About a hull that has been deformed by a jackstand

[Ceto]

There's an area on the hull of my boat where there is a bit too much pressure. The hull has been pushed in a little bit by the pad of the jackstand. There are no stress cracks.

I was wondering if the hull will return to normal when the pressure from the pad is removed...

[Summersdawn]

I had a similar probelm with a jackstand on my boat. Once pressure was off, it went back to its original shape. I wouldn't leave it too long however, as fiberglass will deform over time.

[The Froon]

Ceto:

Did your hull ever return to shape?

If it had not, what would have been the process to correct?

Thanks,

Brian

[Idon84]

I'm not an expert here FOR SURE but I think if my hull was deformed from a jack-stand (better go adjust mine now) I would try to reshape the area by applying pressure from the convex side of the dent and then build a sturdy hat shaped stiffener to correct? Of course you need to have access from the inside.

Have a Thistle whose previous owner built the trailer's forward bunk about 1' further forward than it should have been. The bunk didn't deform the hull but instead made it weak from the bouncing on the trailer. Every time I hit someone's wake I got a dull, echoing, drum tone from the bow. I rebuilt the bunk in the correct place and put hat shaped stiffeners in to correct the problem.

Got some pictures of the process on my picture site under "Thistle Rebuild"

(NOTE: Looking at the pictures now, the stiffeners are NOT carefully built as they should have been. There is no taper to the stiffener for the cloth gently curve only a 90 degree bend. Learned this after the fact. Oh well works great for now!)

[Ceto]

Ceto:

Did your hull ever return to shape?

If it had not, what would have been the process to correct?

Thanks,

Brian

The thing is, the boat is still on jackstands and it will stay there for several months...

So I don't know how things will turn out...

[bcooke]

'Normally', the boat should not be supported by the jack stands. That is what the keel blocking is for. The weight of the boat should be resting on the blocking. The jack stands just stabilize the boat and keep it from tipping over. Under 'normal' circumstances you should be able to back off the pressure on the jack stands.

Maybe you should ask the boatyard about it.

[David VanDenburgh]

I agree with Britton about talking to the yard.

After buying my Alberg 30, I noticed that one of the poppets on the cradle was deforming the hull. The yard was very accommodating and readjusted the boat. I was a new owner and yet the yard still worked with me - for free. Good people. Perhaps your yard will be equally cooperative.

If they agree to move the stand, ask if they can place it on a bulkhead.

David

[Ceto]

It's not placed in a boat yard. I'm on my own...

[Tim]

Simply move the stand to another location, and adjust the tightness of all the stands so they're tight (i.e. not sloppy), but not too tight. Putting stands in way of bulkheads is a good idea if you can; the hull is far stiffer here.

Depending on how long the hull has been deformed, the area will either regain its shape immediately, within a day or two, or not at all (rarely).

If you're not familiar or comfortable with moving stands on your own, then purchasing or borrowing one extra stand may make this process easier and safer. Use the spare to support the hull while you move the other stand, or place the "spare" in the new location and remove the old, creating a new spare.

Also, check your keel blocking. Often, these will shift or sink partially into the ground, increasing pressure on the jackstands. Stands always need regular inspection and adjustment to account for natural changes in the way the ground is supporting the boat.

Boats have been being deformed by improper blocking and stand placement forever. Don't sweat it, but do take steps to correct it now.

[John, CD28]

I keep my boat on dirt out behind my house. The dirt under the keel blocks will settle a bit at first before it firms up. The keel blocks on my boat settled into the ground the first few weeks I put here there, pushing a stand up into the hull. I just backed the stand out, and the dent came out of the hull as I backed the screw out. I went around and took some pressure off each of the stands, and all was fine. Again, only the keel blocks should carry any boat weight; the stands just keep here balanced on the keel. I later sounded the area of the dent with a 2oz mallet, and it seemed fine. No delamination, no cracks.

I know of a guy who looked at a Cape Dory for sale that had settled onto her stands and was never adjusted. The boat sat like that for years. The stands left four large dents in the hull that didn't back out with the screws. The dents appeared permanent and the buyer used this fact to negotiate the price down, thinking a very expensive repair was in order. He bought the boat, and just put her in the water. When he hauled several months later, the dents were gone!

When setting a boat on dirt, be sure to use keel blocks with a lot of surface area to minimize settling. I use long 6x8s with 2x10s spiked on the bottom for snow shoe effect. Use three stands per side with chain, and check & loosen the stands if needed every few days when the boat is first placed. With six stands, backing one off at a time is no problem. Once the dirt under the blocks compresses and stabilizes, she'll be fine if you have a good long keel.

Best,
John