When it rains, it...

[maxumized]

Pours. Or rots your flooring.

While I've been working through motor issues this off-season, I have a point where I'm waiting on some parts and decided to repair the "soft spot" in my floor. After pulling up the carpet, this is what I found.

What's sad is that this is a 1997... should be in much better shape, but the previous owner let it sit in the open rain / under a tree. It almost looks like the drain in the ski locker was plugged and let the mid to front section of the floor stay wet and rot out.

Looks like I've got more work on my hands than I thought. So, glassing isn't totally new to me as I built speaker boxes for a brief period, but the construction of this boat is new to me. I wish I had a diagram or blueprint of the original construction to see where the stringers and other supporting pieces are. I can see its a floor of 5/8" plywood with a layer of glass over it. Also a lot of foam filler.

If I knew how the supports ran, I would go ahead and start cutting out the deck, but I'm worried I'll cut something I shouldn't.

I've been reading several threads and have gotten a lot of good information.

Any words of warning and/or encouragement?

 

[a70eliminator]

Re: When it rains, it...

why not just get a circular saw and set the blade to only cut the 5/8 depth. Looks to be rotted enough that you could just start digging away till you get to a stringer then take some measurements and mirror the other side, start sawing!

 

[Mark42]

Re: When it rains, it...

Two words come to mind... Pressure Treated. Something to think about when choosing the materials to rebuild the stringers and floor.

BTW, how well sealed in resin/glass were the stringers and floor?

 

[5150abf]

Re: When it rains, it...

Makes me glad I have a tinny, can't stand the smell of fiberglass.

Goos luck, hopefully the damage doesn't go too far.

 

[maxumized]

Re: When it rains, it...

Circular saw idea sounds good. Think I'll give that a shot.

The plyboard only had a thin layer of glass on top. In the areas of the worst rot, there was standing water on top of the foam after pulling up the wood. Once I'm done, I'm buying a sunbrella cover. This all could have been avoided as far as I'm concerned.

The stringers I can see still look solid, but I may take a core sample to see. Also - pressure treated... that brings up a good question. If I'm going to glass over the plywood, will pressure treatment interfere with absorption of the glass resin?

The stern area looks to be pretty good, and the transom, too. However, I think I may go ahead and pull the entire floor while I'm at it. I'm sure it sat up for quite a while this way.

 

[Mark42]

Re: When it rains, it...

....The stringers I can see still look solid, but I may take a core sample to see. Also - pressure treated... that brings up a good question. If I'm going to glass over the plywood, will pressure treatment interfere with absorption of the glass resin?

According to AMA testing (the Engineered Wood Association), there is little or no difference in the strength of resin adhearing on regular plywood vs pressure treated plywood, even at a 65% moisture reading in the wood. In all their tests, it was the wood that failed, not the resin bond to wood. Read about it here: http://glen-l.com/wood-plywood/fiberglass-plywood.html

Some people have a real aversion to using p/t lumber in their boat. But as you can plainly see, regular wood tends to rot, even when sealed with a layer of resin and glass.

 

[jcsercsa]

Re: When it rains, it...

the only problem with the pressure treated is you cant let it touch aluminum , it coroads alum, john

 

[slasmith1]

Re: When it rains, it...

two words "marine grade".
two more "no carpet".

 

[salty87]

Re: When it rains, it...

drainage is what prevents rot

 

[Bob_VT]

Re: When it rains, it...

First words..... it can be done and when you are finished it will be better than when it was new.

Circular saw with the blade set to only cut the deck and start tearing. You should probably invest in a small shop vac to suck out the garbage as you go along.

From what I see you actually caught it before real damage to the hull was done. You will probably have to seperate the cap and hull...... you will need a place to work....... just take your time and do it right.

 

[a70eliminator]

Re: When it rains, it...

I like looking at the pictures, please keep them comming as you progress. I did mine in plain old 3/4 exterior grade plywood, figured it will outlast the rest of the boat, I applied a layer of fiberglass cloth to the topside only, mine was just a small 2'x 4' patch in comparison to what you have.

 

[92excel]

Re: When it rains, it...

below is a recent conversation about pressure treated or marine grade ply:
http://forums.iboats.com/showthread.php?t=287648

i would agree that you should do the entire floor while you are at it, no reason to do this section now and the other next year..

good luck and keep us up to date!

 

[maxumized]

Re: When it rains, it...

First off, thanks everyone for the replies!

After reviewing the comments here, along with the links regarding treated plywood / resin adhesion, I think I'm going to get started with removing the decking with the circular saw and will replace with pressure treated (marine grade if I can find it locally) plywood and a single layer of glass.

Question - if after removing the decking the foam appears to be waterlogged / damaged, is the typical action to remove completely, and replace? Is the purpose of the foam for additional structural integrity without much weight or loss of buoyancy?

Will be taking pictures as I go... hopefully to chronicle the success story! If the project goes up in smoke, I'll just delete all evidence. :redface:

 

[drewmitch44]

Re: When it rains, it...

