Replace floor or not?

[Fishery Pokery]

Hi everyone,
I have taken the floor out of my Sib (Avon S460). It has probably not been out for years.
I found some damage, and was wondering what you guys thought, should I replace it with a one piece ply floor, or will it be ok?
Also, should the triangular thrust board be thinner than the main boards? It is on mine.
I was going to sand and paint it all, but if it needs replacing I would rather do it sooner rather than later.
I have also been thinking of changing it anyway, before I noticed this damage.
Many thanks for all help,
Geoff

[walruz]

If it was mine I'd probably replace the whole lot but definitely the section in the first photo.

Ian

[Seabay]

I am interested in the replies to this,
My Avon S340 has some damage to the floor also and I was thinking .... Do I change or repair.

[Sonar]

Originally Posted by Geoff_Jubb

Hi everyone,
I have taken the floor out of my Sib (Avon S460). It has probably not been out for years.
I found some damage, and was wondering what you guys thought, should I replace it with a one piece ply floor, or will it be ok?
Also, should the triangular thrust board be thinner than the main boards? It is on mine.
I was going to sand and paint it all, but if it needs replacing I would rather do it sooner rather than later.
I have also been thinking of changing it anyway, before I noticed this damage.
Many thanks for all help,
Geoff

What are the boards made of ?

[thornbackflound]

Looks like marine ply?dam expensive stuff aswell,i have made flooring with ply ,sealed it stained and varnished it at a cheaper price.as said mate the first one could do with replacing ,i would say

[markg]

measure it and see if you can cut them from 8x4 sheets of ply, i did a single piece floor in ours but it was a bit bigger boat and i had to use a 10x5 sheet @ £75
you can get away with wbp if you seal it and look after it a bit, wbp is cheaper than marine ply

[m chappelow]

our local marine ply supplier stopped selling marine ply years ago as it was too expensive and they recon that now all Exterior plywood is now resin bonded as marine ply was only difference is a eastern hardwood face on the marine stuff , i have made floorboard out of exterier ply and then coated it with glass fibre resin ,,resin and hardener only .i also coat my transoms and oars with it too much easier for me than traditional varnish .any how i dont think inflatable boat makers use varnish but use resin instead .

[wiLlfish]

Originally Posted by Geoff_Jubb

should I replace it

arsk de scotty dawg. hee luks lyke hee noes wot heez doin.

'wot doo yew fink de condishun ov dis wud iz scotty dawg'

'ruff'

wilF

[C-NUMB]

That might pend on what is the condition of the boat otherwise? Sanding and painting old ones is in my opinion not worth time and money envolved. If boat is otherwise ok, would replace with marine ply, starting with the first section. I would just copy the existing pieces one by one. 2K epoxy primer will give a long lasting protection but 1k paint might be enough fo marine ply. In my own experience ply in bad condition is noth worth the effort to repair, would You anyway trust it if things get rough? But for easy use, maybe You can keep them as it is?

[m chappelow]

as we are on about ply just had some small samples of materiels that modern lifeboats are made from,grp,carbon fibre ,e glass ,ect loaned to me by the rnli for use in some talks that i am doing, and the replacement for plywood flooboards as now used in the latest d class inshore boats is something called HEXALITE with an aluminium honeycombe core , half the weight of plywood but stronger,pity you cant get a sheet of that.

[Fishery Pokery]

Having thought on it (and discussed with my good lady wife!) I have decided to go with the new one piece floor.
Has anyone got any experiance of the birch ply instead of marine ply?
Also, do I make the one piece to replace the rear three square pieces, plus the front triangular-ish piece?
Or do I make one piece to replace all four panels, including the triangular-ish piece?
Cheers,
Geoff

[m chappelow]

Originally Posted by Geoff_Jubb

Having thought on it (and discussed with my good lady wife!) I have decided to go with the new one piece floor.
Has anyone got any experiance of the birch ply instead of marine ply?
Also, do I make the one piece to replace the rear three square pieces, plus the front triangular-ish piece?
Or do I make one piece to replace all four panels, including the triangular-ish piece?
Cheers,
Geoff

usually Geoff the front/bow of the boat will have a dead rise ,so the triangular bit will be seperate unless your boat is level all along the deck ,normally the main boards flat and level and the bow comes up to a rise so that will have to have a hinge or some woodern lugs or batterns for it to flex of some sort ,,i think when people say one peice floor it means the main board and the triangular bit is seperate .you should want the 3 square rear pieces as one main board then the front trangular bit seperate .

