How I inexpensively replaced my rotten deck (floor)

[71satellite]

Hi everyone,

This spring I bought a 1986 Bayliner Capri 2150 (21 foot) Cuddy Cabin. While I'm not new to working on projects (I own a 1971 Plymouth Satellite and a 1987 Yamaha FZ750), it was my first boat.

The boat had sat at a marina for 12 years when I stumbled across it, and while I knew the floor "wasn't good", and it needed some motor work (there are a couple of other posts in the repair and maintenance section that cover what I did to get the boat running), but I figured for the price I couldn't lose.
Fortunately, I was right. The boat runs like a champ, and looks great (in my opinion) with the new deck.

So, I thought I would share with you the apparently non-conventional method I used to fix (replace) the floor.


As shown in the attached photos, once I pulled up the carpet and cut through the fibreglass skim coat (Note: using the reciprocating saw really cut down on the dust and mess. I initially tried using a grider with a cut-off wheel, but it just created a huge cloud of fiberglass dust), the entire plywood core of the floor turned out to be a soggy mess. I literally pulled it up with my hands like wet cardboard. Most of the floor was being supported by the gas tank!

The tops of some of the stringers were rotten, but were found to be solid a few inches down, so I used them as "anchors" for the subframe I built.

I debated the following floor options:

-Install marine plywood and paint with polyurethane or some other "deck stain" sprinkled with sandy grit for traction
-Cut marine (or regular exterior) plywood and have it encased in a coating of fiberglass (coincidentally I work next to a fiberglass shop and I spoke with them at length about the process)

I didn't want to reinstall carpet, as it seems to me that's half the problem (as it hold water).

In the end, I came up with the option you see in the photos. I used 5/4" cedar deck planks for the decking (flooring), and 2x6' cedar beams for the subfloor and joists.
I'll preface the following description by saying (in case it isn't obvious) that I'm NOT a carpenter by any means! I used a circular saw and a reciprocating saw for all of my cuts, and just did the best I could to get everything to fit nicely.

In the end it was a combination of cost, ease of installation, and ease of maintenance that lead me to my choice. All in all I spent $215 on the supplies to build the floor (including screws!). Since I knew I had to build a subfloor anyways to replace the rotten stringers, I calculated that the total project cost was about half of what it would have cost to use marine plywood, or have exterior plywood encased in fiberglass.


As you can see, the 2x6 subframe is screwed to stringers where possible, and I cut a second 2x6 to fit flush against the hull for further support. Across the gas tank I laid a 5/4" plank to provide something to screw into, and to disperse the weight of people standing on the deck across the tank surface.

It took a bit of finessing around the engine cowl, and in some cases angle-cutting the underside of the deck boards, to get everything to lay down nicely. I also ended up shifting the cuddy door upwards to accommodate the new deck thickness. The problem was that if I set the deck boards low enough to accommodate the original cuddy door height, they would be at too much of an angle to run across the gas tank and meet the base of the engine cowl.

You'll note that at the port and starboard aft corners, the floor isn't finished yet. Thankfully I realized that the original deck surface tapered out and exposes the hull in these corners, so I didn't screw into that. I plan to use construction adhesive to glue boards into those sections. For now it doesn't seem to be a problem.


When I came up with the idea of "building a cedar deck" I researched on the internet and was surprised to find that no one else seems to have tried this solution. The ease of cutting and installing everything "in place" along with the forgiving nature of having individual boards to work with made building the deck very simple. Also, I can pull up and replace a board very easily if something happens. And cedar just won't rot (at least not in the remaining lifetime of the boat).

We used the boat during the Canada Day/Independence Day long weekend (had 5 people on it), and no one complained of splinters. No boards came loose, no boards split, everything seemed to hold up nicely. The deck got soaked numerous times by people getting out of the water, and from the rain that caught us in the middle of the lake, but the deck boards never became slippery.

