Serious Catalina 30 Oil Canning on Factory Cradle

[Project_Mayhem]

I discovered a buckled crack in the floor liner of my 94 C30 next to the nav station. Upon further investigation I found broken tabbing under the forward section of the after berth, more cracks in the liner in the same general area and some serious oil canning on the starboard aft cradle pad. I believe this is the original C30 cradle. I see a small amount of oil canning on the port side pad as well. I initially suspected that the keel didn't have enough blocking on the aft side.

I talked to the yard and they stated that it's not uncommon to see this with the Catalinas. He said that the factory cradles are too short (not sure how a longer one with the same number of pads would help) and that next year I should request stands instead. There's literally no bracing or a bulkhead where the pad touches. Just a little bit of tabbing to the floor liner. The yard said they would add four stands to the stern, pull the pin on the cradle pad and let the hull relax for a while. Their interim solution seems reasonable but I still suspect that the blocking could have been better.

Oil canning looks worse in person than in the photos. Does anyone have any thoughts on the current situation and future prevention?

 

[jssailem]

First, as a new to you boat owner of a mature boat, I have been there and have winced at the discovery of similar issues. For some boats it is the way they have been sailed hard in heavy weather that the conditions found the weak points of a boat build and exposed them. In your neck of the woods, the boats are exposed to stresses that were not anticipated in design when they are removed and stored on the hard each year for the past 30 years.

I do not believe these discoveries will sink your boat.

It is wise to address the cosmetic and underlying tab structures to provide your boat with its best long life. It is wise to identify where the boat strong structure is and place your pads/supports there, rather then between the strong points, while on the hard.

Of note, your boat design utilizes the thinking of the time. To build a fast boat you need a light boat. The Catalina design applies this thinking to the boat build by utilizing an interior pan structure (the framing of the boat) on a thinner hull than other boat builders. Where you find failed/failing tab attachments, repairing the tabbing pan/hull connection will strengthen your boat.

If you were considering crossing the Atlantic then adding braces between the tab points might be beneficial. If you plan to race your new to you boat and will be exposed to the worst conditions the Great Lakes can conjure, then exploring additional interior bracing to help maintain the hull form would be a worthwhile effort.

If these extreme sailing plans are not in your future, then doing the cosmetic repairs, reattachment of loose tabbing, and care in how the boat is stored during winter will give you many pleasurable sailing seasons.

You made a wise choice. I hope you enjoy the 2025 season on the water.

 

[Project_Mayhem]

I agree that this isn't detrimental to the boat's structure or the 2025 sailing season. I believe the fiberglass work is best done on the water after the hull has had a chance to relax. Thankfully the tabbing is fast and easy. I'll have to learn to match gelcoat for the cosmetics but that's a topic for another thread.

The interior pan, in my opinion, is not up to the task at hand. There's clearly a few thousand pounds of weight on that pad. Either some heavier reinforcement or bracing is needed or the boat needs to be stored differently in the future. The question become which method(s) and how to go about it/them

 

[KCofKC]

Not seeing the cradle I can't address this but to me it seems there is not enough weight on the keel, the bunks or pads are to supply some support but mostly stability.

 

[john2]

I agree, small pads can not take load / weight . Just for stability. Best to make custom pads which are in the shape of the hull.
And bigger is better! Spread the force over the hull.

 

[KCofKC]

In the first post the first photo shows the cradle up on blocks, perhaps the keel was unsupported which I suspect it has expedience some where along it's journey. This in my view is not a Catalina issue but a yard issue. I also do not believe there is enough pad support. There is noting supporting the back 1/2 of the boat at all, two stands here would help immensely.

 

[Ward H]

My 93 C30 does not show the same oil canning nor the cracks in the gel coat or tabbing.
For the 7 years I've owned the boat it has sat on four pad cradles.
I agree with the others that most likely that corner pad was jacked up too tight putting too much pressure on the hull and or the keel was not properly supported.
I also agree with your plan to let the boat settle once it's back into the water before making the repairs.

 

[Project_Mayhem]

My 93 C30 does not show the same oil canning nor the cracks in the gel coat or tabbing.
For the 7 years I've owned the boat it has sat on four pad cradles.
I agree with the others that most likely that corner pad was jacked up too tight putting too much pressure on the hull and or the keel was not properly supported.
I also agree with your plan to let the boat settle once it's back into the water before making the repairs.

There adjustments on the cradle pads aren't very fine. The holes for the pins are about 2" apart. I might add some additional holes so the yard can fine tune it. I still think that there's too much weight on the rear. Perhaps the back of the keel should have more blocking to raise it up a bit

Do you know if the hull and liner are the same on the MK2 and MK3?

 

[jssailem]

Perhaps the back of the keel should have more blocking to raise it up a bit

Sounds like a reasonable action. The keel is intended to support the boat's weight. The blocking is designed to stabilize the boat.

 

[Ward H]

Do you know if the hull and liner are the same on the MK2 and MK3?

If your C30 has the sugar scoop transom the aft part of the hull is more rounded and the cockpit is wider than a Mk2. Not a stretch to think the floor pan and hull in the area of your issue is different. If you don't have the sugar scoop transom, then they would be the same. Mk2s can have many the small features of the Mk3s, mine does, but the change in the hull and cockpit designate the Mk3

The cradles I've been put on have screw jacks to fine tune the adjustment of the pads. I know the boat is lowered onto a support beam that runs full length of the wing keel. Then the pads are bought up to the hull. The beam supporting the keel is part of the cradle structure so uneven ground will not allow the keel to "sink", putting more weight on the pads over time.

In your case I would expect the keel should be supported to a height so there is minimal weight on the pads.

Perhaps the back of the keel should have more blocking to raise it up a bit

I think you got it. And use various thickness's of plywood at the pads so they are snug to the hull but not taking load.

Is that a wooden "box" raising the cradle off the ground? If it is, I wouldn't trust it. Looks like it could very easily collapse sideways.
Probably should be solid wood stacked for the hight. Our marina has bins of 6x6"s or 8x8"s for the purpose.
Is the cradle raised to make room under it for the keel? IE: Does the keel extend below the cradle? If so, that is scary.

 

[Project_Mayhem]

If your C30 has the sugar scoop transom the aft part of the hull is more rounded and the cockpit is wider than a Mk2. Not a stretch to think the floor pan and hull in the area of your issue is different. If you don't have the sugar scoop transom, then they would be the same. Mk2s can have many the small features of the Mk3s, mine does, but the change in the hull and cockpit designate the Mk3

The cradles I've been put on have screw jacks to fine tune the adjustment of the pads. I know the boat is lowered onto a support beam that runs full length of the wing keel. Then the pads are bought up to the hull. The beam supporting the keel is part of the cradle structure so uneven ground will not allow the keel to "sink", putting more weight on the pads over time.

In your case I would expect the keel should be supported to a height so there is minimal weight on the pads.


I think you got it. And use various thickness's of plywood at the pads so they are snug to the hull but not taking load.

Is that a wooden "box" raising the cradle off the ground? If it is, I wouldn't trust it. Looks like it could very easily collapse sideways.
Probably should be solid wood stacked for the hight. Our marina has bins of 6x6"s or 8x8"s for the purpose.
Is the cradle raised to make room under it for the keel? IE: Does the keel extend below the cradle? If so, that is scary.

Those blocks belong to the yard. They're starting to look a bit old and sketchy. I'll ask the yard manager if they can put some wood under the cradle to replace or as a backup. I don't know why this yard does it like this. The boat has been on the hard for two years. I bought it just before the oil canning happened