Lewmar Hatch Perspex - Changing In Situ

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Hi,

My Lewmar hatches have tinted perspex which is crazed. I would like to change the perspex but not remove the hatch from the deck. It looks like the perspex is secured in place with an adhesive sealant. My thoughts are to buy replacement perspex pre cut and then fit after removing the old and cleaning up the frame in situ.

Anyone done this with the frames still in the boat? Why - well the interior has been refitted and the hatches were removed and re-bedded before the head lining and trim was replaced. Now, looking at the new headlining, and lovely teak trim the hatch perspex looks very shabby. I really don't want to remove the trim and headlining to access the under deck bolts. Yes, I know - shoulda, coulda, woulda - the story of my life.

Thanks,

BlowingOldBoots
 
They are the old style Size 30 Ocean Hatches with the 2 hinges (pretty sure), internal handles have the red locks on the inside and can be opened from the outside. A good idea though and will look at the hinges but if my memory serves correctly the hinge pins look pushed in.

Edit - Found a picture of one of the hatches: -

29584145523_5ef3049f7d_b.jpg

Image hosted on Flickr

You can see the pressed ends of the hinge shaft are oversized.
 
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If it's like mine there are 2 bolts on each hinge that hold the top part of frame and the glass. Undoing the two bolts and prising off the sealer will allow you to remove the top frame and leave the bottom part in situ.
 
BlowingOldBoots said:
They are the old style Size 30 Ocean Hatches with the 2 hinges (pretty sure), internal handles have the red locks on the inside and can be opened from the outside. A good idea though and will look at the hinges but if my memory serves correctly the hinge pins look pushed in.
Click to expand...

Are they Rollstops? I checked mine a while ago and these seem to be the identifying features:
height above deck 42mm;
lid clicks as lifted;
catch blocks NOT in corners of frames;
red* locking buttons inside handles;
NOT held open by stays.

* although probably pink by now ;)

Lewmar spares page here: http://www.lewmar.com/search/product/rollstop?field_hatch_type[]=301&lf=0&lt=4&f=1&o=d
(Although I'll probably get the glazing from Hadlow Marine when I get around to it.)
 
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I've done it to my Lewmar hatches twice - easily done in situ, but you must have the 9mm acrylic cut exactly to size. Cutting out the old Perspex needs lots of new Stanley knife blades.
I have found, over time, that normal silicone sealants are too short-lived to be worth using and one of the expensive urethane ones to be superior.
 
Have done a Canpa hatch in situ. So long as the weather is decent I can't see much benefit in removing it first.

Eagle Boat Windows did a kit with all the bits needed, and instructions.

Worked well.
 
PaulRainbow said:
It's not a good idea to stick the acrylic in with adhesive. The recommended product is a non setting butyl sealant. Such as : http://www.everbuild.co.uk/145-butyl-sealant
Click to expand...
I am always a strong supporter of butyl sealant whenever it is indeed possible to use it. In this case, I am afraid, I would not recommend it; the plastic part must be strongly secured to the frame of the hatch. An even remote possibility of becoming loose could - in quite unfortunate cases, I admit - lead to the sinking of the boat.

Daniel
 
You may find the hinges are secured with rivets to the body. If so these are easy to drill out. It could be done in situ but it would be a pain and far easier to remove the hatch, leaving the frame in place. I made up a board to place over the top, with a bolt through to a wooden brace that provides an excellent temporary weather proof cover. That way the hatch can be taken away and dealt with at your leisure!

I took out the old acrylic and had the local supplier fabricate using this as a template. It must be accurate and from memory has an addtional three holes to be cut in the acrylic for the hindges and latch. If you are lucky it shoud be a next day service.

It is straight forward to re-assemble if a little time consuming. I used black Sikaflex to bond the acrylic to the frame and then replaced the rubber seal. You need to be very careful how you apply the sealant so as not to leave a messy sealant line that is visible through the top of the hatch. Also be very careful to make certain it is a complete seal as the slightest defect will weep water. You may have an issue sourcing acrylic of exactly the same thickness. In that case opt for slightly thicker acrylic as it is better to be slighly proud, than the opposite as water will pool on the surface.

