Soft Deck, What Would You Do?

[noleaclover]

I'm living the dream like the rest of you. Working on my 1999 340 with this same situation on Starboard forward hatch. Cleaned out most of the rotted balsa and have been looking for ideas. Thought about either doing what you did with balsa or using Injectadeck by pulling corner of headliner if needed, drilling holes and injecting the foam. Your pictures and write-up is much appreciated. One note, the port hatch is perfectly dry while the Starboard is wet. Looking at the hole cut for the hatch it is painfully obvious the *person*(insert favorite other word here) cutting the hatch holes simply cut the starboard side too large which caused the screws to pull loose (no holding material) and allowed the hatch seal to leak. What a shame a "people problem" causes an otherwise good boat to have a leaking issue which could have easily been avoided.

I had a friend with a 99 340 who ended up selling it because his deck started getting soft spots. He had a leak on the port side deck window when he 1st purchased the boat and fixed it but it was too late. After he sold the 340, the new owner was at the same marina and last I heard the whole deck started getting soft. It seems to be a common issue on the older 340s to get soft decks due to either windshield screws or hatches leaking.

If I were you and the deck is soft in a big area, I would go from under and cut the balsa and replace the wood. I'd try to avoid doing anything from the top unless you have a good gelcoat guy.

 

[markhpc]

I had a friend with a 99 340 who ended up selling it because his deck started getting soft spots. He had a leak on the port side deck window when he 1st purchased the boat and fixed it but it was too late. After he sold the 340, the new owner was at the same marina and last I heard the whole deck started getting soft. It seems to be a common issue on the older 340s to get soft decks due to either windshield screws or hatches leaking.

If I were you and the deck is soft in a big area, I would go from under and cut the balsa and replace the wood. I'd try to avoid doing anything from the top unless you have a good gelcoat guy.

When we were boat shopping last year (and the year before), I can't tell you how many boats I looked at with signs of moisture in the deck. Probably 90% of them, and I looked at 40+ boats. In fact the only boat I can remember that showed zero signs of moisture anywhere was an old 70s/80s Chris Craft 42 Commander. That thing was bone dry but it wasn't quite what we were looking for. I ended up buying my 3970 because it was one of the few express boats I checked out that had seemingly dry stringers/bulkheads and relatively contained moisture in the deck. Not perfect, but manageable. I suspect a lot of people have elevated moisture somewhere in their deck if they haven't resealed their stanchions/hatches in the last 10 years. They just don't know it yet.

 

[viper340]

markhpc, thanks for the moisture meter link, just ordered.

 

[markhpc]

markhpc, thanks for the moisture meter link, just ordered.

No problem. Be aware that metal can screw up the readings, so if you see a sudden spike you might be going over a metal plate or something. Usually if there's water you'll see a gradual gradient change where the moisture level increases over 1ft span or so. Also I wouldn't worry about the specific number you see on the screen, it's more the change you see over an area. My meter and my surveyor's meter were calibrated differently so would show different numbers, but the ratios would often agree with each other (30 on mine = roughly 15 on his, 60 on mine = roughly 30 on his, etc).

P.S. If you hit a void (potentially due to the balsa rotting away to nothing!) you may not measure any moisture either!

 

[boatman37]

Some bottom paint will also throw readings off. Mine showed higher readings everywhere there was bottom paint but after percussion testing he was satisfied it was fine.

I have a similar moisture meter but didn't take mine with me when the surveyor was there. His was an analog gauge. He said he liked them better. Mine is a General brand and looks almost identical to yours but mine has 4 selections for drywall, concrete, hardwood, and I think softwood. My swim platform is rotted and sitting in my garage. I ran my meter over it and in about 90% of it I get high readings. And about moisture...I have a soft spot about 16" in diameter but I drilled test holes and I have wet wood almost the whole way across

 

[viper340]

When I purchased the boat it had been surveyed and all was good except the starboard foredeck hatch area so I was aware of the problem and figured repairing it would be possible without cutting the top deck out. I have removed almost all of the rotted balsa and will use the moisture meter to ensure I have it all out and the rest of the area is ok. I may also run it over some other areas but they should be fine....I hope Thanks for all the notes and comments.

 

[viper340]

Update. I bought the Injectadeck big boat kit and went to work, it works exactly as advertised. I talked with Chris twice, once before buying and once after buying. He answer the phone both times and provided complete instructions on how to extend the tip with a plastic hose that is taped to a stiff, steel rod every two inches so I could inject between the topside fiberglass and ceiling sections at the removed hatch opening. This means I did not have to drill holes topside or from underneath. It takes preparation and is easier with two people although I did it solo. You need to get a feel for how much comes out with each trigger squeeze so you can estimate how much to pull back on the hose each time. They suggest holes every 8-12 inches so you can use this information to help with withdrawing the hose. The foam does dry in a few minutes so you need to get all spaces starting with the furthest away and moving toward the hatch opening. As noted, my boat is a 99 Sea Ray 340 and I did not suffer from any deck warpage due to foam expansion. ONE NOTE: There was a slight warp at the hatch opening but it was my fault because I added too much Injectadeck in that area and did not reform before it hardened. Because the opening had no support it grew about 3/16 of an inch for about a 2 inch horizontal area. Once the hatch was replaced and the trim installed it is not noticeable at all. I could have easily avoided this small issue by adding small strips of wood sized for the opening and taping the top and bottom together. This would have also kept the Injectadeck from oozing out. Keep in mind Injectadeck is dispensed as a liquid so put plastic sheeting everywhere, check your work and then add two more layers The starboard foredeck is now solid, particularly at the hatch opening area. I noticed a slight flex toward the bow if a few areas but nothing that seems soft. It is likely I did not get a complete coverage in those two spots. Someday I may take down headliner, drill a few holes and add more foam from underneath but truthfully I probably won't bother because it is solid and you can jump on it if you want. I did miss a spot toward centerline but a small portion of the headliner was already down by the hatch area so I drilled a few holes on the underside and added the Injectadeck. It did not take much and I was done. Re-glued the headliner back up and all good. I have seen a lot of threads saying the only way is to remove the deck, add balsa, etc., etc. I can understand someone trepidation with Injectadeck but the truth of the matter is it works just as advertised. You can now walk on the boat foredeck and it is perfectly fine.

 

[Bolfer]

This is a great thread! Great ideas for fixing a wet deck section.
It also makes me frustrated w Sea Ray - and apparently most builders. Could Sea Ray have simply taken about 10 minutes during the build to seal the cut edge of the deck hatch openings with some kind of resin or epoxy ... and eliminated a major source of water intrusion into the deck core? This is a standard for limber holes etc. Seems like a simple step for a major benefit in durability, quality, and reputation- why would they not do this?
And... if re-bedding a hatch on an existing boat, maybe grind in the balsa 1/2 inch or so and fill with an epoxy?
Another thought - maybe a good idea to buy a moisture meter and check the hull every year, catch problems earlier.