[Fishery Pokery]

Originally Posted by m chappelow

usually Geoff the front/bow of the boat will have a dead rise ,so the triangular bit will be seperate unless your boat is level all along the deck ,normally the main boards flat and level and the bow comes up to a rise so that will have to have a hinge or some woodern lugs or batterns for it to flex of some sort ,,i think when people say one peice floor it means the main board and the triangular bit is seperate .you should want the 3 square rear pieces as one main board then the front trangular bit seperate .

Thanks Mart, I thought that might be the case.
Has anyone come across Phenolic board being used for this application?

[Poly]

Originally Posted by m chappelow

...the replacement for plywood flooboards as now used in the latest d class inshore boats is something called HEXALITE with an aluminium honeycombe core , half the weight of plywood but stronger,pity you cant get a sheet of that.

http://www.hexcel.com/NR/rdonlyres/9...306404PPA4.pdf ?

Originally Posted by Geoff_Jubb

Has anyone come across Phenolic board being used for this application?

is it not quite heavy?

[chris123]

Just my £0.02, but I would stick with marine ply.Although less common than it used to be and more expensive, it is still available and should be better quality.

The OEM floorboards have a combination of thin plywood for light weight, and mahogany edge sections and stringers to give stiffness and load spreading.

If you increase the thickness of the floorboards, you gain weight; if you reduce the thickness of the edge sections you reduce stiffness and also increase the point loading on the tube / floor seams.

I would be inclined to make one floorboard, but with the same overall dimensions, stiffeners etc as the original boards. I suspect size for size and weight for weight plywood is as good a material as any, without getting into exotics.

As Mart says, you should keep the front board separate so that it can flex.

There should be a fixed plank across the boat between the three back boards and the front board. Does your boat have this?

There are probably as many ways of finishing the boards as there are posters on Ribnet . For simplicity and cheapness, a tin of International yacht varnish (the proper stuff from a chandlers not the B&Q equivalent) probably wins. For maximum performance (and cost!), a couple of coats of epoxy resin (to fully seal the boards) followed by a couple of coats of two pack polyurethane varnish (to provide UV resistance) will give you the best results, but is probably overkill.

Cheers

Chris

[Fishery Pokery]

I have not seen phenolic board before but have also heard it is quite heavy, so will rule it out.

My floor is just board into stringers, with aluminium channels between the boards. It is 18mm, so think I will stick with that.

Mine does have the plank fixed across the front.
Are other peoples floors usually thicker than the front triangularish piece?

Just have to work out how to connect the front of the board to the triangular-ish piece. At the moment it is aluminium top and bottom, bolted through the ply.
To be honest, I am thinking of doing the same again. What do you guys think?

Thanks a lot for all your help so far!
Cheers,
Geoff

[chris123]

If you are happy with the weight of 18mm board you should be fine. The smaller Avons used to use 1/4" ply with approx 1" edgings - I guess yours may be different either because it is a bigger boat, or someone has changed the boards from the OEM ones previously.

I think the triangular front board would be thinner than 18mm - on my old Avon S250 it was 3/8" ply with an extra strip 3/8" x 2" across the back edge (the pivot edge) where it butted up against the fixed plank. Not sure if it needs to be thinner - I assume if it is the same thickness it might save you materials.

I'm a bit confused about the connection you describe between the main board and the front board - normally the arrangement is:

Transom -> aft board(s) -> fixed plank -> triangular board

On my S250, the aft boards butted up to the back edge of the plank, and the triangular board butted up to the front, with nothing to locate them.

Aluminium top and bottom to locate the boards onto the plank sounds fine, probably more important with a bigger boat.

Cheers

Chris

[Fishery Pokery]

On these photos, the second picture is the first removeable piece (the triangleish) and the third picture is the piece that connect to it (the first of the three square boards).
The first is of the boat just after I bought it, you can just see the floor setup.

[chris123]

Whereabouts is the fixed plank, or was there a 'not' missing from your previous post ?

Mine does have the plank fixed across the front.

There is a sketch of how my S250 floorboards used to fit together here:

http://rib.net/forum/showthread.php?...on+floorboards

Cheers

Chris

[Fishery Pokery]

Sorry Chris, I meant mine doesn't have the plank inbetween, it has it right at the bow.