How to Detect Bad Stringers

[tomelenbaas]

All these threads about stringer replacement have me worried. My '88 Mariah appears sound - engine mounts are all solid - but I have had some rot in the floor under the captain's chair and I do have a small soft spot in the floor near the port-side of the engine box. I removed the rotted wood under the captain's chair and replaced it with plastic marine lumber about 4 years ago. At the time the bad wood appeared confined to about a 1 square foot area immediately under the captain's chair. I have not yet done anything about the soft spot near the engine box.

Is there a way to check the integrity of the stringers without tearing the boat apart? The fiberglass in the engine compartment is in good shape - no visible chipping or cracking.

[Okie Boarder]

You can try torquing your engine mount bolts. You can also see if you can torque any other screws or bolts attached to the stringers for peripheral devices. I've heard you can tap on them with a hammer and listen for it to sound solid or hollow. I'd imagine you could do a couple test "core" samples too. I'd bet you could take a 1" hole saw and drill into the stringers in a couple places to see what the wood is like. You could do it with a smaller bit, too and just look at the wood shavings on the bit. Then just fill the holes with epoxy and maybe a filler of some sort. I'm sure others will chime in with ideas, too.

[87SunSportMikeyD]

" You could do it with a smaller bit, too and just look at the wood shavings on the bit. "

This is the best idea I have heard.

[Okie Boarder]

Got referred to this (http://www.freewebs.com/billsboatworks/) site as a cool reference for rebuilds. This was on there and I felt it was applicable...


How to Check for Water Damage in Your Boat The indicators can be subtle, such as engine mount bolts that do not tighten or severe such as violent shaking when putting the boat under power. Here is a list of some of the common indicators:

o The bolts that secure the engine mounts to the stringers do not tighten

o Visible cracking between the stringers and bilge, hull, or floor

o Soft spots on the floor

o Visible damage and/or exposed rotten wood

o Vibrations while accellerating when the engine and driveline are properly aligned

o Soft spots, corrosion, or cracking around through hull fittings

o Damage below the water line that penetrates the hull

One way to check is to use a No. 2 cross tip screw driver, an ice pick, and a hammer. Hold the screw driver by the tip and bang the handle along the stringers and floor. You will be able to discern between damaged and undamaged material by feel and sound. When you find a suspect area, try to poke the ice pick through the glass. If it goes right through then you have confirmed that there is water damage to that location.

[snibbornairb]

I have the same boat, and the same problem w/ the chair. The wood support under the sole completely rotted out and contaminated the secondary smaller stringer. There is also one of these supports (3/4 ply about 6" wide running from the main stringer to the wall) next to the engine box. These pieces were poorly (if at all) sealed from the factory and caused my damage.

[Salty87]

tbaas

you've got something that will only get worse with time. those are some of the usual signs. drilling is probably the best suggestion. taking a hole saw and opening the floor (under the observer's seat) and then removing the foam will tell you if the foam is wet. you can get a look at the main stringer too. you can buy a plastic access cover for about $10 and leave the access hole.

if the foam is dry you can fix spots. if the foam's wet, it has to come out. it will never dry...the rot will keep spreading too.

i'll drink a beer for your boat tonight ;)

[tomelenbaas]

Thanks to everyone who chimed in on this subject. I'll be implementing some of these suggestions over the weekend to see just what I'm facing.

Tom

[87SunSportMikeyD]

+1 beer for me

[EEES]

How do you pull up the floor? I have like 30 caps on each lateral border of boat. When I remove these caps, I can unscrew all the screws that line the side of the boat, holding the upper wall of fiberglass to the wood floorboards. How can I separate this? Is there a thread? I have an 86 Comp t6m.

Thank you in advance!