Deck stress cracks underneath upper, and forward lower

[Alan Gomes]

I just recently noticed these stress cracks underneath the U-bolts for the upper and forward lower shrouds. This is on the port side. There is an aluminum block underneath the deck, through which the U-bolts are bolted. Then, there is an adjustable tie rod that runs from the aluminum block to a heavily glassed-in attachment point lower on the hull.

In 2013, shortly after I purchased the boat, I had all of the chain plates removed for inspection, including the U-bolts, the aluminum block, and the tie rod. The U-bolts were suspect, so I had new ones custom fabricated by Garhauer. The aluminum block and tie rod were just fine. I also changed out all of the rigging.

It seems to me that there is a bit of a depression where the U-bolts penetrate the deck. This makes me wonder whether the rigger may have gotten a bit too enthusiastic when he tensioned the tie rod. But these cracks were a long time in coming. At any rate, as far as I can see, the deck would not take any of the shroud loads but the tie rod and lower hull attachment would--assuming the rod is tensioned properly. FWIW, I have not observed any change in the shroud tensions over the years, so that is holding well.

The starboard side does not show these cracks. That attachment is via a conventional chain plate bolted through a wooden bulkhead.

Have any of you seen cracks like this in connection with your shrouds supported by tie rods? Have you adjusted the tension on the tie rod? How do you know how to effect a proper adjustment? Any other thoughts on this?

 

[Prairie Schooner]

Likely you attended to both these, but: Do you know if those holes got the epoxy/redrill treatment? Rod/MaineSail is pretty adamant about chamfering any holes in gelcoat, too.

 

[Alan Gomes]

Likely you attended to both these, but: Do you know if those holes got the epoxy/redrill treatment? Rod/MaineSail is pretty adamant about chamfering any holes in gelcoat, too.

I did not do the epoxy/redrill treatment. But I did chamfer the holes before adding sealant.

 

[Loren Beach]

Some years ago a friend with an E-33RH had the standing rig inspected. The rigger noticed that the deck surface was slightly lifted on each side at the shroud attachment points, and he turned the Navtec rod inside while having a helper sight up the deck surface and tell when it was properly flat. Evidently a prior owner had not done this work.

 

[Alan Gomes]

Some years ago a friend with an E-33RH had the standing rig inspected. The rigger noticed that the deck surface was slightly lifted on each side at the shroud attachment points, and he turned the Navtec rod inside while having a helper sight up the deck surface and tell when it was properly flat. Evidently a prior owner had not done this work.

Interesting. I think in my case it might be the opposite: I'm wondering whether the rigger was too aggressive with tightening the Navtec rod.

 

[dcoyle]

Included with the original owners info for my 82 E33 is some info on the connecting rods. When boat is out of water with rig not installed, they should be hand tightened. Once in the water a 360 degree turn to tighten.

 

[Kenneth K]

Gelcoat cracks aren't always stress related but the 360 degree encircling of the chainlplates does make this look suspect.

If you pour water over it, does that area form a "bowl, i.e., is it a depression inside the cracked area?

Can you get a look at the underside through the headliner? When I removed my winches, I could see physically depressed areas under the washers. The wood/frp sandwich will deform & compress over time when subjected to stress. The gelcoat just cracks.

 

[Alan Gomes]

Included with the original owners info for my 82 E33 is some info on the connecting rods. When boat is out of water with rig not installed, they should be hand tightened. Once in the water a 360 degree turn to tighten.

This is interesting. Thanks.

 

[Alan Gomes]

Gelcoat cracks aren't always stress related but the 360 degree encircling of the chainlplates does make this look suspect.

If you pour water over it, does that area form a "bowl, i.e., is it a depression inside the cracked area?

Can you get a look at the underside through the headliner? When I removed my winches, I could see physically depressed areas under the washers. The wood/frp sandwich will deform & compress over time when subjected to stress. The gelcoat just cracks.

Good questions, Ken.

I was very busy finishing up some items related to an engine swap my friends and I did a bit over a week ago when I noticed this, so I was not able to give it a good inspection. I did run my fingers over it and it appears to be somewhat dished downwards. I need to put a straight edge on it, and also compare it to the starboard side. Pouring some liquid on it is also a good idea, so I'll do that too.

Yes, I can get a look under the headliner. It's a bit tight under there, but using a mirror I should be able to see it OK. If it is a matter of the tie rod being overly tight, as I suspect, there probably will not be much to see from underneath. But I definitely need to look at it.

 

[bigd14]

The wood/frp sandwich will deform & compress over time when subjected to stress.

On my 30+ of the same era I believe the area around the chainplates does not contain wood core. At least I remember being pleasantly surprised not seeing any when I replaced the ubolts. You should probably check anyway.

 

[Pete the Cat]

Interesting. I think in my case it might be the opposite: I'm wondering whether the rigger was too aggressive with tightening the Navtec rod.

I agree. There are some things I think are better left alone if there is no obvious indication of failure. Chainplate removal is one of them in my book. I replaced all my rigging on my Tartan 37 before a two year cruise of both coasts of Central America and this was the only time I had rigging failure in my 50 years of sailing--the new forward lower swage fitting simply let go in modest seas a couple months into the trip. The Ericson TAFG seems quite bulletproof and obvious in terms of being able to see incipient failure. Other boats with hidden buried chainplates might have more reason to be removed for inspection. I doubt if this is anything but esthetic damage, though it might have created an opportunity for water ingress.

