Replacing the forehatch

February 9th, 2011 Leave a comment Go to comments

By Jo Lloyd, Lammergeyer

I fitted a replacement GEBO hatch recently – here’s the wrinkles i found with mine.

It’ll take about half a day and it is one of the better through deck jobs as it can be done by one person. The longest part is the cleaning and the waiting for epoxy to cook off. The interior flange does come lower than the old hatch but ho hum.

1. Your old hatch may be a swine to get off – depsite the leaks mine was stuck down much better than I expected. As the thing was leaky, I ended up taking the decision to destroy it – having had vague thoughts before I started of offering it on eBay.

Eventually I prised the lower edge up (using progressively larger screwdrivers as wedges – they’re old ones kept for the purpose) and then using two of the big wooden yard wedges that they use to adjust boats in cradles as larger wedges. Then the hammer came into play and I had a great 5 minutes battering the old hatch off. I did have one small piece of gel coat lift but nothing too bad – less than 1cm square. The old hatch was badly bent when it came off and I took great pleasure in dropping the thing over the side into the bin.

2. Headlinings – you’ll need to take back far more of the headlining than you expected. Allow a good 6″ all round – not so much for dropping in but for spanner swinging room when getting nuts off/on. It also helps if you tape the dangling headlining back to itself to keep it out of the way.

3. A bent end ring spanner or an extended bar from a socket set is the easiest thing to use. If you use the socket set bar, be careful when tightening up that you don’t shear the bolt.

4. The new hatch literally does drop straight in – however, before you get excited, the screw holes are not in the same place.

I filled the old holes with epoxy and cooked it off there and then by applying copious amounts of heat from the boat’s hairdryer – do not scoff, chaps. A powerful hairdryer is one of the most useful things a girl can have on her boat – it does loads of things and you can even dry hair with it too! And yes, I do have shore power fitted to my Impala – not so much for cruising in the summer but for in the winter when she’s on the hard standing & running the heater, lamps, power tools etc.

You may choose just to seal the old holes with the new sealant when you fit the new hatch, in which case ignore this.

5. It uses 16 countersunk M5 x 25mm nuts and bolts. You could use 20mm but there’s not a lot of bolt on the other side. The interior flange comes lower than the protruding bolts anyway.

6. When you draw round the new hatch and its holes for masking for the sealant – come out a good 3mm on all sides but the hinge side before you mask. I had huge trouble getting the masking tape off as the edges of the hatch had sealed down over it. Do NOT mask under the hinge side AT ALL. You cannot get under the hinges when its fastened down to get the masking off and you end up with Sikkaflex absolutely everywhere – including in the hinges!!

7. Wear a boiler suit or something that you don’t mind getting Sikkaflex on – when you are standing in the hatch space, fastening it down, you’ll brush against the sealant somewhere.

It was a much simpler job than I was expecting – the only real hazards were the rain shower in the middle and the know-all on the boat next door who kept trying to tell me how to do the job.

Most Impalas started off with Houdini hatches. These are still available, but are lightweight. Gebo and Lewmar hatches are more sturdy, but the lewmar one has different corner radii. On Polly, we built the surround up with glass and tape to match the new hatch.

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