swim platform rot discovered.....

[CliffA]

while swimming behind the boat this past WE a friend discovered some rot under my swim platform on both sides where the deck drain through-hulls are located......the pic below is not my boat but it shows the section of the platform that has some rot.....the rot is located directly beneath the deck drain through-hull in the section of the platform support that attaches to the transom of the boat (see the arrow).....there are no other areas that show signs of rot....

my question is how serious is this and what steps do I need to take to get the rot out and to stop it from spreading?...

thanks...

cliff

 

[BillK2632]

So it looks like there is a backing plate glassed into the swim deck where the bolts that hold the swimdeck on attach - obviously made of wood. My guess is where the cutout was made for the drains was not sealed very well or just failed over time. Probably some flexing going on everytime someone is on the swimdeck. If that is the case, it looks to be a matter of cutting that area out and replacing the backing plate and then re-glassing it. Good news is it's not visible so the work needs to be structural but not so much cosmetic. The next question is if it can be fixed in place or does the swim deck need to come off and of course the boat would need to be hauled. Don't think you could or would want to take the deck off with it in the water. Once you have access to it I don't think the repair should be too bad. I bet that thing is bedded with 5200.

 

[rcknecht]

Now you got me thinking... If I were you I would not worry about until you pull your boat for the season, and I might not ever worry about it...

 

[BillK2632]

Yeah, would be good to see a picture of your actual boat - if the rot is not around any of the screws and just on the area right under the drain - you could probably just cut the rot out and epoxy the exposed wood and paint it white. If I did this (and I only would if the rot area was really that small and had no impact on the integrity of the area the bolts are in), I would think about putting two aluminum backing plates for the screws on each side.

 

[fwebster]

Don't 1/2 way fix it. The plywood in that area is structural to the swim platform, but the repair would be easy. I would probably wait for the first opportunity the boat is out of the water then remove all 4 mounting bolts in that pocket, grind the entire plywood block away and replace it, then glass over it, brush on some white gelcoat and sling a little blue/black at it with a smallish paint brush to copy the factory finish and go boating.

 

[Steve195]

Are you saying there is rot on the swim platform itself, or on the transom behind the swim platform? Pictures would really help here!

 

[CliffA]

thanks for the replies gentlemen.....

I don't have plans to pull the boat any time soon unless I need to address this issue.....can I afford to wait another year or so to make the repair?....if so is there anything i should do now to stop the rot from spreading such as applying silicone to the area to keep the water out?

I will try to take some pics of the actual rot on my boat this WE.....

thanks....

cliff

 

[Lazy Daze]

It'd be hard to say if the repair can wait. It all depends on how far along it is. Although it's unlikely to be a "gotta do it right now" thing. You could drill some drainage holes, then apply heat and try to dry everything out and then use something like GitRot. That could provide a level of fix anywhere from non-existent to somewhat to permanent. But honestly, you'd spend about as much time doing that as you would just doing it right to start with.

This would be a great glassing job to get your feet wet with. It's really no more challenging than replacing a gas tank in a 215EC.

One thing I like to do, especially on a repair like this, is to saturate the repair plywood with epoxy before putting in place. This entails a few coats as the wood soaks up the epoxy, giving extra attention to the edges (even using thickened epoxy there after a few coats). You can also overdrill the bolt holes, fill with epoxy, then redrill. The wood would essentially be waterproof.

Tools that will make cutting out the glass easy... A grinder is great, but might might a little too big to get in there. But it would make quick work of any leftovers. An oscillating tool with a cutoff blade or even a Dremel will be very handy.

 

[CliffA]

It'd be hard to say if the repair can wait. It all depends on how far along it is. Although it's unlikely to be a "gotta do it right now" thing. You could drill some drainage holes, then apply heat and try to dry everything out and then use something like GitRot. That could provide a level of fix anywhere from non-existent to somewhat to permanent. But honestly, you'd spend about as much time doing that as you would just doing it right to start with.

This would be a great glassing job to get your feet wet with. It's really no more challenging than replacing a gas tank in a 215EC.

One thing I like to do, especially on a repair like this, is to saturate the repair plywood with epoxy before putting in place. This entails a few coats as the wood soaks up the epoxy, giving extra attention to the edges (even using thickened epoxy there after a few coats). You can also overdrill the bolt holes, fill with epoxy, then redrill. The wood would essentially be waterproof.

Tools that will make cutting out the glass easy... A grinder is great, but might might a little too big to get in there. But it would make quick work of any leftovers. An oscillating tool with a cutoff blade or even a Dremel will be very handy.

thanks Dennis....this WE I'll poke around with a pick to see how far the rot has traveled and take some pics....I'll report back next week with my findings.....

cliff

 

[fwebster]

Your goal with this fix is to repair a structural piece that is compromised, not just making rot go away. Your concern should be what happens when you are overcome from the rear with a big wake or wave that causes the swim platform to get some upward force on it. I can see where you could easily do more damage that would put you in the "remove the platform from the boat and rebuild the entire front edge business" if you try to patch it instead of fixing it right. From your photo this will be an easy repair to do correctly on the boat if you do it soon.

Not to get bogged down with semantics here, but when I say "grinder" I meant an air sander with a 24 or 36 grit hard disk on it. Any tool that will allow you to control the depth of cut will work....even a cordless drill with a 4" sanding disk will do, but it might take a while.

 

[Lazy Daze]

Frank - my post about "grinder" wasn't related to anything you said about a grinder (in case you thought it was). I was thinking more about a cut-off "grinder" to get the bulk of the material off (slicing it off). But I'm not sure if you can get all the way into the upper corners. And then use it (or a sander/grinder) to smooth the surface (with a gentle tough, of course). Heck, there's probably a dozen ways to do this!

