Reply
 
Thread Tools Search this Thread
 
Old 30 June 2009, 03:30   #1
Member
 
Country: Canada
Town: Ottawa
Make: Zodiac MKII FR
Length: 4m +
Engine: 25HP Mercury 2-Strok
Join Date: Mar 2009
Posts: 32
Thickness of marine-grade plywood

Hi,

I'm going to be building my two-piece floor (Futura Mk2) tomorrow. I have the choice of 3/4" (19mm) or 1/2" (12.5mm) marine-grade plywood. Can someone tell me which thickness I should choose. I would prefer to keep the weight down, but am willing to sacrifice if necessary.

Thanks,

Vince
__________________

__________________
Urbanbiketech.com
Not a RIB, but definitely my baby.
urbanbiketech is offline   Reply With Quote
Old 30 June 2009, 06:47   #2
Member
 
chewy's Avatar
 
Country: UK - England
Town: Up Norf
Make: Avon SR4,Tremlett 23
Length: 4m +
Engine: Yam 55, Volvo 200
Join Date: Apr 2007
Posts: 5,217
How thick was the original floor, was it wood or alloy?
__________________

__________________
chewy is offline   Reply With Quote
Old 30 June 2009, 12:47   #3
Member
 
Country: Canada
Town: Ottawa
Make: Zodiac MKII FR
Length: 4m +
Engine: 25HP Mercury 2-Strok
Join Date: Mar 2009
Posts: 32
Hi,

I don't know. My current floor is an H2P air deck.

Vince
__________________
Urbanbiketech.com
Not a RIB, but definitely my baby.
urbanbiketech is offline   Reply With Quote
Old 30 June 2009, 13:17   #4
Member
 
Country: Canada
Town: British Columbia
Make: Gemini
Length: 4m +
Engine: 40hp 2 str
Join Date: Oct 2003
Posts: 2,151
Half inch marine plywood might be OK, 5/8" should be plenty, 3/4" is very heavy duty. The highjackers will give additional longitudinal support compared to a conventional inflatable keel. My boat model uses 5/8" marine mahogany plywood as the standard thickness, but I opted for 3/4" marine for the extra strength and rigidity. For me the extra bit of weight was well worth it. My 3 main aft floorboards (~ 48" x 36" per board) weigh close to 50 lbs each.

Can you also get 5/8 marine plywood? Is your supplier able to tell you the weight/meter2 of these different thicknesses. From there, if you roughly calcuated the surface area of your floorboards, you can determine whether the incremental weight increases are acceptable to you.
__________________
prairie tuber is offline   Reply With Quote
Old 30 June 2009, 13:53   #5
Member
 
chewy's Avatar
 
Country: UK - England
Town: Up Norf
Make: Avon SR4,Tremlett 23
Length: 4m +
Engine: Yam 55, Volvo 200
Join Date: Apr 2007
Posts: 5,217
I'd go for the thicker stuff!
__________________
chewy is offline   Reply With Quote
Old 30 June 2009, 14:31   #6
Member
 
Country: Canada
Town: Ottawa
Make: Zodiac MKII FR
Length: 4m +
Engine: 25HP Mercury 2-Strok
Join Date: Mar 2009
Posts: 32
Keep in mind that I have only a 25hp motor. I would like to keep it light but not if it means using thinner than recommended. I don't want to overkill it for the sake of it, either.
__________________
Urbanbiketech.com
Not a RIB, but definitely my baby.
urbanbiketech is offline   Reply With Quote
Old 30 June 2009, 14:43   #7
Member
 
chewy's Avatar
 
Country: UK - England
Town: Up Norf
Make: Avon SR4,Tremlett 23
Length: 4m +
Engine: Yam 55, Volvo 200
Join Date: Apr 2007
Posts: 5,217
If weights an issue can't you get some fibreglass ones made?
__________________
chewy is offline   Reply With Quote
Old 30 June 2009, 14:59   #8
Member
 
Country: Canada
Town: Ottawa
Make: Zodiac MKII FR
Length: 4m +
Engine: 25HP Mercury 2-Strok
Join Date: Mar 2009
Posts: 32
Quote:
Originally Posted by chewy View Post
If weights an issue can't you get some fibreglass ones made?
That's a pretty sweet idea actually. I'll look into it. For the time being (and I mean for my fishing trip 2 days from now), I'd like to use wood.
__________________
Urbanbiketech.com
Not a RIB, but definitely my baby.
urbanbiketech is offline   Reply With Quote
Old 01 July 2009, 13:13   #9
Member
 
Country: Canada
Town: British Columbia
Make: Gemini
Length: 4m +
Engine: 40hp 2 str
Join Date: Oct 2003
Posts: 2,151
After having had both aluminum and marine mahogany plywood floorboards, I much prefer wood for the following reasons:

- Marine plywood is considerably less expensive.

- If using a suffficient thickness, marine plywood it is much more rigid.

- Marine plywood is very easy to modify and customize in terms of anchor points for your particular needs & deck layout.

