Floor repair questions - long

[Ed L.]

A few more months and the Bass will be on the nest so I need to get this repair started. I bought this boat last spring and I had pulled the seat out to fix the battery box strap. That’s when I found out the floor was rotted and I went through a couple of places. I proceeded to cut a couple of small holes so I could get the nozzle of my shop vac in and under the floor to get the water out. I managed to get 4 gallons of water out. As you can see in the photos I placed a sheet of ply over the hole locations and screwed it down so I could use the boat last year.

Here’s shot of the interior from front to back. As you can see this is a very simply constructed boat. I am amazed at how strong it is though and the kind of water it can handle. It’s a very stable and smooth riding boat. It’s also a dry boat when running so I’m inclined to keep this one for awhile and I want to fix it right.

Here’s another interior shot. The dimension for the front deck to the spashwell is 7’-7” and the width is 46” so one sheet of plywood is all I’ll need. I’ve been on so many sites with differing opinions I’ll come back here and ask my questions.
1. I used MDO board on repairing the floor in a Starcraft I had a few years ago with great results but that plywood had a primer seal. I don’t think that’ll be good for soaking up epoxy. I carpeted the Starcraft floor and used exterior carpet glue.
2. From suggestions at other boat building sites it seems there is an alternative cost effective wood called AraucoPly ACX sold at Menards and Lowes. It’s suppose to have no or few voids and waterproof glue and keeps it’s flatness well. Has anyone used this?
3. Waterproofing the plywood floor I assume you seal both sides and edges with epoxy. Some places I read say to cover the floor top with 8 oz. of fiberglass and some say to encapsulate the whole sheet. Then a couple I read say cover with epoxy and paint to protect the epoxy from UV. A couple of guys told me, it’s an old boat and using the fiberglass kit at Lowes works just as good as expensive epoxy.
Back to front

I cut a hole in the floor last night to see what I’m getting into. I was pleased to see the stringers although damp are not saturated and rotting. I believe I can dry them out and not have to replace them. I was surprised there is little foam under the floor. Hole in floor

Here’s a shot of the splashwell. I was told I didn’t want to remove this and to only replace the floor between the splashwell and front deck. I was told the rear areas of the splashwell on both sides were flotation pods and under the front deck is a poured flotation area. I guess that’s the reason there is no foam under the floor.
http://i147.photobucket.com/albums/r282/ejlydic/Mitchcraft/DSCN2447.jpg

I was glad to see there was no water in the boat. I had a guy replace the drain tube in the boat last summer when I found out the tube was the culprit letting water fill the boat. He botched the job totally so I pulled the tube out and replaced it with a garboard plug.

under floor – Port side

I’m considering pulling the steering cable out at the helm and detaching everything in the outboard controller when I pull the center console rather than pulling the motor off.

 

[jehler]

Ed, It has been a few years (20 ish) since i was the low man on the totem pole at a full service marina, being the low man bought me the experience of removing and prepping for repair a few boats similiar to yours. I did not do the actual repairs and reglassing back then, just the demo and dirty work but i did pay fairly close attention to the process. pulling the console was the first job. time consuming but usually not difficult unless the wiring was done in an unorginized matter, if it is a shambles now is a good time to re-do it. steering and control cables are all fairly easy. next would be actually cutting out the floor. I would wear a mask and face sheild and use an electric or air powered die grinder with a cut out wheel and try and get as close to the hull as possible without disturbing the outer hull. the back seat, bench area of your boat will be a difficult area as they are molded right in. i think taking them out would be cost/work prohibitive. Unless they were really rotted i would make your cut in the floor an inch and a half to the bow side of them so that you would have room to screw on a ledger to tie in your new plywood. once the floor is up a few flood lights and a dehumidifier help dry things out. any stringers that are showing moisture i would drill a 3/8" hole every 1/4' or so directly down into the top and put a lamp to it to try and dry it out. once dry they would be poured with penetrating epoxy until they would hold no more. rotten areas would be cut out and repaired with epoxy and new wood. once everything was dry and repaired underneath (good time to check out fuel tank, wrun new wiring etc.) we would make a template for the floor with cardboard. attention was paid to get a tamplate for the where the top of the plywood planed in and then shape an angle on the edge so that it dropped into place. areas bigger than a sheet were not scarfed at my place of employment, don't know why, they always just used a wood strip to make a ledger. once it was fit it was tacked to the stringers in a few places with a screw and then glassed in on top. marine grade untreated plywood was used and was glassed over the top. there was no coating applied to the bottom. our service manager said thata coating on the bottom would hold water in the wood should the top get dinged, i am sure there is as many opinions as to how to properly coat the plywood in the floor as ther is leaves in a tree.

i haven't been in the boat business now for 10 years but as a contractor i have experience with auroco ply. it is a decent plywood that we use for built ins and cabinets, it is not though free of voids, it does claim to have a waterproof exterior grade glue, i would use marine grade as your only going to need a coupke of sheets but auruco would probably work.