When all done invest in a canvass cover as the prolonged exposure to sun will cause the same damage again I suspect! Persoanlly I changed to clear as well, which I find much nicer than the tinted, but each to their own.



Once set the whole thing can be reassembled.
 
Have a word with the very friendly and helpful couple at Eagle boat windows.
They hold patterns for all standard hatches for your new glazing.
Also very knowledgable about correct adhesives/sealants as they do most RNLI replacements.
No connection but a very satisfied customer for a number of jobs!
 
291 or 295 I think will have to check the tube to see which I used. If you Google there are a few leads (and also I think on YouTube). I seem to recall one is also more UV resistant which given the amount of sun exposure seems a reasonable precaution.

On the Lewmars I am sure I am correct in saying the Acrylic is seated on the lip of the frame so of course "inserted" from the top, so the sealant is not all that structural anyway.

I found the answer was to apply masking tape around the edge of the acylic before inserting it in the frame (which is the one aspect this video isnt clear on) but is otherwise a very good tutorial.

https://www.youtube.com/watch?v=eD3Hp8W07yY

I also chatted to the guys at Eagle who I thought were very good. However with a bit of time and patience it is a job you can do yourself securing a very significant saving (and of course hassle sending off hatches and waiting for their return). I dont criticism them for their price because if you allow maybe a couple of hours for a large hatch you will not be far out and they should be paid for their time and skill.
 
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charles_reed said:
I've done it to my Lewmar hatches twice - easily done in situ, but you must have the 9mm acrylic cut exactly to size. Cutting out the old Perspex needs lots of new Stanley knife blades.
I have found, over time, that normal silicone sealants are too short-lived to be worth using and one of the expensive urethane ones to be superior.
Click to expand...

Use a silicon made for this: DOW 795. Nothing else come close and it is probably what the factory used. Sika 295 urethane requires primer. I've used both and prefer DOW 795.
 
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Did this job last year... are we sitting comfortably? Then I'll begin.

Removal of the old is easy, run a craft knife around from the top and underneath. Start worrying the corners until you get a rip running along the old sealant. then by inserting screwdrivers prise off the old.
Next, remove the old sealant./ This a bugger of a job, the best tool I found was a wooden sprung clothes peg, the channel for the sealant had been finished deliberately rough and hard anodised, the wooden peg fits the groove just nice and wont ruin the finish (which is good for keeping the new seal in place). Then its acetone or nail varnish remover (same thing just smelly), very long winded. Some advice is to get a soft blade (edge of credit card style) to peel up the old sealant, if the surface is good and well prepared, this wont work.
Now to prepare the new perspex.
Keep the protective film on till last! Place the new perspex in the frame, space it out evenly with shims (matchsticks at the corners works well). Put masking tape round the top of the rim one to mask off the shiny and 2... mark the masking tape and protective film with lines mid way each side so you can see the alignment next time you place the perspex without the aid of the shims.
From underneath score the protective film in line with the edge of the rim, remove the perspex and peel off the film border you have just cut (this border will touch the new gloop). While you are ferreting around down there, mask off the frame shiny bits.
Run a bead of Sikaflex (have to get back to you with the number) round the rim and drop the perspex in aligning it by the marks you made earlier. Press it in evenly (and this is the tricksy part), dont over do it at the corners, press along the edges, but keep clear (about 4 to 6 inches) from the corners. Reason is that the corners are more rigid and if you press there, the middle of the edges will bow up and a few months later the corners will lift. Using a plastic scraper smear off the excess around the top, the protective film on the perspex and the masking tape will keep the shiny and clear bits shiny and clear (respectively)
Wait 2 or 3 days and only then cut off the excess gloop underneath.
Now you can remove the protective film and scream because you have put it in with the handle holes in the wrong end.
 
Some very good tips and information. Thanks everyone, I appreciate your advice.

BlowingOldBoots
 
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