 

[CliffA]

thanks again gentlemen.....I'll make this more of a priority now.....

this will be the first time I will have the boat out of the water since I purchased it almost 2 years ago.....what all do I need to check / replace while it is out of the water?......i know bottom paint is on the list....I am very familiar with outdrive maintenance but inboard drive lines are new to me......

I may even use this opportunity to increase the size of the trim tabs as many other 340 owners have done....

thanks....

cliff

 

[BillK2632]

I can't speak to the inboard drive line maintenance / inspections you should, but would guess inspection of the cutlass bearings and addressing any issues with props, shafts etc.

Zincs.
Also anything regarding thru hulls or transducers.
A good waxing down to the waterline, much easier when it's of the water.
Touch up the waterline with bottom paint.
Anything with the boot strips.

 

[fwebster]

You are about to discover one of the great things about inboards/v-drives...........They are nearly maintenance free as far as stuff under the boat.

When you haul out always pressure wash the bottom to get it clean, check for blisters (easy to see on a clean wet hull), check the condition of the bottom paint and repaint from the boot stripe to the chine to make the boat look new, check the condition of the anodes and replace the ones you cannot easily get to in the water, check the condition of the props, check the tightness of the prop nuts, check the cutlass bearings, check the trim actuators or cylinders for leaks, check and patch the boot stripe (if you have some matching stripe material), check the exhaust outlets to be sure they are secure, and clean/wax/polish the hull.

I have learned that an annual haul out saves me money so I schedule it in Feburary when we are about ready to begin our Spring cruising season. By routinely checking the running gear most of the above is mostly done on a walk around and takes me 15 minutes. From there, I make a list of what needs to be done and who I need to call (like the detailer, the prop shop, or the service department at the marina for stuff I can't or don't want to do myself).

 

[CliffA]

thanks.....sorry for the newbie type questions.....

what do I look for regarding the condition of the bottom paint?.......if I cannot see the barrier coat does this mean the ablative coat is still OK for another year or so?.....I assume the barrier coat is a different color than the ablative coat....

do I just purchase a gallon of black ablative paint and paint from the boot stripe down to the chine with a small paint roller?....do different kinds of ablative paint play well together or do need to be careful and use the same type that is on the boat now?......

how many anodes are there and where are they located?.......what type anode should I use for freshwater?....is there an anode kit that has all I would need?

 

[BillK2632]

Bottom paint: On mine the barrier coat was a lighter grey than the bottom paint. The bottom paint on mine always got scuffed up some from the trailer and tended to wear more at the chines and keel, so that is mainly where I touched up. Mainly I was just freshening up the bad looking spots. A quart of paint lasted me the whole 5yrs I had the boat. Just applied it with a small roller and foam brush. I knew what kind of paint was on mine, so mixing was not an issue, but I think the general rule is softer paints can go over hard but not visa versa. So in your case you should be fine to use an ablative, pretty sure that is what is on it, but even if not you would be ok.

Blisters: They will be obvious if you have any, I doubt you do. I would cross that bridge if you find any - my opinion is a few small ones on a 15yr old boat, the treatment would be worse than the illness.

Anodes: Definitely a hull anode on the transom, one on each trim tab (in 5yrs mine never saw much activity and never needed replacing) and maybe on the shafts and rudders. I would guess they are aluminum and have probably never been changed with the boat on LKN. If it were me I would change them all at this point. Maybe check with SeaRay to verify which ones.

 

[fwebster]

On bottom paint, one of the reason to pressure wash, aside from getting the algae off the bottom is to get a good clean surface to examine. Look for small pock marks where t he paint is gone, look for peeling and watch the pressure washer to see if any paint comes off. As far as compatibility, this is one of the difficulties with used boats........ you never know what paint chemistry is on the boat so, as a result, you cannot be sure that whatever you apply will work over what is there. It is sort of a gamble. You can probably look at one of the good paint company's websites for compatibility charts. Generally the more expensive ablative paints are compatible with most other high end ablatives. Here is an Interlux Comapatibility Chart:

http://www.yachtpaint.com/LiteratureCentre/antifouling-compatibility-chart-usa-diy.pdf


Barrier coat: How do you know you have a barrier coat? If you do, most epoxy barrier coatings are light in color and easily discernable from black. In freshwater, algae usually grown over the ablative bottom paint and effectively insulates it, so I really doubt you have enough wear to warrant painting more than the waterline to the chine for cosmetic reasons. A quart does my 45 ft Sundancer so a gallon for your boat is overkill. If you do have a barrier coat and a few bare spots, don't sand into the barrier coat, just lightly scuff it.

 

[CliffA]

you are right Frank, I don't even know if I have a barrier coat...I just thought that was standard practice before applying ablative paint....

so basically the algae growth that is robbing the performance of my boat (different post) is the same algae that is protecting my bottom paint from wearing off...

funny how things can be good and bad at the same time....

I like the sound of probably just needing spot painting instead of a full bottom paint job...the Admiral has some travel plans for us later this year and spending money on the boat was not going to fit in well with those plans.....

Bill, I'll just get you to look things over with me when the boat is out since you have some experience.....

cliff

 

[Lazy Daze]

Cliff, there's a chemical etching that can done (as opposed to physically sanding) to the gelcoat to prepare it for bottom paint. This is a pretty popular method and the color of this "etching" often resembles a light gray color, but it is definitely not a barrier coat. I can tell you that your boat would not have come from the factory with a barrier coat, anyways. What's been done since, though, is anyone's guess!

 

[BillK2632]

Bill, I'll just get you to look things over with me when the boat is out since you have some experience.....

Be happy to. I think other than your swimdeck and some anodes due for a change you will find things in surprisingly good shape. Your boat lives a nice easy life in that covered slip in that fresh LKN water.