Floorboards

[jimch...@googlemail.com]

Hi all,
On the assumption that my boat stays above the waves long enough,
my next job is to put in floors. I've landed myself the job of
removing a library full of oak shelving which should do the job
nicely, but I;m not too sure what the best way of joining them
together or sticking them down would be - I've laid permeable
bubblewrap style insulation under the floor (over the ribs/joists, off
the bottom of the hull) and I could do with advice as to what to do
next - as I see it my options include:
- nail/screw the planks to the joists through the insulation
- nail/screw/glue the planks to crossways bits of wood lying on top of
the insulation (the whole floor would not be attached to the joists,
but this is a predominantly inland waterways boat, so it shouldnt get
too shaken up)
- biscuit joint the floor together into one big slab
- get the planks tongued and grooved and clip them together

My woodworking skills have not had a chance to develop yet, so nothing
too technical would be good.

thanks in advance,

Jim Potter

[Bruce in Bangkok]

Any time you do anything to a steel boat your first thought should
always be RUST, and most steel boats rust from the inside out.
One of the more common problems with steel boats is wood to metal
joints holding water and the metal corroding and the wood rotting.

I question what good bubble wrap is going to do under the cabin sole
(floor). Is this heat insulation? Prevent condensation?

I'm not a steel boat builder so don't want to be too specific but what
I have seen is the cabin sole bonded and screwed down to the steel
beams, usually with Sikaflex or 3M 5200 and stainless screws.
Depending on the location flush hatches are used to allow access to as
much under deck space as is possible - you do want to be able to
inspect for rust and clean and paint if at all possible as well as the
usual stowage.

I think I would recommend a plywood sub-flooring covered by some sort
of finish lumber. your oak for example. If you just lay down oak
boards they will undoubtedly shrink leaving cracks for dust and dirt
to filter down into the bilges.

You might try contacting Roger Long over in rec.boats.cruising. He
designs metal research boats and may have some ideas about laying wood
decks on steel (although I believe he works mainly with aluminum).

Bruce-in-Bangkok
(correct Address is bpaige125atgmaildotcom)

[CS]

My pine floor is 22mm T&G attached to steel beams with Wurth Zebra
Pias screws. Pilot hole in board and self tap into 6mm steel with
ease - up to 10mm with care!! There is a foam/foil insulation layer
under the pine. Getting boards T&G would probably be expensive - I
would be tempted just to put in some biscuit joints at say 300mm
intervals.

http://www.luxe-motor-kei.co.uk/internal/page/image35.html
http://www.luxe-motor-kei.co.uk/internal/page/image37.html

[jimch...@googlemail.com]

Brilliant - thatnks for that. Its good to have some idea that this
should work.
Do you think it's necessary to screw the floor down, though? I don't
really want to have marks in the floor... when I was a land lubber I
put down clip together laminate flooring that was just laid over the
floor, and was designed to move as it expanded(/warped?!) Is this wise
with proper floorboards on a boat?

thanks

Jim

[CS]

On 25 Jul, 12:04, "jimchuf...@googlemail.com"

<jimchuf...@googlemail.com> wrote:
> On Jul 25, 10:47 am, CS <colinst...@hotmail.com> wrote:
>
> > My pine floor is 22mm T&G attached to steel beams with Wurth Zebra
> > Pias screws.  Pilot hole in board and self tap into 6mm steel with
> > ease - up to 10mm with care!!  There is a foam/foil insulation layer
> > under the pine. Getting boards T&G would probably be expensive - I
> > would be tempted just to put in some biscuit joints at say 300mm
> > intervals.
>

> >http://www.luxe-motor-kei.co.uk/internal/page/image35.htmlhttp://www....

>
> Brilliant - thatnks for that. Its good to have some idea that this
> should work.
> Do you think it's necessary to screw the floor down, though? I don't
> really want to have marks in the floor... when I was a land lubber I
> put down clip together laminate flooring that was just laid over the
> floor, and was designed to move as it expanded(/warped?!) Is this wise
> with proper floorboards on a boat?
>
> thanks
>
> Jim

I've got several hatches cut through my floor to give bilge access/
storage, water tanks, deep freeze, battery box etc etc, so I have mine
screwed down. If no hatches might be worth trying with no screws -
and add later if needed and perhaps a few discretely under cupboards
etc.

[Steve Lusardi]

Jim,
It appears you have ignored my advice, but I will try again. Your boat and
you could be in very serious danger. So, again I will state "SURVEY THE
BOTTOM" before investing a single dime. It is very easy and inexpensive to
replace rusted plate. This is considered routine maintenance on steel boats.
Do it first. Then insulate the hull with sprayed polyurethane foam to
prevent condensation and more rust above the cabin sole only. Then think
about the cabin sole. The floors are those athwartship beams that tie the
frames together at the bottom. The cabin sole support lattice should tie to
the floors and the longitudinals along the side of the boat. This lattice
needs to be parallel to the design water line. It is generally acceptable to
do this on more than one level, if you should so desire for headroom and
other clearance purposes. Then the cabin sole should be made out of 1/2"
marine ply screwed to the support lattice, but you MUST layout freely
lifting panels in the cabin sole insuring 100% access to every inch of hull
plate below the cabin sole. This is a safety requirement, so that any
flooding that occurs can be readily stemmed, so think fast access. These
lifting panels typically latch in place, use no fasteners. Now, on top of
the plywood cabin sole you can glue and blind screw any dress wood strakes
or panelling of your choice. This dress layer should also be about 1/2"
thick. Now if you wish isulation against cold soak for your feet in the
winter months, you should obtain 1/2" or better, hard polyurethane sheet and
glue appropriately fitted panels to the underside of the cabin sole. You
must never use any insulation below the cabin sole, never obscure access to
the hull plate. Never use sheet plastic or any material that will sweat in a
boat. Never allow warm moist air to touch cold steel plate.
Steve

<jimch...@googlemail.com> wrote in message
news:9379ff47-a120-40ca...@w1g2000prk.googlegroups.com...

[Mik]

Regarding just the floor boards (although I'd listen to Steve on the
metal stuff), it is easy to T&G yourself. Go buy a 3/4hp router and the
2 appropriate router bits. The whole mess will cost you less than $300
if you shop around. Oak is hard, so you will need to make several
passes to make a good job, but T&G is a pretty straight forward process.
If you try to remove too much wood in one pass, you will know it, as
your router will sound like it is dying, and you will be pushing too
hard to feed the wood through.

Some of it can even be done on a table saw (works great for the rough
cuts to remove the shoulders)