 

[Mark W]

Hey Ed -

Now I understand your situation. I'm not going to be able to add anything more than the comments up above. I would like to add the importance of a couple of things. Please wear a respirator. A good friends brother died doing similar work due to fumes he inhaled. When in a boat like you will be, and I assume you will be doing this in your garage, the fumes are heavier than air and will accumulated in the hull where you will be working. Before you know it, you are out like a light never to awaken again. Secondly, make sure the wood that is wet underneath is completely 100% dry. We used to be in the coating business but got out of it due to too many people not letting wet wood dry out prior to re coating. This caused the coating to blister and peel and naturally the blame was placed on the big money folks and we spent quite a bit to pay for poor prep.

As far as what I would use. I would look heavily at a nice vinyl ester resin verses an epoxy. Cheaper, easy to use and a very good water barrier. There are many to choose from. You would then have no compatibility issues with whatever you use on top.

Mark W

 

[jehler]

I'll second the vinyl ester resin on the top deck. we used west system only for the repiars below where bonding was critical but on the top decks always regular resin. I remeber a customer arguing with my service manager, he was upset we didn't use epoxy for a fiberglass repair on a small ding on the side of his boat. he spent 5 minutes telling my service manager about the molecular make up of epoxy, the bonding strenght, the elasticity ...... the service manager, an old guy fairly set in his ways, says "hmmmm, that sounds real interesting, but if the last thousand boats I have repaired in the last 20 years haven't come apart yet why do I need to spend a lot more money for a little more sticky?" I still like epoxy for my own builds but more for the conveinence of the longer set times. check a website called us composites for supplies

edit, the drying process sometimes took weeks/months fyi plastic and a dehumidifier help a great deal, as was stated above, very importand to get it dry

i also seem to remeber them using an epoxy caulk between the stringers and deck.... I am sure there is a pro here that knows for sure what it was, might have just been 5200?

 

[Huntindave McCann]

Ed,

Start by removing the center console. Lift it up with a small rope and pulley from the rafters. Pull the hull out of the garage.

Back in a new hull, drop the console back down and you are in business.


Seriously, if you need a hand with the removal and or installation, I might be talked into coming down your way for a weekend, depending upon my schedule at work.

 

[Mark W]

Ed -

Let m know your abrasive needs and I may be able to pick up cheaply over at the company store. Give me a couple of days as the inventory of what's over there changes quite a bit. Same if you need any 4200 or 5200.

Mark

 

[Ed L.]

John,

Thanks for your insight. You brought up a topic that no one else had but one that I had thought about and that was a ledger board around the perimeter. I had thought that I would do that so the new floor fitup would be better in hopes that my fillet wouldn't sag where the new and old met. Others also had mentioned a chaulk between the floor and stringers saying that you wanted some amount of "give" to the floor so the stringers/floor wouldn't be rigid which could break out the hull. I'll have to look into what to use for the caulk. You may be right with 5200 being the material.

You mentioned using plastic. Are you meaning to cover the entire interior at the gunnel to help with the drying process?

 

[Ed L.]

Mark,

3M model 65021HA1A respirator. Is this a good one? I'll make sure everything is dry. I may hit you up about materials when I find out what i need. I did a little checking on the vinyl ester resin. If they can use it in making airplanes and chemical tanks I suppose it'll work for my floor. It seems pretty cost effective.

 

[Ed L.]

Dave,

You know I value your opinion and I really like your idea of lifting the console and replacing the hull over what I'm about to get started on. I don't have a problem working with wood and aluminum but I've never had anything to do with fiberglass. This is going to take some time. I may just take you up on your offer. At least if your over here visiting maybe you can drop by and give some moral support....;-)

 

[jehler]

as far as a ledger around the outside, i have done both, dpending on the severity of rot, construction of the boat and the budget.
as far as being tight, a good question for an expert. even then you'll get opinions im sure. ours were never perfect but trimmed as close to perfect as was possible without binding or burning up too many hours. I'm no expert, like the old service manager used to say, "John, you know just enough to be dangerous" i only worked in the shop for about 5 years before they moved me into sales and then management...... that should tell you something about my skills!

as far as the plastic, we would put the boat under cover, put a dehumidifier in the boat, run a hose out through one of the garboards or other thru hulls, cover the whole deal with 4 or 6 mil plastic or recovered shrink wrap and run a line around the exeterior of the gunnel to seal it in and try to suck the moisture out of the boat instead of just the air. this was in MI in the summer, getting mouiter levels down was always a bear as we didn't have a conditioned shop. on small repairs a halogen lamp for a few days did the job well

 

[Eric Dellamater]

Ed,

I will echo most of the sentiments above, but ask you to re eval your stringers. So many times they are truly rotten, especially near the base of them, in the bottom of the bilge. IF they are sound, great. IF they are possibly a bit less than perfect, the idea of drying them as much as possible (the means mentioned works really well) and then following up with the notion of drilling them out a bit with about a 1/8 or 1/4" drill bit every few inches and then followed either by WARMED epoxy, UNTHICKENED poured in until they no longer soak up any more OR this stuff called CPES. That crap is a bit more expensive, but basically it is a thinned version of epoxy and is supposed to penetrate better given its viscosity. Now some will argue that all it has is more thinning agents thus, once they evaporate then you are left with a matrix that has more holes and little strength, however, given the number of refurbs you see on places like Wooden Boat etc. that are using it, it must have some value. Others argue just using the warmed epoxy will get you about 80-90% of the way there, but a stronger matrix in the end. Now if the stringers are totally fine, great.

