Repairing Large Deck Crack

The deck between the seat area and the round hatch on my Hobie Quest has been developing a crack for some time now. It started as a small crack and got bigger and bigger. I drilled a small hole at the end of the crack to keep it from getting larger but that just caused another crack to form. Pretty soon it was no longer a crack, but the deck around the hatch had broken into pieces. I tried to repair it a couple times by plastic welding, but the cracks soon returned.

The problem is that the hatch is a hole in the deck. A foot to the rear is the seat, which supports all the weight of the paddler. This area of the deck is unsupported and the hole for the hatch makes it a weak area. Over the years, the constant flexing of the unsupported deck, along with exposure to UV radiation caused cracks to develop around the hatch. While this area of the deck could have used a little more support, this kayak is over ten years old and gets more than average use, so "wearing out from age and use" would be more the reason for this as opposed to a design flaw or defective materials.

Nothing else wrong with the kayak, so I made another effort to plastic weld the cracks and try, one more time, to fix it for good. I held the broken deck pieces together with the lower ring from the kayak hatch, then did the best welding job I could do with an 80w plastic welder from Harbor Freight. This particular welder had been run over by a 40 ton semi truck and still worked, so it is well worth $15. The key to good plastic welding, just like any other welding, is to bond materials to each other, not melt a layer of plastic over the top.



Now, it doesn't look all that great, but there were two three inch cracks from the hatch opening towards the seat and the hatch "lip" was broken in three seperate pieces. The hatch "lip" was broken away from the rest of the deck along a ten inch crack. The welding job seems pretty good even though it looks like crap. As long as it holds, I don't care what it looks like.

After the welding job, the deck and hatch "lip" were not has smooth as they were from the factory, so I used a little bit of JB Weld to fill the gap between the hatch and the deck. I had used Lexel and silicone seal in previous repairs. They were watertight, but were not very strong. I'm hoping the JB Weld will do a little better job.



Since the crack was caused by the unsupported deck area flexing, I had to do something to mitigate that or the crack would most likely return, regardless of the quality of the welding job. I got a basketball, deflated it, stuck it through the hatch and placed it between the seat and the hatch with the air valve easily accessible. I filled up the basketball until it supported the deck with me sitting in it, but not so full that it would push up on the deck. This is essentially an air shock or load leveler type air bag for the kayak. I've been using the basketball with the deck completely broken and it supported my weight, so I'm hoping that will continue and prevent the deck crack from reappearing.

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Waterman at Work - Kayak Fishing Photos, Video,Kayak Rigging - Blog

Great repair! Love the basketball bladder.

A disadvantage of supporting the deck of your kayak with a basketball is that the basketball will inflate and deflate with changes in temperature and altitude. For example, if you drive to a launch site in warm sunny weather, your kayak and the ball will heat up, and air in the ball will expand and push up the deck. Then when you put your kayak in the water, the kayak and the ball will cool off, and the air in the ball will contract and the ball may be barely supporting the deck.

Rafters are familiar with this problem. When a raft is sitting in the sun on the shore at a launch site, the raft may get very firm and feel over-inflated. But as soon as the raft is put in the water and gets splashed by waves, the raft may get flabby, and the rafter will need to pump it up. Then when the rafter stops for lunch and pulls the raft up on shore, he or she may need to bleed air out of the raft to prevent damage from over-inflation.

I suggest that you obtain some ethafoam or other firm closed-cell foam and cut a block of foam which you can jam inside your Quest to support the deck. The foam won't be affected by changes in temperature. Whitewater kayaks have blocks of closed cell foam in the front, between the kayaker's legs, and in the back behind the seat, to support the deck of the kayak and to keep the kayak from bending and entrapping the kayaker if the kayak gets pinned on a rock.

Pool noodles work well also. Cut a little oversize and trim to correct height. I use 3 wooden skewers in the noodles to stablize them from warping, and tack in place with a smear of silicone calking. The skewers are cut slightly shorter than support height so no hull contact is made.

I see.

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Waterman at Work - Kayak Fishing Photos, Video,Kayak Rigging - Blog

Wow! Great effort bro... really would be helpful for any future crack I would get... thanks for sharing yah!

Nice job on the repair! Who cares what it looks like as long as the weld is done properly. I agree with what has been said regarding the foam blocks. They work a lot better. If you can't find them use pool noodles but tape or glue three of them together then cut to proper length. Place several sets (of three pool noodles glued together) around the hatch. This will add strength without running the risk of a wood dowel poking through the hull. If you use tape I'd recommend Gorilla tape (black). For glue I've had really good experience with Amazing Goop Marine (170011) Adhesive.

Take care.

I forgot to mention, for a major crack like this, it's a good idea to use metal screen and melt it into the plastic across the cracks. It adds a lot of strength.

The basketball was chosen because it has to support about 190 lbs., depending on what I'm wearing and how many burritos I've eaten in the past 24 hours. The air pressure in the basketball is adjustable. Also, all the repair materials needed to be readily available at local stores like WalMart and Home Depot. I only get into a big city a few times a year.

The basketball also has a history of maritime rescue. According to local legend, a sportfisher out of San Diego was running off the coast of Baja when it hit something and sheared off the sonar bulb on the bottom of the boat. Water was coming in quicker than the bilge pumps could handle and the ship was sinking. A Coast Guard chopper from San Diego flew out to the boat and dropped a basketball and pump to the sinking sportfisher. The crew stuck the basketball in the hole in the bottom of the ship, pumped it up and stopped the leak enough so the bilge pumps could handle the remaining water and allow the boat to limp back to San Diego.

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Waterman at Work - Kayak Fishing Photos, Video,Kayak Rigging - Blog