You better have a few months to get the pressure treated dried. 65 is dry for pressure treated. On average when you buy it at a lumber or Blows or Home Cheapo it is at about 96 humidity. If you heat it too fast it will warp and cause voids in the plys of wood. Thats pretty much the bottom line. Also if you heat it even slow it weakens the bond in between the plys of the "plywood". I would not use ply in a boat if you are going to use fiberglass on it. Just my opinion.

 

[Mark42]

Re: When it rains, it...

I agree with drewmitch44 about avoiding the home centers for quality lumber. Go to the local lumber yard and ask what grades of ply they have in p/t. I order my lumber from the local yard, and it is never as high a moisture content as the home center stuff.

Regarding the use of foam, if you are willing to accept the consequence of not having floatation if your boat takes on water, then leave it out. Another feature of having foam is it deadens sound, so you may hear the water on the hull better if there is no foam. And depending on how well a foam job was done, it could add some rigidity to the hull.

BTW, recreation boat builders are NOT required to use marine grade lumber in the boat. Some do, most do not. The AMA suggests that p/t lumber be used in boats. Especially in "extreme marine environments". I tend to agree.

Just something to think about.

Lets see more pics!

 

[JaSla74]

Re: When it rains, it...

You're definitely better off ripping up the whole floor. What may seem solid can very well turn out not. I found cutting the perimeter of the deck with a dremel made fairly quick work of removing the deck.

Pending the craft foam does account for some structural support. You can use pour type or block. Block foam may take longer to install, but won't absorb water like most two part foams do.

 

[92excel]

Re: When it rains, it...

Question - if after removing the decking the foam appears to be waterlogged / damaged, is the typical action to remove completely, and replace? Is the purpose of the foam for additional structural integrity without much weight or loss of buoyancy?

Yes REMOVE if your foam has taken on any water as it will never fully dry out.. someone here may correct me but thats all up for debate.

you may reuse any dry foam only if the foam provides no structural aid and you choose the block foam method over pour foam method. More then likely your boat does not rely on foam for structural integrity.

if you are going with the 2 part pour foam then most just remove it all and pour all new foam. pour foam can be done before or after the deck is installed. search fuzzywiggler who did a nice thread on how to do pour foam after the deck is installed.

 

[maxumized]

Re: When it rains, it...

Update:

Maxum (US Marine) was kind enough to send me a floorplan (a 98 model, close enough) of the boat briefly describing how the floor was installed.

For anyone who is interseted, please see the following:

http://www.rutledgedc.com/1998_Floorplan.pdf

Here are the notes they included in the e-mail to me:

"The floorboards are laid on top of the stringer grid and the seams are chopped (glassed) together. When the carpet is removed you'll see what I am referring to. We do not have any drawings specifically for your boat in question but I included a drawing of a 1998 Maxum as the process was the same. The floorboards were also stapled to the stringer system and installed while the laminate covering the stringers was still wet, which will most likely cause a minor bond of the flooring to the stringer grid even though the topside laminate has been ground away. There is upright flotation foam underneath the floorboards which also needs to be replaced if removed."


Here's what I gather from all this (correct me if I'm wrong)

The floorboards were laid in and stapled to the stringers. The stringers were still wet with resin on install, so there was a bit of bonding there to begin with. It doesn't appear that the entire floor was glassed; however, the seams were glassed together using strips, or "chopping". Then, the entire floor was resin coated.

My remaining quesiton is... what is the document referring to on the first page with regard to aluminum plate? I haven't come across any aluminum plating since working on the floor... however, I haven't gotten to cut all the sections out, either.

Anyone have any insight or experience here?

Thanks again for the support!

 

[tashasdaddy]

Re: When it rains, it...

it says refer to wood shop drawing, they arrow points to two places at the transom area.

 

[oops!]

Re: When it rains, it...

I think I'm going to replace with pressure treated (marine grade if I can find it locally) plywood and a single layer of glass.

ok......as far as wood...buy it now and start drying it
...you have 3 basic choices......marine grade.....(expencive).....pressure treated....(wet) or ext grade plywood.....(works good).......once the wood is fully encapsulated by fiberglass....it will last longer than the desire to own the boat.

you need a minimum of 8 oz of fiberglass on the top of the deck....(floor)......that can be as many combinations of matt and cloth as you choose......but matt MUST be used first with polyester resin.......

(BTW>>>>>>>there is a good chance your boat is made from VYNAL ESTER resin......known comnly as VE resin.....

VE resins are stronger than poly resin but have many of the same properties.....check with the manufacturer, as the repair procedure will require specific detailes on what type of resin was used, and will in fact dictate what and how you proceed.

is the typical action to remove completely, and replace? Is the purpose of the foam for additional structural integrity without much weight or loss of buoyancy?

yes.......home boat builders/restorers commonly replace foam.
if the foam is a pour in type filling every nook and cranny of the hull.....it is structural.....it must be replaced unless the hull is reinforced from the inside.
block or unuasal shaped foam is not structural.
foam is used to trinforce the hull and provide boyuancy if the boat gets swamped or capsizes.......
the theroy is that the passengers will have somthing to hang on to while they are waiting to be rescued