Stringer repair under Diesel Engine

[GreenWave]

I am way outside my knowledge zone so wondering if anyone has run into this problem. Looking for advice, experience, line of site to potential repair approach/costs.

During survey found a crack on one of the fiberglass stringers under the engine that runs entire length of engine bay (about 3-4 feet). Engine alignment is also a bit off though shaft is straight. That seems easily fixed but will need to deal with the crack at some point. Good news is that mounts are solid and engine doesn't move during backdown and stress testing. There is an appreciable vibration felt in aft cabin floor behind engine area.

This is on a Catalina 470.
Anyone run into this on ANY boat and what was the approach for repair? Need to get an idea of potential cost and time involved.

Thanks in advance!

Greenwave

[mike d.]

Why don't you contact Catalina tech support ! If split on for to aft length why can't you sister it with G10 if accessible ?! Also more importantly, what would have caused it to do this ??????

[GreenWave]

Originally Posted by mike d.

Why don't you contact Catalina tech support ! If split on for to aft length why can't you sister it with G10 if accessible ?! Also more importantly, what would have caused it to do this ??????

Am seeking multiple sources including what you suggested. Still early in the research and appreciate ah and all input.

[JPA Cate]

Jim had to add a floor and repair two stringers on our previous boat.

There are a number of inconveniences involved with your job. How far forward do you have to remove the engine. Be aware that if you have to scarf in a new timber before fiberglassing over, you need to have 10% of it's length on each end for a good join. So, the engine may have to find a temporary home somewhere outside the boat.

The grinding dust from fiberglass repair will get in everywhere. If you do the work yourself, take all your cushions home. That will leave surfaces you can clean. We also taped up painters' drop cloths. Use the 2" masking tape, you really want the drop cloths to seal off all the rest of the boat. The cleanup is terrible. Wear protective clothing and use a good respirator.

Good luck with it, it was a trying project for us, but Jim got it done, and the leak went away, and the "gronk" rolling downwind also went away. It took a lot of fiberglass and polyester resin, and when finally painted, looked really solid.

Ann

[GreenWave]

Originally Posted by JPA Cate

Jim had to add a floor and repair two stringers on our previous boat.

There are a number of inconveniences involved with your job. How far forward do you have to remove the engine. Be aware that if you have to scarf in a new timber before fiberglassing over, you need to have 10% of it's length on each end for a good join. So, the engine may have to find a temporary home somewhere outside the boat.

The grinding dust from fiberglass repair will get in everywhere. If you do the work yourself, take all your cushions home. That will leave surfaces you can clean. We also taped up painters' drop cloths. Use the 2" masking tape, you really want the drop cloths to seal off all the rest of the boat. The cleanup is terrible. Wear protective clothing and use a good respirator.

Good luck with it, it was a trying project for us, but Jim got it done, and the leak went away, and the "gronk" rolling downwind also went away. It took a lot of fiberglass and polyester resin, and when finally painted, looked really solid.

Ann

Thanks for these details. This is a boat purchase in progress situation so I will either require the current owner to repair or I will seek a price reduction to cover my costs. This isn't a repair job I would do my self personally... it would be subbed out. My gut tells me, based on what I saw, that the engine will have to be removed or at least lifted off the stringers as there is no way to get all the way under the engine to re-glass the entire length of the stringer. again, I am not the expert.

[Fore and Aft]

If the owner gets the repair done make sure he provides photos of the whole repair process. There are a few cowboys around who would do no more than scuff up the gel coat, put a couple of layers of chop strand Matt on the crack, flo coat it and call it fixed.
Cheers

[jimbunyard]

Too much is unknown to give a real even guesstimate.

Could range from zero if the crack is just in the gelcoat, to over 5-6000.00 if the engine has to be removed, a 4' x 4' section of glass and/or timber removed and replaced and made to look llike new again.

[Squanderbucks]

As you stated you are not an experienced fixer for this kind of problem so I would suggest you move on to another boat without these issues and start with learning smaller issues first. Not quite sure how you know the shaft is straight when you can feel a vibration. Was it tested with a micrometer and checkeD for run out.
Engine alignment is not something you can see. It requires measurements within just a few thousands of an inch to be just ok.

[Cadence]

Originally Posted by Squanderbucks

As you stated you are not an experienced fixer for this kind of problem so I would suggest you move on to another boat without these issues and start with learning smaller issues first. Not quite sure how you know the shaft is straight when you can feel a vibration. Was it tested with a micrometer and checkeD for run out.
Engine alignment is not something you can see. It requires measurements within just a few thousands of an inch to be just ok.

Ditto on moving on. What caused the crack would be a major concern for me. Just a cosmetic fix might be what you get?

[GreenWave]

Originally Posted by mike d.

Why don't you contact Catalina tech support ! If split on for to aft length why can't you sister it with G10 if accessible ?! Also more importantly, what would have caused it to do this ??????

Could a lightning strike have caused this? Also learned that the cutlass bearing was replaced and am now wondering if they did a crap job re-aligning the engine (since the engine is out of alignment), thus causing vibration and the crack???

[tkeithlu]

GreenWave, I get the impression that you are looking at a rather badly bent boat. All these "little" problems fit together as the result of a big and bad event sufficient to bend your shaft, dismount your motor, and crack a stringer. Knowledgeable people are asking pointed questions about what happened to do such damage, and are suggesting that getting it right may be a big structural job, not just one crack. You don't have a way of knowing what the total repair will be, because you cannot see the potential damage under things like that crack. This isn't by any chance a U-boat that go too close to a depth charge, is it?

I hope that you will do some comparison shopping.

[Baba Buoy]

Some stringers are hollow. Drill hole on top and fill void space with pieces of teak and fiberglass resin.

[Boatwright]

Aft structural damage is often caused by a hard collision forward. I would approach this boat as a potential buyer very cautiously. A survey is one thing, but often the real story can be found by asking the folks around the marina/boatyard/yacht club..... "Oh you mean Dufos's old boat? You should'a seen it when he hit the breakwater!!"

There are always boats for sale and plenty of "bargains" for the unwary. Unless you are an accomplished high-energy DIY'er think twice, put your wallet away, and look for another boat. The back-ends of boatyards are filled with half-fixed broken dreams, where patience and/or the money ran out before any actual sailing happened.

[ramblinrod]

Originally Posted by GreenWave

I am way outside my knowledge zone so wondering if anyone has run into this problem. Looking for advice, experience, line of site to potential repair approach/costs.

During survey found a crack on one of the fiberglass stringers under the engine that runs entire length of engine bay (about 3-4 feet). Engine alignment is also a bit off though shaft is straight. That seems easily fixed but will need to deal with the crack at some point. Good news is that mounts are solid and engine doesn't move during backdown and stress testing. There is an appreciable vibration felt in aft cabin floor behind engine area.

This is on a Catalina 470.
Anyone run into this on ANY boat and what was the approach for repair? Need to get an idea of potential cost and time involved.


Thanks in advance!

Greenwave

What did the surveyor say about severity?

Could be anything from a cosmetic only crazing to a serious laminate integrity issue.

If no moisture ingress and reasonably accessible repair could be quite simple.

Get a proper evaluation of the issue.

Armchair sailors can offer nothing but amateur speculation.

[Uncle G]

From what I can see online, the Catalina 470 has a fin keel and the engine compartment is at the back end of the keel.


It could well be that the bottom of the keel hit something very solid underwater whilst travelling at speed. That would throw the back end of the keel upwards - which could have moved the engine and broken the stringer. If that has happened, the rig may well have been strained - especially the backstay and its fittings. Also the keel bolts...