Bilge Crack

[SunHarvester]

Looking for input from anyone who has experienced similar issue. Contracting for a well cared for 2014 which has a crack in bilge liner. See attached. This is the aft end of the most aft keel attachment point bilge up where the liner transitions from vertical to horizontal. I am told:
1.  It's not structural part of hull
2.  It's not the result of a grounding
3.  No one can definitively explain how it happened.

Logically it seems for a grounding to have caused this, the hull would have needed to flex to a point that enough strain was presented to this section of the liner to pull it apart?  I'm sure I am oversimplifying this.  And if that were the case,  there would be a lot more other damage showing up on top of this.  The other theory is that this section of the liner was under strain already and that some hard beaters triggered the crack to relieve the strain. The boat was taken apart and no other defects were found.

Any insight would be appreciated. It's a well cared for vessel but I would be a fool to not do some due diligence.

[IslandAlchemy]

That is the main structure of the boat, so it is extremely important.

To me, the most likely cause of a crack there would be a grounding at speed, pushing the back of the keel up into the boat.

The grid system on post 2008 boats is just glued in and not laminated in, so you would be advised to get all of the floor up and look for cracking in the glue where the grid attaches to the hull.  If there is cracking here, it's a major job to fix that requires stripping out the interior, grinding the grid back to the laminate, and re-bonding the structure together with laminate.

It also looks wet and rusty around the keel bolt.  This looks like anything but a well cared-for boat.

If the boat was taken apart and no other defects found, why did they not fix this?

Be very careful.  This smells.

[SunHarvester]

This was just found and is being brought in for repair this weekend.  Apparently it was just recently found, perhaps on a prior survey.  The vessel is otherwise low hour clean as a whistle. 

Seller claims no grounding. 

Caution noted.

Where can I find drawings on the hull structure for the Vision 46?

[IslandAlchemy]

Watch this from 3:35 onwards.  It shows the structure and how it's fitted.

https://www.youtube.com/watch?v=G_VhFSB2b3Q

[symphony2]

Have you (or your surveyor) inspected the external hull/keel joint? As said this looks classic grounding damage - whatever the seller says. The keel is glued as well as bolted on and on grounding the forward part of the keel pulls down and the aft part up so you need to inspect the hull in those areas and for signs that the glued joint, particularly aft of the last keel bolts has not opened up. As you will see from the video the grid is glued inside the hull well up the sides and this needs to be inspected closely as well. It could be that there is no other damage and the moulding was weak in the area of the crack so failed before any further damage.

[SunHarvester]

Just got off the phone with a local naval architect.  I agree with all that much due diligence will be required on this. 

I am also trying to get through to someone at Bavaria. 

Knowing that these are all rigid structures, the remaining gap suggests whatever happened, not everything went back to where it started.  In other words, either the keel is hanging a full quarter of an inch lower aft, or the

I am also wondering if it is at all possible that there may have been a gap between liner and hull at rear of keel that was compressed when keel was torqued. 

Bummer 

[tiger79]

Just walk away; there are loads more boats for sale.  You'll always wonder about the integrity of that boat, no matter what rectification is done.

[Ronald]

Watch this from 3:35 onwards.  It shows the structure and how it's fitted.

https://www.youtube.com/watch?v=G_VhFSB2b3Q

I believe this movie does not show how vision were built as they  have a vacuumed hull, not laid up as in the movie , I am not sure on the frame that may be glued or vacuumed on a Vision.

[SunHarvester]

Haul out and survey (of the crack )revealed no signs of a strike.  Is it possible the keel hit a sea animal, leaving no visible strike location, causing the crack but no other damage?  Not my area of expertise but that seems unlikely.  That would need o be a really big immovable animal.  But I'm open to others thoughts 

Plan is to haul it again, remove entire floor to further investigate before creating a repair plan. 

The angle of the crack where it begins and the wide gap do not add up in my mind. 

Regardless, there is a firm commitment to fix the issue proper, regardless of what that might entail.

Unfortunately,  talk to any broker in the NE and there aren't loads of other boats around.  The inventory for boats is the same as for homes....

So I am going to hang in there assuming this will be made right, and if it isn't, looks like I'll be sitting this season out....