- You can easily & quickly make additional/spare floorboards. This way, depending on what tasks you may using your boat for, you can install specific floorboards that are set up for that particular task. This is why a good sized SIB can be considerably more versatile than a RIB of similar size.
__________________
prairie tuber is offline   Reply With Quote
Old 02 July 2009, 14:05   #10
Member
 
Country: UK - England
Town: North East
Boat name: Sarah Louise
Make: Honwave T38IE
Length: 3m +
Engine: 15 Yamaha, 8 Mariner
Join Date: Jul 2008
Posts: 228
If you painted the floor, would you get away with exterior ply, as the floor is not submerged? And if so, what paint do you use on them?
__________________
Fishery Pokery is offline   Reply With Quote
Old 02 July 2009, 14:17   #11
Member
 
Country: Canada
Town: British Columbia
Make: Gemini
Length: 4m +
Engine: 40hp 2 str
Join Date: Oct 2003
Posts: 2,151
Quote:
Originally Posted by Geoff_Jubb View Post
If you painted the floor, would you get away with exterior ply, as the floor is not submerged? And if so, what paint do you use on them?
The paint will quickly rub off at the edges. I doubt you would get a full season out of floorboards made of conventional plywood. A given thickness of marine mahogany will also be much more rigid than conventional plywood.
__________________
prairie tuber is offline   Reply With Quote
Old 02 July 2009, 14:21   #12
Member
 
m chappelow's Avatar
 
Country: UK - England
Town: yorkshire
Boat name: little vicky
Make: avon ex RNLI
Length: 3m +
Engine: tohatsu
Join Date: Mar 2008
Posts: 2,310
Quote:
Originally Posted by Geoff_Jubb View Post
If you painted the floor, would you get away with exterior ply, as the floor is not submerged? And if so, what paint do you use on them?
i was told by a marine ply supplier a good while back that most exterior ply was now resin bonded same as marine ply ,as a mate of mine was after some to build a boat with and said if its painted it should be fine ,though as p/t just said its the hard wood stuff that will be best .suppose you could give it a coat of grp resin .
__________________
m chappelow is offline   Reply With Quote
Old 02 July 2009, 15:00   #13
Member
 
Country: UK - England
Town: Cumbria
Length: 4m +
Join Date: Jul 2005
Posts: 126
Quote:
Originally Posted by m chappelow View Post
i was told by a marine ply supplier a good while back that most exterior ply was now resin bonded same as marine ply ,as a mate of mine was after some to build a boat with and said if its painted it should be fine ,though as p/t just said its the hard wood stuff that will be best .suppose you could give it a coat of grp resin .
Ditto!

My SIB has two different decks, one the original multi-section deck as supplied, the second one home-made from Birch ply. I looked at marine ply (£60/sheet!) but the supplier pointed me towards Birch ply for several reasons: exterior rating, 13-ply compared to 6-ply, resin bonded, used locally for boat hulls and also used by local hauliers for decking flatbed lorries without any problems. Best of all it was £29/sheet for 18mm
__________________
Time IS money, just depends how you want to spend it..........
stan_deezy is offline   Reply With Quote
Old 02 July 2009, 15:43   #14
Member
 
Country: Canada
Town: British Columbia
Make: Gemini
Length: 4m +
Engine: 40hp 2 str
Join Date: Oct 2003
Posts: 2,151
Thanks Stan,

The 18 mm birch plywood sounds like a good reasonably priced alternative. Let us know how it holds up.
__________________
prairie tuber is offline   Reply With Quote
Old 02 July 2009, 16:41   #15
Member
 
Country: UK - England
Town: North East
Boat name: Sarah Louise
Make: Honwave T38IE
Length: 3m +
Engine: 15 Yamaha, 8 Mariner
Join Date: Jul 2008
Posts: 228
Quote:
Originally Posted by stan_deezy View Post
Ditto!

My SIB has two different decks, one the original multi-section deck as supplied, the second one home-made from Birch ply. I looked at marine ply (£60/sheet!) but the supplier pointed me towards Birch ply for several reasons: exterior rating, 13-ply compared to 6-ply, resin bonded, used locally for boat hulls and also used by local hauliers for decking flatbed lorries without any problems. Best of all it was £29/sheet for 18mm
Did you treat the ply Stan? Did you paint it?
Also, did you us a turnbuckle or did you make it but up to the thrust board?
Cheers,
Geoff
__________________
Fishery Pokery is offline   Reply With Quote
Old 02 July 2009, 17:29   #16
Member
 
Country: UK - England
Town: Cumbria
Length: 4m +
Join Date: Jul 2005
Posts: 126
Ah yes, missed out the bit about treating the timber! Used a primer coat and then two coats of undercoat followed by two coats of International paint. Stood up to wear extremely well indeed. No turnbuckles required, butts up to the transom and the small bow board very tightly to keep the fabric taught. If the fabric shows any signs of sagging I'd seriously consider turnbuckles though.
__________________
Time IS money, just depends how you want to spend it..........
stan_deezy is offline   Reply With Quote
Old 02 July 2009, 19:07   #17
Member
 
Country: UK - England
Town: North East
Boat name: Sarah Louise
Make: Honwave T38IE
Length: 3m +
Engine: 15 Yamaha, 8 Mariner
Join Date: Jul 2008
Posts: 228
My boat has 3 pieces that lock into aluminium side channels, then a triangular piece with a hole in for the keel valve, then a smaller triangle that is permanently fixed to the boat.
Do you use the single piece to replace the 3 bits that lock into side channel, or do you replace all 4 removable pieces?
Thanks,
Geoff
__________________

__________________
Fishery Pokery is offline   Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off




All times are GMT. The time now is 12:59.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2022, vBulletin Solutions, Inc.