Decreasing the size of a hatch cut out?

bumblefish

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OK, so I am not likely to find the correct size hatch for the hole in my cockpit floor. How can I go about decreasing the size of the hole?
 

alienzdive

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What is the floor made of, cement, glass, steel, wood?

Could be easier to cut a bigger hole and put in a largetr hatch than re-build a hole. Depends alot on construction type?

Custom made hatches are available too.
 

oldsaltoz

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G'day Bumblefish,

I may be able to help but I need a bit more info as I don't think we have ever worked on an Elizabethan 30.

About what size is the existing hatch and is it a retail type or one the builder built in?

How close to the sides and ends is it?

What material is it made of and what is the rest of cockpit floor made of?

If the reduce the size, will you still be able to lift out the engine?

Avagoddweekend......
 

matnoo

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Posting a photo of what youre talking about would be a great help! You got any.

A good tip, when taking pics to work from, leave a 1meter rule somewhere in the picture so you can take rough measurements afterwards at home!

Mat
 

bumblefish

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The 'hole' has been cut into a solid GRP floor. It is about 400mm by 450mm and there is probably 120-150mm on each side up to the cockpit lockers. There is a wooden rectangle around the hole and a wooden lid with a rubber seal to close it. The engine will come out through the companionway. I can not find an off the shelf size hatch to fit, other than one which is not suitable for cockpit floors. If I can reduce the size than I can fit a standard hatch. The GRP is solid, about 1cm thick.
 

Bajansailor

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Do you need to get into the compartment underneath from the cockpit on a regular basis?
If not, it might be viable to just bolt a cover panel down - if you use captive nuts on the other side (eg the 'Bighead' type or similar), then you can un-do the bolts singlehandedly.
 

Robin2

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That sounds to me as if there is a raised lip around the hole and the present lid has a downward lip that fits outside the raised lip - to keep the water out.

I think it would help if you said why you want to change the present arrangement - bright ideas might then spring to mind.

I assume you do not want a transparent hatch.

Could you do a sketch of the existing arrangement, and another one showing what you are aiming for?
 

bumblefish

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The raised lip is only formed from the wooden frame, if I removed that I would have a flat surface with a hole! I want to change this because the existing lid is old marine ply in not very good condition and I want a to have a more substantial hatch arrangement. I was planing on fitting a watertight hatch and arranging a teak grid over this. The hatch gives access to the stern gear, batteries and gear box, so access is fairly frequent.
 

ShaunG

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Would it be possible to mould a GRP blanking plate to cover the hole and then cut a recess in the new facing plate for an off the shelf hatch? It would be fairly easy to mould a good looking GRP blanking panel and you should be able to achieve this in an afternoon and and about £20. There is plenty of info on the forums on creating a simple GRP moulding, or feel free to contact me for a walkthrough

Regards

Shaun
 

Robin2

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The raised lip almost certainly adds a lot of stiffness to the floor. I would be slow to remove it.

Why not make a new marine ply hatch and cover its external surface with glass cloth and West System epoxy. With a little care it will then look like plastic. And if all the wood is well covered with epoxy it will 'see you out' (as my mother has been saying about everything she gets for the last 20 years)
 
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