Thanks for your comments. Please see my responses highlighted with
**J**

On Jan 30, 6:19 pm, " wrote:
Jay Chan wrote:
Please let me know what you think about my questions in the original
post. Thanks.

** Jay, I'll post a few comments here; probably more later.. It's
Midnight here in Africa..
A (Few?) basic questions:
- How big is the boat? Length/Beam?
- Outboard, right??
- Is the whole hull glass/plastic?
- Is the transom sound?
- I picture an open boat where you walk on the "Deck" which is low in
the boat. Right? I might call that a "floor". Do I have the right
picture?? Got a camera?? :-)
- How does the existing deck connect to the hull? Side/Bottom? Or an
inner wall section?
- Does the center console sit on glassed-wood stringers or braces on
the hull bottom, or was it suspended by the deck?
- Um, Fresh Water or Salt? Mostly...

**J**

It is 18-ft with 7-ft beam, and it is a very typical center console.

It has a 115hp outboard.

The whole hull is fiberglass with wood structural members. The bottom
of the hull is solid fiberglass. I don't know if the side of the hull
is solid or cored. The deck is cored.

The transom is sound. The rottened core of the deck is not directly
connected to the transom (they are separated by a solid fiberglass
area).

Your picture of the deck being lower than the gunwale is correct. OK,
I will use the term "floor" to describe the deck. I have a page of
the boat in my web site he
http://www.geocities.com/jaykchan/index.htm

The existing floor is seamlessly connected to the side of the
gunwhale, and the floor is supported by wood stringers. There are
still rooms under the floor that I am considering using the space for
storage. The gunwhale is hollow with spaces that I may mount fishing
rods, speakers and such. I guess this probably means that the floor
is not structural and is not holding the side of the hull together.

The floor is not anchored permenantly on the wood stringers. They are
separated. I mean the floor is simply resting on the wood stringers
but not fastened to the stringers. Seem like the floor is simply
being held in place by the connection to the side of the hull. I
guess this also means that the floor is not structural, and I should
be able to replace the floor without hurting the structure of the
boat.

The center console is resting directly on the wood stringers, and is
not connected to the floor. I am not quite sure how the center
console is being attached to the wood stringers though.

The boat is a salt water boat. But it is left on a trailer. I guess
this helps a bit.

----------------------- Original Post -----------------------

The core of the deck of my small center console is totally wet and
rotten. I am thinking of taking this opportunity to make the whole
deck removable.

..snip

I will use 3 layers of 1/4" marine
plywood to form the new deck, glass it, and place it over where the old
deck was, and allow its edge to butt against the gunwale, and then
screw the new deck to the frame.

** I've built and rebuilt frames and floors, using wood, plywood,
glass cloth and West Epoxy.
I'm sure you can do this, with some planning.. I think you need to
get the old deck pulled out before you make any decisions; you may
find surprises. Hopefully no squirrels, like I did :-)

**J**
I will definitely make the final decision after I have cut the old
floor out. I don't think there will be any squirrel in the boat
because I have several nice/warm compost piles in my backyard that I
think will be more appealing than the cold/hard fiberglass boat;
moreover, I have a chimney that the squirrels also may find very
appealing (one did).

Currently, the old deck is integrated with both the left and
right gunwale in one piece.

**?? Is the "Gunwale" an inner wall, separate from the hull side??
Hmmm..

**J**
The gunwale is hollow. The inner side of the gunwale connects to the
floor, and the outer side connecting to the side of the hull. I have
a feeling that the hull is made in one piece from one mold, and the
gunwale/floor combo is made in one piece from another mold. And then
they are attached together like this (please use fixed-spacing font
like Courier to view the line art):

Gunwale/floor combo:

/----\ /----\
| | | |
| |
| |
|----------------------------|

|
| Attached to
V
Hull:

| |
| |
\ /
\ /
\ /
\--------\ /--------/
\ /
\--------/

**?? How close is the "deck" level to the outer chine level?

**J**
I figure the floor is probably 4 to 5 inches above the chine level.

If this is the case, I will have to leave some of
the old deck in place to hold the boat together. I hope not, and I
have a feeling that it doesn't. But I don't have enough experience in
how a boat generally comes together. Therefore, I would like to hear
what other people may say.