 

[Loren Beach]

On my 30+ of the same era I believe the area around the chainplates does not contain wood core. At least I remember being pleasantly surprised not seeing any when I replaced the ubolts. You should probably check anyway.

One bit of trivia, and it might apply more to late-80's EY built boats --- And, our SS shroud bases now are epoxy-potted-redrilled and sealed, after our recent re-fit.
Our deck did have balsa coring visible where the large bolts penetrated the deck, on their way to the aluminum block inside that houses the Navtec headed rod. We had experienced zero water leakage and the coring was dry. I have some pix of these shroud fittings in my blog here. https://ericsonyachts.org/ie/ubs/gear-removal-progress.786/

Worth noting tho is that I also re-bedded those shroud base deck fittings back in '04, when the spar was down for a new standing rig. This time we carefully observed the deck layup in that area. The layup was noticeably thicker/heavier there. I would estimate that the heavier layup was at least a foot wide, and spanned the deck from rail to cabin side. This seems to be in keeping with the thicker layup we observed in the center part of the transom where the backstay tang is thru bolted.
EY did not seem inclined to foolishly save a buck anywhere that the structure needed to be more rigid for higher loads.

 

[Alan Gomes]

I agree. There are some things I think are better left alone if there is no obvious indication of failure. Chainplate removal is one of them in my book. I replaced all my rigging on my Tartan 37 before a two year cruise of both coasts of Central America and this was the only time I had rigging failure in my 50 years of sailing--the new forward lower swage fitting simply let go in modest seas a couple months into the trip. The Ericson TAFG seems quite bulletproof and obvious in terms of being able to see incipient failure. Other boats with hidden buried chainplates might have more reason to be removed for inspection. I doubt if this is anything but esthetic damage, though it might have created an opportunity for water ingress.

Thanks for your thoughts on this, Pete.

In my case, it's a good thing that I pulled those chainplate U-bolts. A few of them had visible cracking, so I replaced them all with new, even more robust ones made by Garhauer. So overall I'm glad I did the inspection on all of these items.

That said, I'm hopeful that this may be only a cosmetic issue, as you suggest, but only a careful inspection will reveal that. I need to confirm that there is indeed a depression in the area, which will be easy enough to do next time I'm down at the boat and not rushed to button up the boat and head home. I also need to confirm whether there is wood core in the area and, if so, its condition. I'm probably due to rebed these U-bolts anyway.

 

[mjsouleman]

Shrouds are a project I put on my to do list last year when during g a rain storm while I was reading on the port side I had water dripping on my head. Upon opening the over head zipper, I noticed the shroud under base was wet with droplets.

The plan is to drop the mast, and cut the deck open from the under side to remove wet core. Then add thee layers of cloth to the under side of the deck, add new foam core, replace the cut away underside that was removed earlier, and replace the aluminum block with 6 inch Gten fiber glass backing blocks.

Oh, and user drill shroud holes and fill with epoxy.

Mark "souleman" Soule

 

[Guy Stevens]

Looks like the Rod is over tightened. Causing the deck to be collapsed under the mounting plates.
Needs to be removed and evaluated. Possible solution may need to include repairing the top skin if the cracks are more than gell coat deep.
If there is core in this area ( I believe there is) it should be removed and filled with epoxy once tge skin is repaired.
There is a depression visible in the photos. This is a common problem when people decide rigging is meant to be as tight as possible.

:-(

 

[Alan Gomes]

Looks like the Rod is over tightened. Causing the deck to be collapsed under the mounting plates.
Needs to be removed and evaluated. Possible solution may need to include repairing the top skin if the cracks are more than gell coat deep.
If there is core in this area ( I believe there is) it should be removed and filled with epoxy once tge skin is repaired.
There is a depression visible in the photos. This is a common problem when people decide rigging is meant to be as tight as possible.

:-(

Thanks for your input, Guy! Much appreciated.

 

[Alan Gomes]

Looks like the Rod is over tightened. Causing the deck to be collapsed under the mounting plates.
Needs to be removed and evaluated. Possible solution may need to include repairing the top skin if the cracks are more than gell coat deep.
If there is core in this area ( I believe there is) it should be removed and filled with epoxy once tge skin is repaired.
There is a depression visible in the photos. This is a common problem when people decide rigging is meant to be as tight as possible.

:-(

Follow up question: How does one determine how tight to tighten the rod? It's a bit different from tensioning wire rope, where you can roughly judge its tension by pulling on it, or by using a Loos gauge.

 

[Frank Langer]

Follow up question: How does one determine how tight to tighten the rod? It's a bit different from tensioning wire rope, where you can roughly judge its tension by pulling on it, or by using a Loos gauge.

The ericson manuals suggest that when the rigging is loose, the tie rod should be hand tight, then one more full 360 degree turn. Then tune the standing rig as usual.
Frank

 

[Alan Gomes]

The ericson manuals suggest that when the rigging is loose, the tie rod should be hand tight, then one more full 360 degree turn. Then tune the standing rig as usual.
Frank

Thanks

 

[bigd14]

The plan is to drop the mast, and cut the deck open from the under side to remove wet core. Then add thee layers of cloth to the under side of the deck, add new foam core, replace the cut away underside that was removed earlier, and replace the aluminum block with 6 inch Gten fiber glass backing blocks.

Oh, and user drill shroud holes and fill with epoxy.

Mark can you see the extent of the wet core from under the side deck? Hopefully it’s a limited area. It might be easier to just add a square of 1/2” G10 to the shroud area in place of the foam core material. No compression or leaking into the core worries then. Good luck with the project.

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