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Plywood Bottom

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richardculver
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Plywood Bottom

Post by richardculver » Wed Jan 22, 2014 9:45 pm

I'am refinishing a 1950 Chris Craft 17' Special Runabout. I will be apply 5 layers, 1/8 inch plywood. Any suggestions on type of plywood and where to order? Thanks Richard

boat_art
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Re: Plywood Bottom

Post by boat_art » Thu Jan 23, 2014 6:30 am

Why would you do that?
http://www.boatartgallery.com
1956 CC Connie 47'
1959 Caulkins bartender
1965 Cheoy Lee Frisco Flyer
1953 Chris Craft Holiday
1941 Chris Craft Deluxe
Plus 8-12 customer boats at any time
God don't count the days spent messing around in wood boats.

Jim Bell
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Re: Plywood Bottom

Post by Jim Bell » Thu Jan 23, 2014 7:26 am

boat_art wrote:Why would you do that?
X2? :?

jfrprops
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Re: Plywood Bottom

Post by jfrprops » Thu Jan 23, 2014 9:26 am

x3

john in va
1980 Fairchild Scout 30
19?? custom Argentine Runabout 16'
1954 Whirlwind deluxe dual ckpt 16'
1921 Old Town Charles River 17' (founding Captain, James River Batteau Festival)

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Doug P
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Re: Plywood Bottom

Post by Doug P » Thu Jan 23, 2014 10:50 am

ditto :roll:

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tkhersom
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Re: Plywood Bottom

Post by tkhersom » Fri Jan 24, 2014 8:03 pm

X4! :shock:
Troy in ANE - Former President CCABC

1957 CC 21' Continental "Yorktown" (Mom's boat)
https://www.chris-craft.org/boats/22625/
1985 Formula 242LS "Gottago"
1991 Formula 36PC "Band Aids"

Life Is Too Short To Own An Ugly Boat

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Doug P
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Re: Plywood Bottom

Post by Doug P » Fri Jan 24, 2014 8:55 pm

richardculver wrote:I'am refinishing a 1950 Chris Craft 17' Special Runabout. I will be apply 5 layers, 1/8 inch plywood. Any suggestions on type of plywood and where to order? Thanks Richard

Richard, I see you are new to the forum and perhaps we are not greeting you in an informative manner.
We are all wondering why you would need 5 layers of ply, was that the bottom that was there?
I would recommend you search "Boat Buzz" for better info on bottom replacement,
...meanwhile, Welcome Aboard :)
Doug

boat_art
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Re: Plywood Bottom

Post by boat_art » Fri Jan 24, 2014 9:00 pm

I agree with Doug. I might also suggest Dannenburg's book on restoration.
Tom
http://www.boatartgallery.com
1956 CC Connie 47'
1959 Caulkins bartender
1965 Cheoy Lee Frisco Flyer
1953 Chris Craft Holiday
1941 Chris Craft Deluxe
Plus 8-12 customer boats at any time
God don't count the days spent messing around in wood boats.

boat_art
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Re: Plywood Bottom

Post by boat_art » Fri Jan 24, 2014 9:03 pm

http://www.boatartgallery.com
1956 CC Connie 47'
1959 Caulkins bartender
1965 Cheoy Lee Frisco Flyer
1953 Chris Craft Holiday
1941 Chris Craft Deluxe
Plus 8-12 customer boats at any time
God don't count the days spent messing around in wood boats.

jfrprops
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Location: Powhatan Courthouse Virginia
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Re: Plywood Bottom

Post by jfrprops » Fri Jan 24, 2014 11:15 pm

never heard back anything...wondering if this post was genuine??

John in Va.
1980 Fairchild Scout 30
19?? custom Argentine Runabout 16'
1954 Whirlwind deluxe dual ckpt 16'
1921 Old Town Charles River 17' (founding Captain, James River Batteau Festival)

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mfine
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Re: Plywood Bottom

Post by mfine » Sat Jan 25, 2014 9:51 am

Hopefully he is off researching his options. Plywood is a possibility for a bottom material just not the 5 layers of 1/8 he was proposing.

