Center stringer Pic & question

[Safari]

Hopefully this picture will show up.

If it does, here is my problem. This picture is somewhat confusing due to the perspective. I am trying to show the center stringer that is directly in front of my engine. It was very water logged and rotted. I cut it out to solid wood and now am in somewhat of a quandry as what to do next.

I realize that to do the job correctly the stringer should be replaced, but to do this would require removing the engine. I don't really want to do that.

What do you think of building a "plug" to replace the cut out portion, then sistering & glassing two pieces of 3/4 ply on either side of the plug and tabbing this to the hull with mat and tape?. The combined thickness of the two pieces of ply would equal the original thickness of the stringer. As can be seen in the photo, the lower portion of the stringer next to the bottom of the hull is still in good shape.The sister pieces would extend about two feet on either end of the plug and I think that should provide enough strength to the stringer.

This question is unfortunately the first of a number of stringer questions I will be asking in the future as I have discovered a number of some what difficult problems. You folks have proven in the past however to be very helpfull and I am sure many have better insight than I. Any help would be greatly appreciated.

 

[tashasdaddy]

Re: Center stringer Pic & question

from what is see in other places , i say pull the engine, there's lot of work there to do it right. the next stringer needs to be replaced also, so does the fire extinguisher. get it out before it explodes.

 

[Bob_VT]

Re: Center stringer Pic & question

Honestly... do it right or your might end up doing it twice. None of the wood looks healthy.

Adding a band aid would only be temporary.

 

[studlymandingo]

Re: Center stringer Pic & question

I'd say pull the engine and fire extinguisher. The only way to sister on there is to get on good wood all the way back which would also require the removal of the engine.

 

[dmarkvid2]

Re: Center stringer Pic & question

Yup, do it ,,,do it right. It will definatly come back and huant you. What is that tube that runs up near the extinguisher?

 

[B.M.W II]

Re: Center stringer Pic & question

From what i see none of the stringers look good. If you are going to keep this boat and use it often I would do the whole floor. But if you are not going to keep it and dont want to spend alot of money in it. Then your idea would do for a temporary fix. And please take (tashasdaddys) advice and get that rust fire extinguisher replaced ASAP.Before that thing explodes and you have a hole in the floor and side of the boat.

 

[calwldlif]

Re: Center stringer Pic & question

I put sistered 2X4's across my gunnels
to hold the engine while I changed out the stringers.
I got it done but it would have been easier to have
the engine out of the way.
My gunnels were beefy enough to hold the engine weight

 

[Safari]

Re: Center stringer Pic & question

Thanks for the input, the extinguisher is history. I didn't knom they could explode

 

[fishingdan]

Re: Center stringer Pic & question

If you are going to just slap it back together, you can put a patch in there and bond it to everything in the area with epoxy and structural fiberglass (like a 12 oz biaxial). However, I agree with the others. If you plan to keep the boat, do it right and gut it.

 

[tashasdaddy]

Re: Center stringer Pic & question

if you don't plan to keep it. bite the bullet and sell it as is, rather than screw some rookie boater.

 

[sundog]

Re: Center stringer Pic & question

like the others, replacing is the best option. Your idea is a good one, though, and would work fine for a while. Ive seen this done in the islands with older boats (and lazy islanders). Instead of cutting the stringers out, they would sandwich the stringers with marine ply the whole length of the stringer, thru bolt them, then either glass over everything or leave it as is.

It actually would make for a very strong stinger for the next few years, but the weakness was the stinger/hull fiberbond, and not addressing the rot in the original stringer. After a few years, your going to have to do it the right way.

also, tash is right...if you sell it, make sure to tell the guy you sell it to its jury rigged and needs to be addressed. Cant tell you how many guys 'forget' to mention rotten stringers/transom.

 

[Safari]

Re: Center stringer Pic & question

Hi,
Got back to the puter after a few days of working on the boat and saw the responses. I like the boat and do not plan on selling it.

I have been pulling out the bad ribs and exposing more of my inside center stringer for replacement. I will post more pics later. I think the rot was caused by leaking windows and deck hardware/fittings. The water must have run down the interior sides of the hull and accumulated on the underside of the flooring under the dinette/seat unit. It would have not been visible from top-side. Eventually it rotted away the top of the stringer. The stringer was tabbed with resin and mat to the hull. This tab runs the full length of the stringer, extending upwards about 4" up the side. The wood in this area is solid, so I have been cutting out the bad. I will post pics to clarify this situation later.

