Parrallel Hull Cracks

[MSN-Oday]

Hello all,
New to ODay and our first "big boat"
On our 84' ODay 26'...
Just took a look under the boat while on the trailer and found two cracks. Below the water line on the bottom of the hull. Running length wise. Near the center of the hull about where the trailer wheels are. Each crack is about 2ft. Each crack is about 2ft out from the keel. They are almost in the exact spot on each side. They do not seem deep. I can't get the tip on my pocket knife in more than a millimeter. I feel that somehow the weight of the boat on the trailer caused this. The cracks seem (at least to me) that they are from a bowing or bending moment/pressure.
Is anyone familiar with this?
How did this happen?
What is the fix?
Thank you very much. We appreciate all the help. -Scott & Derek -Madison, WI.
Hope the pictures upload.

 

[LeeandRick]

Is the keel touching the trailer? With your description I would think the bunks are carrying too much load or not enough load. Also the trailer could be flexing in the center. Can you see this area from inside the boat?

 

[MSN-Oday]

LeeandRick,
Yes the keel is touching the trailer. I do feel that the bunks are tracking too much load by the looking at the location of the cracks. I do believe I can see this area from the inside (was the first thing I looked at after I discover the cracks). There is no indication of cracking I could see from the inside.
Thank you for responding,
Scott & Derek

 

[njlarry]

I am not a surveyor but I agree the inside picture will indicate how structural it is. Good news is fiberglass repairs are well within diy capabilities. Should not be hard to fix. You will find a lot of good info here using the search function. Also are a lot of great fiberglass repair videos on YouTube by boatworks.
Good luck. Let us know how it goes.

 

[MSN-Oday]

njlarry,

Thanks for the confidence...
Do you guys think it is ok to repair on the trailer? I really do not have the access to boatyard lifts.
Thanks Scott & Derek

 

[LeeandRick]

Are the bunks adjustable up and down? How about a picture of your keel support area end to end. If I have a better idea of your trailer setup I might (might operative word) be able to give some advice on setting the bunk height to keel rest relation. Fix the culprit before repairing. Repairs will require a couple of test to determine the extent of the damage. More than likely, depending on the thickness of the bottom paint, its just a gel coat fracture.

 

[MSN-Oday]

I will post more pictures tomorrow of the trailer setup. I don't think it is adjustable when the boat is on the trailer. She'd have to come off. Maybe. I will look carefully tomorrow.
Thanks Scott & Derek

 

[njlarry]

Trailer should be a great place. Either remove both side bunks after stabilizing with jack stands or 4x4s or do one side at a time. Most of the weight is on the keel. You want to keep that way while working on it. Ask others who are in your area to take a look at it.

 

[MSN-Oday]

Here are a few pics of the trailer. Sorry for the lighting it was still dark when I left for work... I have never adjusted the bunks. Hopefully I can lower them.

 

[LeeandRick]

I can't see parts that well but check the cross members under the keel where the cross member has been cut and lowered. There does not appear to be much overlap so check the welds for cracks. Is there threaded rod above the towers on the bunks? The trailer looks like it's been modified a few times.

You might sand a small area 1"x 1" over the crack to see how deep it goes.

 

[MSN-Oday]

Update:
Yesterday I was able to lower the bunks. The cracks seem to diminish or they were not as wide when more of the weight went on to the keel. Today the plan is to sand or grind out the cracks to see how bad they are. I will send pictures when that is complete.
Thanks Scott and Derek

 

[Ron20324]

I suppose it would be hoping for too much that the crack is just in the many layers of bottom paint?

 

[agprice22]

Maybe just start with a dremel to see if the crack ends at the gelcote or if it enters the fiberglass. If you widen the crack with a dremel cutting bit, you can see how deep it goes.
It may just be cracked epoxy barrier coat or gelcote. If it is deeper, you can do a fiberglass repair.
Check youtube. You can do a water test or use a light from inside to see if the crack is theough the hull. If it is only a shallow crack, fill it, fair it, barrier coat it, and bottom paint it.
Did the keel bunk on the trailer change? Rot? I have seen oil can dents under the bunks on hulls where bunks were too high, but they were harmless. Yours seems to point to stress on the hull closer to the keel, like the keel wasn't on the bunk fully, or the bunk rotted and compressed.

 

[MSN-Oday]

Went at the cracks today. I lowered the bunks. They were positioned high and had a lot of weight on them. Sanded down the bottom paint to reveal the cracks. Started in with my Dremel 732. Ended up taking 1/4" to 3/8" out of the hull before the cracks were gone. The aft port side had a deep crack and I put a hole through.
-So far what I have learned is. #1- I am learning a lot. #2- I will wear a scuba mask the next time. #3- I will buy a better dust mask. #4- You need to be a contortionist to crawl around under this trailer. #5- Check the dang bunk height before you buy and tow a boat 350 miles home. #5.5- I'm not done learnin yet...
Thanks- Scott & Derek

 

[agprice22]

There may have been a problem with the layup from the factory. Factories do not always get it right. If they let it cure too long before applying the next layer, it might not have bonded. O'day has a good reputation as a well built boat at that time. Make sure the boat rests on the keel on the trailer, not on the bunks.
Now you will feather those out about 4 to 5 inches away from the crack. Feather so you have a deep, wide area to build up. Use compressed air to blow it off. Clean it with acetone, and begin a layup of fiberglass and resin. If you add each layer after about 30 minutes, you can keep adding. If you let it cure, you should wash it with soap and lightly sand it when it is dry between each layer. When done adding layers, you will sand it fairly smooth, but don't remove too much. Then fill it with a filler for use below the waterline to shape the repair to conform with the hull and a little more, so it has a little prominence. Then sand the filler smooth to conform with the hull.
Then add a couple coats of epoxy barrier coat. Then add bottom paint. All done!
You can use a heavy fiberglass cloth for the first layers. Then you can use lighter for the last. You can use chopped strand mat for the last 1 or 2 layers to create a smoother surface for sanding and filling and fairing. Woven fiberglass cloth will print through the epoxy and force you to sand a lot more to remove the gloss for adding filling and fairing, so chopped strand mat helps eliminate that. Wet the surface with epoxy liberally before adding cloth. Use a roller wheel to squeeze out bubbles. Don't use a scraper to squeeze out bubbles, it will remove too much resin. Buy a box of vinyl gloves! You are gonna go through them!
When sanding, use a dust mask and safety goggles. Use a strong floor fan to keep your goggles ventilated and to keep the dust flowing away from you. It helps a lot. A vacuum attached to an orbital sander works well too, even when sanding upside down.
It'll take you a day start to finish. Looks like a fun project! Good times!

Andrew

 

[wing15601]

It appears from the photos that the cracks are along side the keel. It also appears that the cracks are opening up which would make me think there is too much weight on the keel. If that were the case there would be some indication in the bilge, with supporting structure distorted or cracked. It also could be that I'm completely wrong but it's something to think about.