1985 Beneteau 37 First Hull weakness????

[ManiacHunter]

I am ready to sea trial a immaculate 37 First 1985. Looks like a time capsule inside out. Bells and whistles. The broker, who I consider a friend, has let me know and offered full documentation by Beneteau company reps who saw it, that when the boat was on the hard for bottom painting, forward of amidships starboard was a slight impression of the pad of the hull that straighened out when the boat was back in the water.

The area effeced was about a foot long as an elipse and at the time any repair would have cost about 900 dollars to cut it out etc. Money was not an object at the time of the bottom job and so it was not done. And the beneteau rep sent out to review it at the owners expense said that it was not a problem - whatever that means

Has anyone heard of this deformation . The liner inside apparently did not allow them to see if there were any structural problems such as a missing strengthening member

John

 

[Prime Time]

Hull Deformity

I'd make sure that there is no hull delamination or a wet core.

That being said, many boats are engineered to be only "just strong enough" and have relatively weak hulls compared to stronger layups of other boats. They may have a system with reinforcing load bearing stringers that distribute loads over broad areas, but when you point load them, they can deform. With some boats, its very important that the jack stands be placed in a location that is reinforced by a transverse bulkhead.

There was a very successful light weight one-off at our club that when on its trailer had massive deflection where the pads were. It lasted like this for yrs, but was only used around the buoys. She was eventually cut up and scrapped.

When I was doing the inspection on my Bristol, she was short hauled for the survey. The travel lift operator accidentally put her down on a Jack Stand that was in the wrong position. The Jack stand was broken like a twig. No hull damage or even a craze to the gelcoat. My old Mirage would not have faired well.

 

[ManiacHunter]

Thank you - anyone elses experience would be appreciated also.

 

[SycloneDriver]

I now this example is of much small boats but... My 1979 San Juan 23 and 1979 San Juan 7.7m deformed badly when not suported correctly on the trailer, but when put back in the water they were/are fine. I have added more jack pads to the trailer and the SJ7.7 looks fine as of today, its been out of the water for about 3 weeks now.

I wonder if you could inject some expanding foam between the liner and the hull to add some stregth. They use foam in car chasis to add stiffness. It must be the correct type of foam.

 

[ManiacHunter]

Thank you for the jacks advice and foam - I will look into that. John

 

[Jackdaw]

Beneteau uses an internal structural 'grid' pan that is secured via industral adhesive to the hull. It is what gives the boat it's strength. The lift points and cradle pad points are aligned to this grid for maximum strength. It sounds like the boat was placed on a cradle way off of these points and the unsupported hull flexed in. I'd also guess that the yard screwed up and did not have enough weight on the keel. The flexing glass is probably ok if it did not delaminate. Also important to make sure the the hull did not break away from the grid near the spot of the deformation. If the grid looks ok (may be hard to get at, depending) then I'm guessing you are ok. Have someone you trust look at it of you are not sure..

PS - the hull is solid, not cored. No worries there.

 

[ManiacHunter]

thank you!

 

[Ray Bowles]

Most trailered boats that are on roller trailers show defomation around the contact site. My San Juan 23 and 2 others where I sail show such markings. They go away in the water. It has never been a problem in the last 29 years so we don't worry any more.
Ray

 

[Big Windy]

Most trailered boats that are on roller trailers show defomation around the contact site.

I've seen this in my marina. Sometimes it happens because the owners leave the tie downs tight with full tension on the boat when it is sitting on it's trailer. If they are loosened when not being moved, it's better for the hull and the deformation is less likely to happen.