Magnum with deck being ripped of at front cross bar

Looking at a Hobie 18 Magnum that looks recoverable but for the 8" to 12" long lip cracks on both hulls inside and outside edges. Has anyone seen this and taken this fix on. It seems like it would be difficult to grind out someones poor attempt to repair them and then build enough adhesion between the deck and the hulls with the molding for the cross bar fully in the way. I have lots of Carbon and fiberglass experience but before I buy this boat I'd like to hear if this is typical and fully repairable. Lastly can it be done through the ports or do I need to cut open the hulls to get enough access. I hate to see this old boat turn into a parts for sale package. Shipping the parts from Hawaii to buyers is hardly worth the effort. Is the failure just from the weight of the hulls pulling down away from the cross bar or just that they want to twist away?
Anyone with experience please Comment.
Steve

Hello Steve and welcome!

Based on your description, I'm having a hard time figuring out just where the cracks are. Are the cracks in the deck or side of the hull? Or are they in the lips themselves?

It sounds to me like the "cracks" are simply a separation in the hull lip, running longitudinally on the underside of the lip (at the edge of the lip). However, separation in the hull lip is fairly typical after ~30 years. The glue that bonds the deck to the hull just tends to start letting go. 8-10" is minor, but you'll still want to fix it. The area just forward of the forward crossbar is a critical high stress area, so any damage there needs to be addressed before it gets worse. (You've got the forestay & bridle wires pulling up and in at the bows, while the mast and forward crossbar is being forced down in the center, which means the hulls experience a significant bending moment and shear force just forward of the forward crossbar. The keels are in tension, tending to pull apart and the decks in compression, tending to buckle).

The fix is simple enough, and doesn't require new glass. You'll want to take the trampoline and crossbars off of the boat and flip the hulls upside down. Mix some epoxy and use a screw driver to open the separation up slightly to inject the epoxy into the gap. Pour in enough to ensure good bondage between the hull and the deck, and then clamp the lip together while the epoxy cures. I had to do this just last year, down about half the length of one of my hulls on the outboard side.

If I were considering this boat, I wouldn't discount it on that basis alone, but it would make me want to look closer. Check for soft spots in the deck or sides of the hulls. Check for water sitting in the hulls, and take a look at the bottoms of the hulls to see how worn they are. If you can, get a ride on it for an hour or so and see if there's any water leakage in the hulls. The boat could still be in very good shape, as they all get little things here and there as they age, but it's worth checking just to make sure that there aren't bigger problems.

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Mike

'79 H18 standard 'Rocketman II' sail #14921 RIP
'78 H18 (unnamed) sail #14921
'08 H16 sail #114312
'97 H21SC sail #238

The "D-shaped" brackets are advisable, especially with wings, but a lack of them doesn't mean the boat is no good. To be clear, there are a few "variants" of the Hobie 18. The Hobie 18 standard and Hobie 18SE (Sport Edition) didn't have any wings. The Standard had clear anodized aluminum (looks silver, like mine), SE had black anodized aluminum. Then the Hobie 18 magnum came out with black anodized aluminum and wings, followed by the Hobie 18SX with a taller mast and longer, "SX-style" wings. To make things more complicated, magnum or SX-style wings can be retrofitted to any type of Hobie 18. Not sure if the one you're looking at has wings or not.

Getting back to the question about the cracks, do you have any pictures or sketches/diagrams of where the cracks are? They could be tremendously helpful. If you do, uploading them to facebook or photobucket and then posting links on here is the easiest way to share them, as you can't upload pictures directly to the forum. The 18 is a fantastic boat, and given the choice between fixing a banged up 18 and picking up a good 16, I'd stick with the 18. Then again, it depends on the extent of the damage and necessary repairs.

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Mike

'79 H18 standard 'Rocketman II' sail #14921 RIP
'78 H18 (unnamed) sail #14921
'08 H16 sail #114312
'97 H21SC sail #238

I agree, pictures are really needed to provide an accurate recommendation. I'm having a hard time visualizing where the cracks are from the description.

sm

based on your two threads, it sounds like cracking along the deck/hull seam. The D shaped reinforcing plates were added to H18 production to prevent that kind of stress on the hulls at the crossbar and are a necessity to be added. if the cracks are in the area of the front crossbar you should be able to access repairs inside through the ports without cutting new holes in the deck, which should be avoided in front of the crossbar. In fact if they are OEM ports, take them off to give you even more arm room inside. then replace with the more waterproof screw-in ports.

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Chris
'88 H18SE Arís