How to fix a bent hatch?

[jeanette]

Vandals have recently bent my Lewmar aluminium hatch by levering it with a blunt instrument. It's a 24" Superhatch and the centre of the leading edge has been lifted approximately 1 inch. It now provides good ventilation and will leak when the weather goes back to normal. The perspex is undamaged although it has parted company with the sealant and will need to be reseated.

Does anyone have any ideas how it might be repaired? The only opinions I have had to date are

a. replace it with a new one and safe yourself a lot of bother;
b. try and get it straightened out.


Can anyone tell me if b is a practical suggestion and how it might be done or who might have the capability?

The boat is moored in Poole.

Thanks very much


<hr width=100% size=1>Jeanette

 

[MainlySteam]

Assuming the aluminium is just bent with no tears or stretching, my first reaction would be to try a good motor vehicle panel shop.

John

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[ccscott49]

You may find the aluminium of the frame has work hardened, when it was bent and will probably break if you try to straighten it, but whatever you do, yopu will; need to remove the perspex, then anneal the alunimium and straighten, then refit and seal the perspex, to anneal aluminium, you need to heat it, until the unburnt end of a matchstick, leaves a brown stain when rubbed over the surface, then allow to cool, the ally will now be soft enough to work. hatches are expensive, its worth a try to repair it first.

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[Aramas]

It's impossible to know whether it's worth repairing or not without looking at it. If it's only bent at one place then it would be easy enough to straighten, but if it's a 'wiggly' kind of bend then it probably isn't.
If you have to pay someone to straighten it, it might be worthwhile trying to source a new frame from the manufacturer, as labour can be quite unreasonable theses days.
Bear in mind that once aluminium has been bent and straightened, it becomes work hardened, and hence more brittle and prone to fatigue cracking than the surrounding material. The bent area will be stiffer than the surrounding metal, so trying to straighten it over a broad area will probably put new bends next to the old ones. Whether or not that would be an issue depends on the severity of the bend.
If the bend is fairly minor, just remove the perspex and fittings from the frame and see what you can do with it. Don't just try to straighten it with your hands - you'll just make more bends. For localised damage, use bits of wood and a hammer, and try to belt the twisted bit straight. Bits of metal work better, but also mark the fitting. You might be able to clamp it in a vice with the bend adjacent to the edge of the jaws and straigthen it that way.
Good luck with it.

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