Sagged Hull

[Le Bon Reve]

We have our CS 36 Merlin in San Carlos MX. We left it here in June for a bottom job. It was hauled to back of yard which is sandy for the dirty work.When we arrived back in october they still had the boat sitting in the bak[sand]. When I looked at it ,it looked skewed. when I went aboard the floor boards were askewed & would not fit. Ill supported at the rear end for sure & we are rear heavy with radar arch hydrovane,solar etc.. We had the boat moved the other day & it is on concrete now. It is toally obvious that the rear 1/3 of the boat has dropped. When I put a straight edge on my floor boards where the sag starts the drop is over 1" in a 4' run. It sagged from the stringer that is even with the center line of sink doors. Wondering if there are any Merlin owners who can tell me if they have any drop in that span. Also would love to hear about the compromising to the strenght/performance of boat from someone with knowledge. The interior has a liner above the bilge so it is hard to see if the interior of the hull has cracked at all. where I can see up the sides of the hull I notice nothing
Thank You

[onestepcsy37]

If you run a chalk line along the deck is it level? Should it be level?

[ssanzone]

I cant speak to any specifics of Merlins...

Are you suggesting that the boat stands being set in sand resulted the sagging?

While I can see how that might happen, those dots are pretty far apart and difficult to connect. I can conceive of this happening if you had a flat spot / indent in the hull from the stands slipping and 'too much' weight was resting on a single stand which was on / near a stringer... if the stringer moves the everything attached to that stringer will also move but that would, I think, result a shift port to starboard not fore to aft.

Do you have pictures (ideally before and after)?

Sorry I cant directly answer your question.

-steve

[CptLawrence]

Try wrapping a hammer in a rag and tapping the hull from keel to rails, end to end. If something has become detached or cracked or delaminated you will hear a difference and know where to check further.

[misfits]

I'm no expert but I've seen several posts from folks that have said their boats were tweaked due to being on the hard. Once back in the water & the hull is uniformly supported, things return to normal.

[ssanzone]

Originally Posted by misfits

I'm no expert but I've seen several posts from folks that have said their boats were tweaked due to being on the hard. Once back in the water & the hull is uniformly supported, things return to normal.

But an inch over 4 feet?

If a stringer did separate from the hull it will certainly close to its original state but I would not want to be getting knocked around in high winds without stringer attachments.

Eep... scary!

-steve

[neilpride]

Jackstands need a plywood pad under the legs to avoid severe sinking in the ground and they need to be under bulkheads or solid stringers to avoid oilcanning if the boat sink in the ground, normally everything back to normal after reposition Jack stands, check your hull liner inside if you can for cracks under the joints with the hull, obviously pictures will be great....

[roverhi]

A boat should sit on it's keel with no other support except to keep it from tipping over. The usual problem is the keel sinking into unstable ground faster than the jack stands. That can result in 'dimples' in the hull where the stands push the hull in as they take to much of the load. The 'Dimples' can be permanent though not structurally an issue unless they are under a structural internal member. Never heard of an FRP boat sagging like your boat has. Might check to be sure that it really has sagged. Hopefully a CS owner will chime in with their experience.

[motion30]

Originally Posted by misfits

I'm no expert but I've seen several posts from folks that have said their boats were tweaked due to being on the hard. Once back in the water & the hull is uniformly supported, things return to normal.

What he said. don't panic until you put the boat back in the water

[lesterbutch]

Originally Posted by motion30

What he said. don't panic until you put the boat back in the water

Being a former boat builder I would say you should have a structural survey done. Any time a stringer is affected as you say one was, you need a professional survey. Keep in mind structural integrity is what keeps you alive at sea.


Sent from my iPad using Cruisers Sailing Forum

[barnakiel]

IMHO the hull should not visibly change its shape while on dry for indefinite time.

I would consider a very very thorough attitude to this challenge.

You can make reference points then measure again when she is in the water. If there is a major difference / movement, have the boat surveyed (unless you are not doing any extensive / exposed sailing).

Step lightly.

b.

[zeehag]

check interior bulkheads carefully for separation from hull/deck.
check everything for intactness.
personally,. i would pay for kjels christian to come down from san diego and inspect it closely. he is an honest and awesomely intelligent surveyor. SAMS certified.
tell him the lady who went around on surveys with him sent ye.
have kjels make out a list of actual damages resulting from improper blocking of boat, and go from there.
are you in the singular yard???