**Hmmmm

How many layer of fiberglass that we should put on top and on the
bottom of the new deck? As mentioned above, the new deck is going to
be composed of three layers of 1/4" marine plywood.

** Why are you using 3 layers of plywood? If you do, how will they be
attached to each other?

**J**
I get that idea by reading the guy in www.continuouswave.com who
replaced his rotten deck with 3 layers of 1/4" plywood all glued
together using thickened epoxy. His idea of using 3 thin layers
instead of 2 thicker layers is to be able to stack the joint. I guess
if I can find one large piece of marine plywood, I will be able to use
one thick layer instead of 3 thin layers. But I have a feeling that I
may have a problem locating one large piece of marine plywood. The
mail order houses seem to only ship in small pieces. I guess this is
about time for me to look for a mail order house that can ship one
large piece of plywood.

If I am going to use core material, I will use 4-to-5 layers of fiberglass on top, and
1-to-2 layers on the bottom. Is this number of fiberglass also
applicable in using marine plywood as core?

** That seems like a lot of layers for a 3/4 inch thick 'deck'. You
should be using some bracing strips, maybe glassed in, for stiffness
of the deck... I think..

**J**
Your idea of using bracing strips is good. Actually the rear deck
area of the boat is totally under-braced and I should add additional
bracing in there anyway. Let me ask you a quesion: Let say we have
added additional bracing to make sure the bracing strips are not more
than 2-ft apart, and we use 3/4" marine plywood (in one piece or in 3
thin layers combined). How many layers of fiberglass would you
recommend?

I know that you will recommend using 2 layers of fiberglass if I use
1/2" marine plywood instead of 3/4" because you have mentioned this
below.

How do we deal with the edge of the plywood when we are laying
fiberglass? Should we wrap the fiberglass around the edge from the
top to the bottom? Or should we not wrap the edge and simply treat the
edge with thickened epoxy?

** I would round over the edges about a 1/4" radius and wrap the glass
top to bottom. Wet the end grain a couple of times with epoxy, let it
harden, and sand before any glass. You want zero voids in the end
grain or water will getcha again...

**J**
Thanks for the good tip. I will follow this when I get to that point.

Did anyone try this before? How did it go? Any tip?

** If this is the "floor" AKA "part you walk around on" in an open
center console boat, yes, I've used unglassed 5/8" Plywood and glassed
1/2" plywood, with a maximum unsupported span of about 2 feet.
Similar construction for the roof of my Cuddy Cabin boat, and it's
"Front Deck". 2 Layers of glass/epoxy. Good bracing. Very solid
feeling...

**J**
Great to know this! This means 1/2" or 5/8" plywood is a viable
alternative to 3/4" thick plywood. Good, less thick means lower
weight. And I will use 2 layers of fiberglass/epoxy -- may be 3 (just
to be in the safe side)...

Thanks in advance for any info.

** I think I would consider making the "deck" removeable for sure.
But I think I'd make it in two or more sections, not one piece. If the
joining lines are on a nice solid frame piece, it will be strong, with
lots of stainless screws..

**J**
I have the same feeling too. I will be making the floor in multiple
small sections instead of one giant piece. A small piece is easier to
handle than a giant piece anyway.

Aside: I did not make the floor inside my cabin removeable,
originally. I recently cut it out with a sabre saw, and made a new
removeable section, after I had some rot in the original just-painted
1/2" plywood. After 26 years...

Hope some others will add their opinions. I have a few unorthodox
materials opinions and rot-prevention opinions, but I won't cloud
things yet...

Jay Chan

Regards, Terry King ...On The Mediterranean in Carthage

**J**
Enjoy your stay in Mediterranean, and I look forward to hear your
advice -- orthodox or unorthodox.

Jay Chan