In hindsight, I should have spaced the boards a bit closer together. I was worried about warpage and swelling, but I think just 1/8" spacing would have been sufficient.
I have debated staining the boards, but as my father pointed out - once you stain a deck, you are forever re-staining. So I think I'll just let the floor weather naturally and see what happens.


Any comments or questions are welcome. I hope this information assists you if you have a similar project.


Chris

 

[erikgreen]

Re: How I inexpensively replaced my rotten deck (floor)

Well, it's creative certainly, and cheap. So I salute your ingenuity there.

Things to look out for going forward: Watch to see that screws don't become loose with vibrations, or with rot proceeding through the stringers. Make sure you allow water to drain out of the bilge, since it's going to be draining straight down off the deck.

Obviously try not to do any jumping of waves or anything that places significant stress on the hull and deck. The stringers aren't there just to hold up the deck, they're a required reinforcement for the hull, so if they're starting to rot they'll eventually finish, and your hull might fail when they get weak enough (IE big crack, then fast sinking).

Cedar decking has been thought of by a number of people for boats... but it's not easy to fiberglass onto, and therefore you can't make a cedar deck part of a boat's structure very easily. Screwing it on will be weaker than fiberglass, especially if the screws or the wood they're in start to corrode.

But if this solution works for you, more power to you. Just be careful going forward since no one here can really predict how or if you'll have problems.

Do let us know periodically how things are going.

Erik

 

[Fingernip]

Re: How I inexpensively replaced my rotten deck (floor)

Pics are too small to tell if you have/had foam in the boat. If so was it wet? Also the deck boards look great but I cant imagine them sealing off from water at all. If what's left of the stringers are compromised and not glassed in it may be disaster waiting to happen. Saturated foam will add allot of weight to the boat as well as help rot any wood under the deck along with your transom. Also in allot of the boats the deck itself is a structural component and helps keep the hull from flexing.

 

[erikgreen]

Re: How I inexpensively replaced my rotten deck (floor)

Actually, in many boats the deck is not a structural component.

That's one major reason why a rebuild where the deck is glassed to the hull is an improvement over the factory configuration.. the whole thing gets stronger as a result.

 

[Andy in NY]

Re: How I inexpensively replaced my rotten deck (floor)

Pics are too small to tell if you have/had foam in the boat. If so was it wet? Also the deck boards look great but I cant imagine them sealing off from water at all. If what's left of the stringers are compromised and not glassed in it may be disaster waiting to happen. Saturated foam will add allot of weight to the boat as well as help rot any wood under the deck along with your transom. Also in allot of the boats the deck itself is a structural component and helps keep the hull from flexing.

He wont have to worry about sealing the deck boards, they are cedar... naturally waterproof.

 

[Fingernip]

Re: How I inexpensively replaced my rotten deck (floor)

He wont have to worry about sealing the deck boards, they are cedar... naturally waterproof.

Its the joints between them i would be worried about. If the boat does in fact have foam that somehow remained dry, it wont be for long. If no foam hes just gotta make sure everything drains to the bilge.

 

[Fingernip]

Re: How I inexpensively replaced my rotten deck (floor)

Actually, in many boats the deck is not a structural component.

That's one major reason why a rebuild where the deck is glassed to the hull is an improvement over the factory configuration.. the whole thing gets stronger as a result.

I did not know that. Do they normally just not glass the deck to the hull at all or just gets enough to seal it? Im wondering if my deck is original in my 4winns now.

 

[jimjomac]

Re: How I inexpensively replaced my rotten deck (floor)

Well, I hate to be the spoiler! You did a fine job, it looks beautiful, but:

Erik mentioned that the stringers are there for strength. Many don't realize that the plywood was also there for strength. Now I'll grant ya that it's a lot stronger than it was with the rotten plywood, but the correct way to do it is with new plywood which has been thoroughly preserved. This means soaking it with penetrating epoxy and glassing it both sides with epoxy resin. Polyester resin is actually hydrophilic, so it does little to protect wood. Same applies to the stringers - they should be soaked with penetrating epoxy and glassed over.