Thanks

 

[Safari]

Re: Center stringer Pic & question (Update Pic)

Re: Center stringer Pic & question (Update Pic)

This is what I was referring to.

The photo is a very low shot showing the underside of the dinette. I have removed the ribs and they will be replaced. In order to completely replace this stringer I would have to gut the boat. This would be a huge undertaking. That is why I have been leaning toward the sistering idea.

 

[Solittle]

Re: Center stringer Pic & question

Have you checked the transom? Often if you have stringer rot the transom will be gone as well.

 

[Safari]

Re: Center stringer Pic & question

Solittle,

The transome is solid. No water got to it. There was a bulkhead (below the engine) about 4 feet in front of the transom to which the stringer was attached. The large motor mount stingers (pictured) transferred the support to the transom.

Those are the two templates I am contemplating using, dry fitted in place.

 

[Mark42]

Re: Center stringer Pic & question

After much "analysis" of the photos you provided, I conclude the following:

If you're comfortable with it, I'm comfortable with it. 8)

It looks like you have a good handle on the actual condition of all parts involved, so if all the damaged material was removed to clean solid wood, then I don't see why a quality patch will not last the life of the boat.

Some of my thoughts are:

- Definitely a job for epoxy, not poly resin.
- Make sure you have as much contact as possable between the remaining stringer under the front of the motor area with the plywood supports.
- Consider through-bolting with 2 3/8" stainless steel bolts and washers in that area, but not so tight as to squeeze out all the epoxy. Looks like it would be hard to fit a drill in there, though.
- Make sure the old wood is treated with a product that will stop/kill the rot in case there are still some active microbes left behind.
- Make sure some "pie" shapped supports go back under the dinette floor. Epoxy in place and attach well to new stringer support.
- Make sure everything is DRY before assembly. Can test with a 1/8" drill bit. Drill into questionable area and inspect the shavings.

New stringer would be preferrable, but I don't see why a well designed repair will not yield the same end result: A solid stringer and well supported hull that will last. It might be heavier than the original, but that is a trade off to the time and material savings.

 

[Safari]

Re: Center stringer Pic & question

Mark42,

Thanks for your insight. The suggestions are very helpfull and I shall follow your lead. Even though the floor will be done with poly, the stringer will be with epoxy! You are correct that I can see the extent of the damage better than the pictures can depict that is why I am continuing in this direction. Slowly but surely the parts are getting cut and dry fitted into position. If, for some reason, things do not go according to plan I may have to change my mind and gut the boat

It has been very depressing seeing all of the rot caused by leaking windows and poorly sealed hull/deck fittings. l'm sure many folks here have had the same feelings as they began their projects. Each day however gets closer to the end. No matter how daunting the chore seems at first there is light at the end of the tunnel. It's like that age old question how do you eat an elephant...one bite at a time. Thanks for the support

 

[Mark42]

Re: Center stringer Pic & question

Hey Safari!

What's the latest with the fix? Got some pics?

 

[MercMark]

Re: Center stringer Pic & question

I would agree with the opinion that the fix may work well enough.

I would add that:
-you should not count on the old stringer or filler block for any structural thickness. All of your strength will be coming from the new wood. You are right to try and add up the new wood to the thickness of the original piece. There should be no problem with them being spaced apart (if you will indulge me to make a real stretch of an analogy) in housing you can space the two plies of a lintel and it's still considered to have the same strength provided it's blocked and fastened correctly.

The only other concern I would have is where to end the new patch pieces. Ideally they would be the same lenght as the original piece, and not end only a foot or so past the patched area.

Ok so I have one more concern and it's echoing the idea that you need to find a way to dry it and kill any little life forms that may be living in there.

 

[MercMark]

Re: Center stringer Pic & question

Oh and I would also like to ask:

Is the space under your galley floor connected to the bilge? this would be normal wouldn't it? That way if any water gets in the cabin it can drain back to where it will get pumped out with the rest of the bilge water.

If that is the case, the bilge is likely the source of your moisture as well as the leaking windows.

I haven't seen the bilge arrangement in too many cabin cruisers though. Only my dad's Chris Craft Connie which is wood and a couple of dorals from the 90s