Weak fiberglass in sun deck on 340 Sundancer

PicoPico

PicoPico

New Member
Jan 10, 2011
75
Morrocoy, Venezuela
Boat Info
340 Sundancer
Engines
Twin Merc 7.4 MPI EFI
Hi, I have a 1999 340 Sundancer and noticed that the fiberglass area between the windshield and the sun deck hatches (both hatches) on the sun deck are weak and bend down as I step on, the rest of the deck is pretty solid.

I would like to make this area stronger as this is a common area to walk on and I feel it will worsen overtime

Any suggestions as how this can be fixed?

Many thanks,
Pico Pico
 
Sounds like the core is wet. The windshield attach hardware may not be sealed or need resealing and causing water to get in the deck core in that area. I have seen this talked about on some Sea Ray models. Is the deck just flex or does it feel "soft" in the area your talking about?
 
You have a rotted / wet core issue. Very likely, one or both of the hatches needed to be re-bedded some time ago, and have been allowing rain water to enter the coring. Confirmation can be had by pulling one of the hatches, and examining the coring. It sounds like it is probably at the point where you need to replace a section of deck coring, and that is not a simple repair. If done from the outside, the outer deck skin will have to be cut away, the coring replaced, and then the deck has to be bonded back down, along with associated structural and gelcoat repair. Another option is to remove the headliner and trim panels from the interior, and perform the repair from the inside. The method is the same - cut away the skin, remove the rotted coring, and then replace with new coring. The skin is then replaced, and structurally bonded back in place. Then replace the interior.

In any case, if you allow this to continue, the rot will slowly spread, and the soft spot will get ever larger, until proper repair is completed....

Dale
 
MasterFab said:
You have a rotted / wet core issue. Very likely, one or both of the hatches needed to be re-bedded some time ago, and have been allowing rain water to enter the coring. Confirmation can be had by pulling one of the hatches, and examining the coring. It sounds like it is probably at the point where you need to replace a section of deck coring, and that is not a simple repair. If done from the outside, the outer deck skin will have to be cut away, the coring replaced, and then the deck has to be bonded back down, along with associated structural and gelcoat repair. Another option is to remove the headliner and trim panels from the interior, and perform the repair from the inside. The method is the same - cut away the skin, remove the rotted coring, and then replace with new coring. The skin is then replaced, and structurally bonded back in place. Then replace the interior.

In any case, if you allow this to continue, the rot will slowly spread, and the soft spot will get ever larger, until proper repair is completed....

Dale
Click to expand...


What he said.

Pull the closest hatch out of the boat and see if you find a mushy mixture similar to that of oatmeal. If so, that is what's left of your end grain balsa core.
 
thanks to both! I pulled both hatches a few months ago and noticed some wood resin (redish and very solid!) coming out between the hatch and the fiberwork but no signs of wetness at all, having said that, I am the 3rd owner so it might have been wet in the past as , I was wondering that if the core is not wet at all if I could get some of those foam fillers and spray it into the cavities between the in and outer deck? as I can see a hectic bill coming to to that massive job!
 
also, it does seem to be a manufacturing (weak structure) issue rather than water getting into it as both side perfom exactly the same way, it would be too much coincidence.

also, if water were to get into it via the hatches; I would expect the weakness to also be all around de hatch and interestingly the weakness is only above the hatch (if that makes sense)
 
Foam is not the answer.

You might get a surveyor to bring his moisture meter around and check for current moisture.

Other than that, drilling some pilot holes in an inconspicuous place to see if you have water might work. A leak around the windshield that allowed water into the core sounds more likely than the hatch since you have had the hatch out recently.
 
I can reach the area through the cealing lamp in the galley and check for moisture I guess the question remains what if it is all dry?




mistercomputerman said:
Foam is not the answer.

You might get a surveyor to bring his moisture meter around and check for current moisture.

Other than that, drilling some pilot holes in an inconspicuous place to see if you have water might work. A leak around the windshield that allowed water into the core sounds more likely than the hatch since you have had the hatch out recently.
Click to expand...
 
Let's see if some other 340 owners chime in here and report the same issue.

The end grain balsa is sandwiched between two layers of glass and that gives it strength. I am not sure how frequently those layers separate if they are not/have not been wet.

Don't take this the wrong way, but, are you a BIG man? Big enough to make the deck flex abnormally? :huh:
 
An examination from inside the boat through the ceiling lamp won't tell you much - you'll just be feeling the inside fiberglass skin, and it's very likely dry. I hate to say it, but if it's that soft, it got wet at some point, and the coring is compromised. Rick makes a good point - test with a moisture meter. But, again, since it IS soft, something happened.....