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bjornbakken
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Re: Plywood Bottom

Post by bjornbakken » Sat Jan 25, 2014 1:47 pm

Just playing devil's advocate here, as I would put a planked bottom on myself. Using 5 layers of proper 1/8" BS-1088 Marine plywood should not be any different than 3 layers of 1/4", for a 'West-System" (aka cold molded) bottom? Other than more work maybe? 1/8" would be much easier to shape to the correct curves, especially up front.

A well written article on "West System" bottom here:
http://www.acbs-bslol.com/gadgets/bottomreplacement.htm

Bjorn B.
1940 17' Chris Craft Deluxe
1958 Riva Florida No. 319
1955 Riva Ariston

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Brian Robinson
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Re: Plywood Bottom

Post by Brian Robinson » Sat Jan 25, 2014 3:35 pm

If a true cold molded bottom is what they are after, three layers is more than sufficient. Most use 4mm BS1088 for that size boat, but I suppose 3mm would be fine.
-Brian
1923 Hackercraft 23' Dolphin #03
1938 Gar Wood 22' Streamliner #6256 Empress
1952 Chris~Craft 19' Racing Runabout #363 Thunderstruck
Robinson Restoration, LLC (760) 468-1009

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bjornbakken
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Re: Plywood Bottom

Post by bjornbakken » Sat Jan 25, 2014 4:24 pm

Here is a little report on my first attempt on a cold molded bottom. Using 3 layers of 3 mm BS1088 plywood on a 18' Riva. This boat originally had a 8 mm single piece molded plywood bottom.
http://www.rivaflorida319.blogspot.com

Bjorn B.
1940 17' Chris Craft Deluxe
1958 Riva Florida No. 319
1955 Riva Ariston

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Doug P
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Re: Plywood Bottom

Post by Doug P » Sat Jan 25, 2014 4:37 pm

3mm .....is that 3M with an echo?

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bjornbakken
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Re: Plywood Bottom

Post by bjornbakken » Sat Jan 25, 2014 4:50 pm

Doug P wrote:3mm .....is that 3M with an echo?

No, it's 3 more money :)
1940 17' Chris Craft Deluxe
1958 Riva Florida No. 319
1955 Riva Ariston

richardculver
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Re: Plywood Bottom

Post by richardculver » Sat Jan 25, 2014 7:59 pm

Thank you for your comments. I guess its obvious I'am not a purist. I'am a retired middle school principal looking for something to occupy some spare time. The idea of west/5200 bottom comes from Bottom Replacement by Dan Nelson. This winter I'am replacing the chines, frames and stem as Dan Nelson describes in his article. In his article he uses three layers of 6mm Okoume plywood. I was thinking that five layers, 1/8 inch would be as strong but much easier to bend. I have read most of Wooden Runabouts Restoration Guide by Don Danenberg and it has been very helpful. Thanks Again, Richard

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Doug P
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Re: Plywood Bottom

Post by Doug P » Sat Jan 25, 2014 8:15 pm

Richard....your boat, do what you feel that you can accomplish.

Each layer will need to be screwed, with 5 layers you will run out screw-able areas, plus the price of fasteners will be darn expensive. Spend the $ on clamps and less layers.


(Finally....telling a principal what to do...#56 on my bucket list.)

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bjornbakken
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Re: Plywood Bottom

Post by bjornbakken » Sun Jan 26, 2014 10:40 am

Richard, I personally think 5 layers is redundant and more work. Using 3 x 6 mm as described by Dan Nelson will be plenty strong, but I second Brian that 3 layers of 4 mm should be sufficient on a 17' boat.

If your not a purist, I think a properly done cold molded bottom is just as good as a planked bottom. I have done both an "enhanced" traditional 5200 planked bottom and a cold molded bottom, and as an amateur a cold molded bottom is probably a little easier and more forgiving.

No need to screw each layer. Staple down each layer with Monel rust proof staples, and remove screws (if used) between each layer, as described by Dan Nelson. I did use bronze screws into the frames, keel and chine after the final layer, Mr. Nelson recommend ring shank copper nails between the layers

Bjorn B.
1940 17' Chris Craft Deluxe
1958 Riva Florida No. 319
1955 Riva Ariston

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