Decking a Pontoonboat

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cyberbadger
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Decking a Pontoonboat

Post by cyberbadger » Tue Apr 19, 2016 10:36 pm

Hi,

I'm coming to the point were I am ripping up the carpet and plywood deck(Rotted) on the Nyitra.

1) Is Treated plywood Ok for Aluminum Pontoon-boat decking? (It's should never be submerged, just splashes.)
2) Any recommendation on reinforcing the area for the boiler. I was planning on having angle iron reinforcing running through like an X or Asterisk * to the aluminum support members that connect the pontoons to the deck(plywood). Can I get buy with just framing that in wood without metal reinforcement?

The unknown quantities unfortunately are the Nyitras boiler weight and the costquard capacity plate(faded). The best estimate I have is 900-1200 American pounds dry weight. I don't have the ability(scale) to weigh it right now.

3) Anything I should watch for, suggestions? (I am considering adding a third pontoon)

-CB
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barts
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Re: Decking a Pontoonboat

Post by barts » Tue Apr 19, 2016 11:01 pm

How big are the pontoons (length, diameter)? Stability w/ VFT boiler?

Don't use treated plywood against aluminum; the metals in the plywood will interact poorly w/ aluminum.

http://www.donan.com/knowledge-base/art ... ood-decks/

- Bart
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cyberbadger
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Re: Decking a Pontoonboat

Post by cyberbadger » Wed Apr 20, 2016 4:04 am

barts wrote:How big are the pontoons (length, diameter)?
They are 24 foot 6 inches in lenght, 19 inches in diameter. They taper at the front to something like a point.
barts wrote:Stability w/ VFT boiler?
Not tried, not calculated. I'm going to put it on the deck, above the center of the point of gravity. I was going to float it on my friends pond where a tractor would be available for rescue, to test for buoyancy and balance.
barts wrote:Don't use treated plywood against aluminum; the metals in the plywood will interact poorly w/ aluminum.
Good to know. Hmm...

Image

-CB
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Re: Decking a Pontoonboat

Post by barts » Wed Apr 20, 2016 4:58 am

So, your hulls displace 96 cubic feet in total.

http://www.tc.gc.ca/publications/en/tp1 ... p1332e.pdf

suggests that the carrying capacity of a pontoon vessel is

given by (volume * density of water - weight of vessel)/2

So

(96 cubic feet * 62.4 lbs/cubic foot - weight of (vessel, engine,boiler)/2

So if all the stuff you add to the boat (tanks, engine, boiler, etc) weighs
2000 lbs, the capacity of the boat will be 2000 lbs...

there are also stability calcs in there....

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cyberbadger
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Re: Decking a Pontoonboat

Post by cyberbadger » Wed Apr 20, 2016 12:15 pm

barts wrote: So if all the stuff you add to the boat (tanks, engine, boiler, etc) weighs
2000 lbs, the capacity of the boat will be 2000 lbs...
That 3rd pontoon is starting to look mighty appealing. :lol:

Back to Decking, if I shouldn't use pressure treated, can I use any plywood other then marine plywood? (Like anything from Home Depot/Lowes)
I plan on painting it.

-CB
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Re: Decking a Pontoonboat

Post by fredrosse » Thu Apr 21, 2016 9:53 pm

You can use 3/4 fir exterior plywood, exterior rated. But it will check with just paint. You definately need to seal the edges with epoxy or vinyl resin. For real long life fiberglass cloth over plywood, with vinyl resin(cheaper, not as good) or epoxy resin (expensive)

I made a new transom for a fiberglass sailboat with 2 layers of 3/8 exterior fir (wanted to make a curved transom, hence two layers, & glue together while bent) , covered with 10oz fiberglass cloth and vinyl resin, holding up perfect after 5 years now.
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Re: Decking a Pontoonboat

Post by fredrosse » Thu Apr 21, 2016 10:05 pm

19 inch diameter = 1.97 square feet x 24 feet long = 47 cubic feet x 62 lb/ft3 = 2930 pounds bouyancy for one pontoon fully submerged, or two pontoons each half submerged.

Should not exceed pontoons half submerged, so 2930 pounds total weight. A rough guess at steam plant, 600 to 900 pounds. 4 people = 750 pounds with lunch and refreshments, So how much does the hull weigh?

Fron the looks of the waterline stains on the photo, it looks like the pontoons are nearly half submerged when floating in its current condition without the steam plant?
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Re: Decking a Pontoonboat

Post by cyberbadger » Fri Apr 22, 2016 12:14 am

24 ft 1985 FD2400 Riviera Cruiser ... 1260 lbs
http://www.nadaguides.com/Boats/1985/Riviera-Cruiser

Some of the couches didn't come with, and the 2 stroke (These hydrocarbon engines, can't even get power every stroke - it's uncivilized!) engine is obviously not staying.

Never floated it myself. The owner said he had had 10 adults onboard without much trouble.

-CB
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Re: Decking a Pontoonboat

Post by Bob Cleek » Tue Apr 26, 2016 7:27 pm

Have you considered welding up a framing structure and putting a "diamond plate" aluminum deck on top of that? Fast, efficient, and probably lighter than plywood without the rot and delamination issues. And... it will never need paint.
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cyberbadger
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Re: Decking a Pontoonboat

Post by cyberbadger » Tue Apr 26, 2016 10:12 pm

Bob Cleek wrote:Have you considered welding up a framing structure and putting a "diamond plate" aluminum deck on top of that? Fast, efficient, and probably lighter than plywood without the rot and delamination issues. And... it will never need paint.
It would be nice. A cursory search online shows that is way out of my budget. Lot of square feet, 160 sq ft. (Currently 5 8 ft x 4 ft plywood)

-CB
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