Engine stringer structural make up on Ericson 27

Can anyone provide information on what the engine stringers on my Ericson 27 are comprised of? The question is prompted by what is a longish and frustrating story that I'd rather avoid telling. But the short story is I'm contemplating building up the engine stringers (probably with some professional help since I'm not eve sure I'm using the correct terms here), to more confidently secure the engine. The end of my story is that my engine is on shims and the engine has dropped slightly putting things out of alignment, and I want to do this right. Someone asked what was under the stringers (as in what are those lags bolts bolted into) and I couldn't tell him. Thanks. New problem, new saga, new learning experience I guess.

I recently drilled into one of the stringers on my E29, and it appeared to be softwood. Like maybe an ordinary 2x4 under the fiberglass.
About a month ago, there was a thread about stringer repairs. Although I'm not sure if that was in the thread title. Can't immediately find it.

Here's one:
http://www.ericsonyachts.org/infoex...8711-Stripped-holes-in-engine-mount-stringers

toddster said:

thread about stringer repairs

Click to expand...

Not sure if this is the one you were thinking of, but this thread (about converting engine mounts) has some interesting info about the composition of the engine beds (starting on page 2).

http://www.ericsonyachts.org/infoexchange/showthread.php?14647-M25xp-convert-from-3-point-mount-to-4

Thanks for the help. Next question... So, I've consulted with some knowledgeable local marine craftsmen of high repute. The one known for serious structural fiberglass work thinks that while I could build up my stringers that I could keep it simple, make new shims, and lag bolt them in. He thought the mechanic who looked at my engine was not wrong, but was overreacting due to less knowledge about fiberglass etc. So I'm leaning toward the lag bolts and shims. The questions (which are simple, but want to do it right):

How exactly do you fill lag bolt holes with epoxy when the underneath side of the hole is not accessible?
Is the best way with a hardwood dowel, or woodshaving mixture with thickened epoxy? Would that stick in a hole that is open underneath?

Here's are pic of the most problematic mount position (old mount pictured, getting new ones). The sides of my engine bed/stringers on my e27 are not symmetrical. The aft starboard side starts following the hull curve sooner (farther forward than the port side stringer). This mount only had one lag bolt. So i'm thinking of drilling a second hole on an angle as depicted, being careful not to drill into the hull. Although the local expert said I could do that and just glass over it or epoxy it like a blister (not something I'm trying with my skill level).
thanks for any thoughts

I'm looking to work on this today and hoping for some advice. Lag bolts holding in the engine have to be some of the more important connections on the boat and I want to do it right. Thanks. See previous post.

I used a size larger hanger bolt (wood screw threads for stringer, machine screw threads for mount). Slathered the lag end with slightly thickened epoxy and using a double nut tightened them in. They won’t come out again. The only difficulty i had was setting the engine onto the bolts without buggering the threads. In my case the plastic isoflex mounts didn’t cause any trouble when they bashed into the hanger bolts. You could avoid this problem by setting the engine first but then you have to worry about epoxy getting under your mounts and interfering with your ability to align the engine properly. Good luck whichever way you decide.

I have the same problem on my 34-2. One hole on each of the rear mounts are stripped. I had a welding shop weld two nuts on the bottom side of a 1/8" steel plate to accommodate machine bolts to hold the mounts. The steel plates will will be lagged into the stringers with 4 lag bolts each.

I'm moving along with this fix. And have had two local experts who deal with fiberglass repairs and mechanical issues as well tell me that the stringers looks solid. They both said I should save my time, money or both and use shims once my new engine mounts arrive. It was suggested that I could use a material like fir or spruce or oak wrapped with fiberglass matting or coat them with epoxy. But wanted to ask this group, what materials are favored for shims?

Some web searching turned up G10, GPO3, aluminum as most favored. A couple of searches found starboard as acceptable. Thanks for any thoughts on the matter.
jay

I would not use any cast plastic resin product, like 'starboard'.
The G10 product is made from cloth fiber and epoxy and will not crack or break under stress. Note that G10, in thickness over about 3/8", jumps up in price kind of fast. I would suggest a person buy thinner pieces, scuff it, and laminate with some epoxy.

Saved pieces of fiberglass from cutting access holes in the liner? Crazy idea: When I salvaged an old steel greenhouse, I found that the pros who put it up used plastic felling wedges as shims. They held up a whole building roof for 30 years without deforming. Can't remember if I used them when I reassembled it, but what are the odds that that I was so perfect that no shims were needed?

Yep, they're in there. Now that I look at it, they're probably more of a feature than a bug - prevent the gable beams from riding directly on intermediate posts. Anti-squeaking? Hows that for off-topic?

Installed new mounting plates with nuts welded to the underside this weekend along with two new bearers and mounts to replace the single mount in the front.
All mounts are now held in place with machine bolts.

Any change in vibration?

Christian Williams said:

Any change in vibration?

Click to expand...

That's the $50k question. Boat goes in the water in early May. Will do a final alignment after launching and see what happens. Hopefully this project will give new meaning to the phrase "happy motoring".

I can confirm the stringers on my 1977 E27 were just wood with fiberglass over them. When I replaced my A4 with a Perkins M20 I had to raise the engine by about 2" to line up the drive line with the shaft. I just used some Ash beams and coated them with polyurethane for protection. Bedded them with a thin layer of 5200 and used galvanized lag screws to screw them down to the original stringers. Lasted 20+ years without a hitch (or having to realign the engine/shaft).

Kevin Wright
E35 Hydro Therapy

Thanks for sharing Kevin. That looks infinitely simpler than my initial considerations. What I'm going with for now shims only with new mounts. But I like your approach.