Dale
 
Even if the meter shows dry now, like Dale is saying, something happened because the factory probably didn't build it that way. Some test holes big enough for a couple of core samples might be the only way to tell.

I hear tell some folks have had success drilling lots of small holes, injection filling the void full of West System through the holes and then patching the zillion holes they drilled.

A few dollars spent on a good fiberglass guy (like an old fiberglass guy) who has been around for awhile might be your best ally to see what the problem is.
 
Master fab is 100% corect with his evulation of problem the deck must be opened uptop or bottom you cant pass a survey with that and will only get worse till it caves in.
 
thanks to all,
Rick, I would say I am of an average size, but just to be clear, it is soft but not in a way that will keep you awake at night, it is just an area that is not as hard as the rest of the deck, I would be more suspicios of water leak if this was only on one side but it is on both sides and they are far apart but incredibly the same feel in both cases and the "extend" of the both areas are exactly the same, this is why I question the materials, It is one of those anoying things when you want everything to be perfect!:smt021
 
The balsa is like a sponge, if it gets wet, it spreads. Once the balsa gets wet, it starts to decay even after you stop the leak. I know on some Sea Rays, the deck is broken up into sections with a fiberglass barrier between to stop the water spread if one section gets wet. regardless, you need to pull all of you hatches and port holes and re-bed them, you're past the due date if they haven't been. You need to get someone with a moisture meter on the boat and try and map out the damage. This will tell you what actions you should take. If it is wet, the only real cure is to re-core. All other remedies are just temporary fixes and will ultimately make the re-coring job that much harder. Approaching it from the inside is a HUGE job and messy beyond description, but is doable especially if the boat is in need of an interior makeover. Good luck.
 
If you can get someone with a meter, do so. It is always best bet. But if you do decide to go after it, I would do it from inside. I just did the interior on mine. My boat is older than yours so the structure maybe different. I did have a leak that caused the headliner to get wet and moldy. In that area was just dead air space and no core. There is a structural piece the was in tack near there. I did drill some 1" holes in a few areas so I could reach in with a snake camera. It was clear there never was coring in that area. So to stiffen it up, I expanded the area where the the weakness was and used 404 with the epoxy to create columns of reinforcement. Then glassed the underside where the major holes were.
 
Thanks Guys, very much appreciated.

On closer inspection this weekend; we noticed that the previous owner already drilles some holes to fill with epoxy! hence the redish resin I mentioned earlier.

Anyway, I took a the fiberglass guy to look at the problem, we both feel that the best way to tackle the issue is to peel off the top (from the joints between the non slip areas so we can keep the top intact and original and re use it, re-core from the outside; we will use a plank of PVC called honeycom system that someone from the auto industry recomended, it seems to be easy to shape and best of all it will never rotten again!

Now, we decided to go from the outside to avoid all the mess in the interior, despite being almost 13 years old she looks almost like new al around!

I guess the question remains if the best way to do it is from the outside?
 
Yes, it's the best way. They make a new synthetic coring cut in cubes like the original coring. Super easy to lay in and won't rot.
 
PicoPico said:
Thanks Guys, very much appreciated.

On closer inspection this weekend; we noticed that the previous owner already drilles some holes to fill with epoxy! hence the redish resin I mentioned earlier.

Anyway, I took a the fiberglass guy to look at the problem, we both feel that the best way to tackle the issue is to peel off the top (from the joints between the non slip areas so we can keep the top intact and original and re use it, re-core from the outside; we will use a plank of PVC called honeycom system that someone from the auto industry recomended, it seems to be easy to shape and best of all it will never rotten again!

Now, we decided to go from the outside to avoid all the mess in the interior, despite being almost 13 years old she looks almost like new al around!

I guess the question remains if the best way to do it is from the outside?
Click to expand...

I was chatting with a glass guy the other day and he told me two things I never thought about:

1. If you have to open one up from the top, you don't necessarily have to put back all of the non-skid. You could grind some areas flat that previously had non-skid.

2. Someone makes a non-skid mold (think stamped concrete) that can be used to restore/match non-skid.

If you can deal with the patching of the deck, the from the top is way easier to do.
 
fantastic! so we are on the right track! I have ordered the honeycomb planks so as soon as they arrive we will get moving with the job! I will take some pics and post them for someone else's future reference.

Many thanks to all!
 
Any updates on this?

I've got/might have a similar situation where just between the windshield and the port hatch there is a soft spot. Could just be I'm 220lb, or could be the windshield needs a re-seat. Did find some very small, not deep, soft patches when re-seating the hatches - all dug out, treated and epoxied.

How difficult to re-seat a windshield?
 
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