Back to the strength: The skin of a fiberglass boat is very flexible. So is the skin of an airplane's wing, until it's attached to ribs and frames. The combination of the boat's bottom skin, stringers and floor make a very rigid structure. You could make boats with thicker heavier skin, but they'd barely float! And there's no better "shear panel" for a floor than plywood, at least at reasonable cost and weight.

If I had just finished the beautiful job you did, and read this negative post, I would not take it all apart and start over. Rather, I'd take it easy in rough water and keep an eye on the planking. If you keep the boat long enough to see the planking coming loose, and still want to keep it, then I'd consider re-doing it. If it were my job to do over, I'd still use the beautiful cedar planks, but they'd be installed over strength-providing plywood.

 

[jimjomac]

Re: How I inexpensively replaced my rotten deck (floor)

Don't know how double post happened...

 

[erikgreen]

Re: How I inexpensively replaced my rotten deck (floor)

Well, I don't mean to be contrary, but due to mass production efficiencies, very few mass produced boats are built with the deck and hull connected strongly enough to be considered one piece ("monocoque" construction).

Take my '81 sea ray for example. The hull and top cap were molded separately, then the interior structure (stringers, half ribs, bulkheads) was assembled from wood and dropped into the hull as a unit on top of some peanut butter type glue. Glass was added with a chopper gun in places where needed (like the motor mounts), then the deck was stapled down over that and covered with enough glass from a chopper gun to waterproof it.

Small holes were cut in the deck after that and foam injected, which helps stiffen the deck and hull some, but doesn't make the deck structural. Then the top cap was stuck on.

If Sea Ray had built the boat by glassing stringers to the hull, then gluing deck sections to the stringers, then glassing the deck edges to each other and the hull, the whole thing would be massively stronger (like it is since the rebuild). But it would take more materials and much more labor to do. Sea Ray could deal with that by raising the price, but since each model of boat is aimed at a market segment, that's not their goal.

Manufacturers also have to cope with various add-ons and model changes, like live wells or special seating, which affect the deck strength and shape. If they made the deck structural they'd have at least twice the work to do ensuring that there was enough strength elsewhere to compensate for the big livewell or storage compartment hole. Each time a change was made they'd have to re-calculate strength of the whole boat and maybe change the interior structure to compensate. Expensive.

Since instead they made sure the deck is just there to walk on, they can do what they want.

This isn't to say that they don't glass decks on, or that they don't contribute to the boat's strength or stiffness, but for the most part you can do what you want to a deck and the boat will be safe, if a bit uncomfortable to use, as long as the stringers, transom and ribs are ok.

There are some exceptions to this with certain good or high end manufacturers and it's not usually true for boats made in materials other than FRP, but as a generalization for fiberglass mass produced boats it's true.

Erik

 

[keepNitreel]

Re: How I inexpensively replaced my rotten deck (floor)

but the correct way to do it is with new plywood which has been thoroughly preserved. This means soaking it with penetrating epoxy and glassing it both sides with epoxy resin. Polyester resin is actually hydrophilic, so it does little to protect wood. Same applies to the stringers - they should be soaked with penetrating epoxy and glassed over.

That sounds like overkill & not very cost effective. A nicely sealed glass job with the proper mat/cloth will last decades. Keep it drained after each use & covered from the weather & it may out last you.

 

[jimjomac]

Re: How I inexpensively replaced my rotten deck (floor)

Well, I'm a perfectionist, but my belief is it will NOT last decades! It would if you could keep it dry, but that's tough with small boats. A lot (all?) manufacturers are now advertising no wood in their hulls - don't know how they do it.

BTW, I do like eliminating the carpet.