[Markus]

The other theory is that this section of the liner was under strain already and that some hard beaters triggered the crack to relieve the strain. The boat was taken apart and no other defects were found.

Regarding the "hard beat" hypothesis: it can sometimes happen that a section of tabbing between hull and a furniture/bulkhead separates without grounding as that's a secondary bond between fiberglass/fiberglass or fiberglass/wood. But this is something very different as the structural grid has cracked. The grid is likely around 5 mm thick GRP so requires a lot of force to crack.

The general problem with this construction technique (structural liners) is that there is no reliable way to (my knowledge) to inspect if the grid is well bonded to the hull.  And as the vast majority of the hull stiffness comes from the grid, this is extremely important. If there's doubt about the joint as in this case, it can be fixed by cutting out all of the glued sections and tabbing the grid directly to the hull - obviously a huge undertaking!

[IslandAlchemy]

It is possible of course that the boat has been dropped on its keel.

I think the key thing is to look for cracks in the glue joint on the outsides of that keel box structure (not right round the outside, but where the central spine glues down to the hull).

[IslandAlchemy]

Watch this from 3:35 onwards.  It shows the structure and how it's fitted.

https://www.youtube.com/watch?v=G_VhFSB2b3Q

I believe this movie does not show how vision were built as they  have a vacuumed hull, not laid up as in the movie , I am not sure on the frame that may be glued or vacuumed on a Vision.

Not true.  The vision is built in exactly the same way as the cruisers.  Later boats (from about 2018) they started using vacuum resin infusion on all the hulls, but not in 2014.

[JEN-et-ROSS]

Wow..!  That crack looks awful. I've no idea regarding the layup on these particular Bavaria models....But I don't think you need to. ...
You simply walk away..

[Yngmar]

It is possible of course that the boat has been dropped on its keel.

I think the key thing is to look for cracks in the glue joint on the outsides of that keel box structure (not right round the outside, but where the central spine glues down to the hull).

Being dropped on the aft end of the keel seems the best match for this damage. Sling slips happen far more often than yards care to admit and aren't always reported to the owner if they weren't present and the damage isn't immediately apparent

Check if the underside of the keel at the rear end looks flattened (or has been faired).

It also looks like there's a gap between the floor boards and the grid, when they should be resting directly on it?

The grid is hollow and has limber holes - a flexible inspection camera can be inserted into those (or a inspection hole can be drilled if need be). The view from inside will show over what area the grid has cracked from the hull. This is a difficult repair even on a small area, and to repair the grid itself is further involved, as the hull will shift if not properly supported during the job.

[GeoffV]

The problem with this sort of damage is that:
 
1. To thoroughly check/and or repair is very expensive. But for your own peace of mind in the future it has to be done.
 
2. You might think it is ok with a repair but who knows wether it might worsen over time in unseen areas, and you end up with an unsellable boat!

However, as other have said this is a classic walk away. There are enough problems to deal with in the normal course of sailing without this worry.

[SunHarvester]

Well,

As it turns out, I finally talked to the ins surveyor who says that after thinking about it, the owner vaguely remembers possibly hitting something blah blah blah 

I'm going to assume this boat will never be right again.  Kind of like a bent car frame driving down the highway sideways. 

depressing.

All the decent boats don't last but a day if they even make it on a listing.

I think I'll step back and punt on this one.

[tiger79]

I think I'll step back and punt on this one.

Good decision.

[JEN-et-ROSS]

I think I'll step back and punt on this one.

Good decision.

Indeed....

[GeoffV]

Well,

As it turns out, I finally talked to the ins surveyor who says that after thinking about it, the owner vaguely remembers possibly hitting something blah blah blah 

I'm going to assume this boat will never be right again.  Kind of like a bent car frame driving down the highway sideways. 

depressing.


All the decent boats don't last but a day if they even make it on a listing.

I think I'll step back and punt on this one.

A wise man always wins (and saves a big dent in the wallet!)

[JEN-et-ROSS]

 ""the owner vaguely remembers possibly hitting something""
  I'm sure he still remembers the broken ribs he received when he hit the compass binnacle at six knots...!!