Remember this about fiberglass, you can screw up royally, just grind it back, fill in some gouge and sand down again to try it over and over until you get it right. No big deal. Then paint...it will all be hidden.

 

[Ed L.]

Thanks Eric. I watched a guy in Florida repair a transom with CPEC. He had a soft Transom on a microskiff. He drilled 3/8" dia. holes down into the transom every couple of inches. I think his bit was 12" long. I thought he was crazy I'd never heard of this but after several weeks in the sun he could step up on the lower unit of his boat and jump up and down with no noticable movement at all. He didn't even try to dry the transom out. All he did was let it sit about 3 or 4 days in the sun before he poured. I don't think I'd trust it if I had a couple of 225's hanging off the transom but I'll bet it would be fine for say a 50hp or smaller.

 

[John D.]

Allow me to throw my two cents in,,,I've replaced a few floors, transoms, etc,,,,,I've put a few years in at the boat yard,,,and my period button on my computer doesn't work and for that I apologize,,,,,,All the information in the above posts is great,,,,I totally agree that you should use vinyl ester resin,,,the stuff will hold up great and save you a bunch of cash,,,I also agree that you should investigate your stringers for rot,,,it would be a shame to put a brand new floor on top of some rotten stringers,,,You should at least remove your console and cut that whole section of floor out, and if it was my boat I would cut the whole thing out including the flotation pods,,,The rest of your floor is bound to be rotten and if your going to invest the time and money into replacing a small section you had might as well replace the whole thing and have a brand new boat that will last you a long time in the end,,,you could rethink the layout of your boat,,,,you might find that the space you gain from removing the pods is quite nice,,,and if not you could probably glass them back on,,,,As far as a ledger goes,,,I think you could go either way,,,,I probably wouldn't use a ledger, (if you do make sure you seal it well), I would use a die grinder to cut the floor out as close to the gunwales as I could get, sand the gel coat off the gunwales a good ways up the boat, then make templates,,,, lay the wood down and attach it to the gunwales with a nice thick fillet of resin thickened with cabosil,(this would a be a good time to use epoxy),,,sand the resin after it cures and then cover the deck with glass,,,run the glass up the gunwales where you've removed the gel goat, let the floor float on top of the stringers, there it is, a floor,,,,,

Now what to use for the floor? Advantec, the stuff subfloors are made of these days,,,It's under $30 a sheet,,,practically waterproof,,,,,no voids,,,,,the boards a pretty darn straight,,,it's 3/4in and tough as hell,,it's strong enough to be a floor without any glass support,,,and glass sticks to it great,,,,I love this stuff! Cut the boards,,,,then paint the undersides with bilgecoat,,,,The only draw back to using this stuff I can find is the weight,,,it is heavy, but when using it in a powerboat like yours you'll never notice any difference,,,,I've used this stuff to build floors in several boats and a bunch of transoms,,,I replaced the floor of my 17' Scout with it 6 years ago, sold it to a buddy of mine and it's still in great shape,,,I built a modified Duck Hunter II 4 years ago using this stuff for the transom and all the bulkheads,,,,It's holding up great,,,,,,I highly recommend using this stuff,,,,

This project really isn't as bad as it may seem,,,,,the steps will go pretty quick,,,,,I think cutting the whole floor out and starting from scratch might actually be easier than trying to piece the old floor and the new floor together,,,,Your going to have a new love and appreciation for your boat, (as well as an understanding of how it's put together and works),,,,it will be a great experience,,

Good Luck

 

[jehler]

A little more on the cpes epoxy, the cpes acronym is new to me but the product is not. I have extensive experience with both git-rot brand and also more recently the west marine (not west systems) penetrating epoxy. I use the epoxy on a somewhat regular basis to repiar wood trim and mouldings on older houses where the homeowner is more inclined to save the old, large, hand hewn trims and mouldings rather than tear them down. while the epoxy may not be as strong as an unthinned epoxy i can tell you that (dry) dryrotted wood that has been soaked with the stuff is tougher and harder than the original wood once the epoxy has cured. very messy stuff to work with and somewhat pricey but relative to the alternative it is very cheap. I would be happy to explain the process if you need help, shoot me a pm and I'll give you my phone number if your interested

 

[Eric Dellamater]

one last thing Ed, I agree with the comment above about NOT coating the back side, just the top. You know as well as I do, the top will eventually get dinged with something, water will get in the wood, and if the bottom is coated, no way for it to get out. I would also put in a deck plug thing, those black screw out/pry out 6" wide deals one up front and one in the back type deal (unless you already have good ventilation) so that in the off season or extended periods of non use you can pop them open and get air down under.