 

[cheesegrits]

Re: How I inexpensively replaced my rotten deck (floor)

Hey 71 first thing don't get mad. This is only my .02. I'll start with one good thing about your fix. I really like the look! It gives me a whole new idea about redoing my Aquasport. This is the bad part. The cap on your hull is now very easy to seperate at any time from the gunwales. I just helped my buddy redo his 1988 1850 Capri's floor. When you spoke of the tapered edge where the floor ran out and the hull was exposed is the strongest link to keep the boat together. My friends floor didn't taper out it ended in a nice beveled edge that sat in a step down that was actually a very strong joint. The hull in this spot was about 3/4" thick. Even with his rotted floor this joint which runs all the way from stern to inside your cuddy was the only thing keeping his together. Without this being in place you IMHO are sitting on a bomb! Be very careful! Large waves are a no no! If it hasn't flexed yet it will! And when it does the caps gonna let go with no warning and you are in deep real quick. Here are some pics of how we fixed his by dropping in coated plywood into that edge and laminating it with biax and epoxy. We also ran wetted cloth across the whole floor and now his is stronger than factory

Like I said don't get mad I just don't want anything bad to happen to you or your family! My .02

 

[keepNitreel]

Re: How I inexpensively replaced my rotten deck (floor)

Well, I'm a perfectionist, but my belief is it will NOT last decades! It would if you could keep it dry, but that's tough with small boats. A lot (all?) manufacturers are now advertising no wood in their hulls - don't know how they do it.

BTW, I do like eliminating the carpet.

Boats from the 60's drained & garaged all there life look like the day they where bought, that would be almost 5 decades. One example appeared on this site recently.

I agree on the carpet, holds water, best kepted in the house not a boat.

 

[erikgreen]

Re: How I inexpensively replaced my rotten deck (floor)

The maintenance a boat receives is far more important to its condition than its age or the amount or type of use it gets.

There are hundred year old all wood boats out there in near perfect shape because the maintenance on 'em isn't deferred, it's done regularly.

Erik

 

[bigredinohio]

Re: How I inexpensively replaced my rotten deck (floor)

The maintenance a boat receives is far more important to its condition than its age or the amount or type of use it gets.

There are hundred year old all wood boats out there in near perfect shape because the maintenance on 'em isn't deferred, it's done regularly.

Erik

I completely agree with the maintenance statement!

This is interesting concept with respects to the deck but I don't think I'd chance losing structural integrity...especially if you're concerned with the boards warping over time.

You will probably end up spending more money fixing any problems (minor or serious) down the road then had you glassed in a new plyood floor.

 

[ondarvr]

Re: How I inexpensively replaced my rotten deck (floor)

WOW, lots of things in this post.

Most plywood floors in small boats are structural, why would they over engineer the rest of the boat when the floor can add a great deal of strength for no more money, weight or effort. It would be nice if it was connected to stringers too, but even if its only attached to the hull sides it makes the structure far more stable.

Pre-soaking wood with epoxy does little to prevent rot, the fact that its been thoroughly encapsulated and stays dry is what prevents rot, how deep the epoxy penetrates is not of great importance. Penetrating epoxies have typically been thinned with solvents to help them soak in deeper. The problem is the solvents reduce its strength and water resistance, plus the difference in penetration is minimal and so are the benefits.

As far as being waterproof, both resins are sufficiently water proof to get the job done, it has more to do with the quality of workmanship and attention to detail. Poor designs and sloppy work, as in unsealed bolt holes, lack of drain holes, wood with no, or too little glass over them is what speeds the rot process, not water migrating through a laminate. It will make no difference which resin is used, if the workmanship is poor, the wood will rot.


Now to the OP, without the plywood floor it will flex more, will it be enough to cause problems.... there's no way to say, but it may depend on how you use it. I don?t think you described in detail how you fixed the stringers, but without the floor there will be more stress on them trying to hold the hull true.

