK?

Postby film842 » Fri Jan 18, 2013 9:13 am

Seiner wrote:I used 1 x 4 CVG (Clear vertical grain fir) for all my structural components on my 20' Little Hunk. With the gaps all filletted and e-glass on the exterior, my boat is plenty strong.
also my boat is at 2400 #'s with full fuel and motor. The additional weight is due to the cabin and hardtop. I wouldn't want it any heavier.

Seiner


Thanks for the pic. It prompts a couple of questions: What wood did you use for your sheer cap and are your frame gussets MDO plywood? Thanks.

film842
Posts: 9
Joined: Wed Dec 26, 2012 3:14 pm
Location: Wilsonville Oregon

Re: Doubling up the frame members size. OK?

Postby film842 » Fri Jan 18, 2013 9:14 am

Seiner wrote:I used 1 x 4 CVG (Clear vertical grain fir) for all my structural components on my 20' Little Hunk. With the gaps all filletted and e-glass on the exterior, my boat is plenty strong.
also my boat is at 2400 #'s with full fuel and motor. The additional weight is due to the cabin and hardtop. I wouldn't want it any heavier.

Seiner


Thanks for the pic. It prompts a couple of questions: What wood did you use for your sheer cap and are your frame gussets MDO plywood? Thanks.

Seiner
Posts: 40
Joined: Thu Feb 26, 2009 10:05 am
Location: Mercer Island, WA

Re: Doubling up the frame members size. OK?

Postby Seiner » Mon Jan 21, 2013 11:13 am

I used okume plywood for all the plywood on the boat. sheer caps and gussets. I guess any exterior would probably work as long as you could get the same number of plys as okume.

My hardtop roof has a foam layer however to minimize weight.

Seiner


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