 

[dino35]

Re: How I inexpensively replaced my rotten deck (floor)

I'm a brand new boat owner. It's a 14 ft fiberglass Cardette (Canadian) built around 1965. Unfortunately, the boats been passed around a few times and the owners we got the boat from know nothing about it. No HIN, nothing. Amazingly, the outboard engine works fine, but the floor is completely rotted out. I'm not new to boating, but definitely new to boat repair, and was hoping someone could point me in the right direction for finding a manual, how-to guide, anything for this boat (or in general if that would work too). I don't want to jump into anything, spend the money, and find out I did it wrong (put on carpet, no foam, etc. - clearly these are very big mistakes!). Any guidance would help-out.

 

[71satellite]

Re: How I inexpensively replaced my rotten deck (floor)

Hello Everyone,

Wow, I certainly didn't expect my post to generate this much interest.

I don't take offense at all to anyone's comments - I am fully aware that my solution isn't "ideal". It was something I could do myself, that wasn't expensive, and that looks (and smells) nice. The following shouldn't be interpreted as "me defending myself", but simply my thoughts in response to everyone's input.

Regarding the structural issues - there seems to be a bit of debate on whether the plywood/fiberglass deck (floor) was key to the structural integrity of the hull. I guess my (non marine-engineer) opinion would be:

Considering how thin the fiberglass layer on top of the plywood was, I'd be surprised if it was providing much strength. The plywood, and its attachment to the stringers - yes I can see how that would improve the rigidity of the hull. However, by using 2x6 cedar boards for the subfloor, I think that I have replaced a lot of the rigidity that was lost due to rot. The outer edges of the deck (where it tapers into the hull), and everything beneath the seats/storage lockers/cubbies is solid, so apart from the "T-shaped" area down the centre of the boat that I replaced, there seems to be a lot longitudinal bracing (from bow to stern) provided by the remaining fiberglass and plywood that makes up the floor and storage lockers that hasn't been altered.

Obviously, time will tell. If the boards start twisting and the screws start ripping out, I'll know that there is a lot of hull flex.

And ultimately, I agree that my stringers are going to continue to slowly rot away. Then again - unless I completely removed them and rebuilt them from scratch, they probably would anyways. At least with my "cedar deck" approach, there will be adequate air circulation to dry things out and reduce the likelihood of prolonged dampness (which seems to occur when the fiberglass coating on the plywood inevitably cracks).

The way I see it, if this setup lasts a few years and eventually I have to do a major rebuild - hey I got a few years of enjoyment out of the boat for the time it took (about two evenings) to install a <$250 floor. I don't know anything about laying fiberglass, and don't have the money to pay someone to do it for me.


Lastly, the foam issue. I've been discussing that in another forum actually (regarding max speed at WOT). In the area where I pulled up the original deck, there was no foam at all. Just open space and the large gas tank. The question I have posed is whether the foam sits beneath the driver/passenger seats, under the "storage cubbies/lockers". Those areas were completely sealed off from the area I was working with, so the only way for me to check whether there is foam in there at all would be to drill a hole in the bottom of one of the storage lockers. But then....I'd have a hole in the bottom of my storage locker and wet fenders/anchor lines would drain through the hole.....

Anyways, if someone can verify whether I should be checking for wet foam beneath the seats/storage lockers, that would be great.

Thanks again for all your input. At the end of the season, and perhaps next year as well, I'll try to follow up and let everyone know how the floor is holding up. This past weekend we were wakeboarding, tubing, and generally tearing around the lake for 3 days straight and nothing "bad" happened.

Have a great weekend,
Chris

 

[cheesegrits]

Re: How I inexpensively replaced my rotten deck (floor)

Yes there is foam on the outside of the stringers. There is also foam under the seats. The whole area under the seats in the bow are solid foam. In my friends boat all foam under the sole was soaked through. We removed it all and poured it back with closed cell so it wouldn't do it again. In all we removed at least 200 lbs of soaked foam. The foam in the bow under seats was okay so it stayed.