Portlight gaskets

For those that have replaced them....

What measurement did you use to purchase?

My ports have gasket grooves are 11/32" wide, but closer to 1/4" deep.

The gasket material I am looking at is 1/4 or 5/16 or 3/8.


Thoughts?

One option:

Portlight Gasket Seal - Hollow Black Rubber - Port Hardware & Parts - Ports & Hardware - Ventilation - Downwind Marine

Another option: I found a direct replacement by going to a gasket shop in AJX. The stuff is pretty hard and doesn't compress as well. Next time I'll try the stuff from Downwind.

Larry M said:

One option:

Portlight Gasket Seal - Hollow Black Rubber - Port Hardware & Parts - Ports & Hardware - Ventilation - Downwind Marine

Another option: I found a direct replacement by going to a gasket shop in AJX. The stuff is pretty hard and doesn't compress as well. Next time I'll the stuff from Downwind.

Click to expand...

I have been saving that link for 2 years waiting till I got to the portlights project....

Just trying to decide which size will be better.

Sorry I miss read your post. I used 3/8". As it went into the portlight, I stretched it and it fit pretty well.

I just replaced several of mine with 1/4 OD Buna O ring cord stock from McMaster-Carr. 20 ft was $15 including shipping.
The hollow stock would probably fit better (if I found that I would have gone that route), but this works fine.

jleonard said:

I just replaced several of mine with 1/4 OD Buna O ring cord stock from McMaster-Carr. 20 ft was $15 including shipping.
The hollow stock would probably fit better (if I found that I would have gone that route), but this works fine.

Click to expand...

Sounds like the 5/16 would be OK then...just let the adhesive fill the tiny width gap.


Thank you.

Larry M said:

Sorry I miss read your post. I used 3/8". As it went into the portlight, I stretched it and it fit pretty well.

Click to expand...

Thanks....tempting to go 3/8...hate to have to stretch it to make it fit...

The 5/16 will be above the flats and I would think the 1/8 inch lip or so might have a hard time with 3/8 ...but without knowing your port grove size...it will still be a best guess.

PS, the portlight manufacturers make the groove slightly smaller than the gasket. They want you to do what Larry did and stretch it as it goes in. As the tension goes off, it expands and locks itself into the groove. I would guess that yours was designed for 3/8" wide rubber. A little 3M Weather Strip Adhesive in the groove is a good idea also.

I don't stock it any more or I'd mail you a couple of feet to try it.

HopCar said:

PS, the portlight manufacturers make the groove slightly smaller than the gasket. They want you to do what Larry did and stretch it as it goes in. As the tension goes off, it expands and locks itself into the groove. I would guess that yours was designed for 3/8" wide rubber. A little 3M Weather Strip Adhesive in the groove is a good idea also.

I don't stock it any more or I'd mail you a couple of feet to try it.

Click to expand...

Hey thanks!!!

I have a list of stuff you can mail me so I can try it for a decade or so...

With the groove only a 1/4 inch deep and the gasket hollow, when squeezed sideways from 3/8 to 5/16...it would be sticking WAY up. The port has a knife edge designed to go into the gasket....hmmmm...the dimensions are just bugging me.

Not that I don't value the input...it is just setting off my "you don't have the right stuff" alarm in my head and in my mind's eye I see when it's all assembled and glued in....the port doesn't shut correctly.

Dang old boats and their equipment is fun!!!

PS, do your hatches look like mine? If they are the same, hurry up and figure this out. I need to do the same job on mine.

no...mine are bronze ovals...


because the knife edge sealer on my ports...everything from 1/4 inch like Jay used to 3/8 like Parks suggested will probably work.


But holy cow...1/4 inch deep, 11/32 wide.... and 1/4, 5/16 and 3/8 gasket material.


Sure...I am just gonna flip a 3 headed coin and order...the worst scenario is it costs $25 less shipping...and I can't modify it to work.


But thanks to everyone!!!!!!!!!!!!!

fryedaze said:

PS, do your hatches look like mine? If they are the same, hurry up and figure this out. I need to do the same job on mine.

Click to expand...

Mine looks like yours so who goes first?

Measure up and order from the above link...easy enough except for guessing the right size if the measurements are different enough from stock sizes....

Soft , plastic or large thin metal do bestwith Sq rubber gaskets that are hollow internally.

These keep someone from bending the frame when over tightening .

Better opening ports , ship grade 12in + ports ( 3/4 + glass) can use old style flax stuffing box packing , and it will last for decades.

As a follow up to this thread..
while replacing one of the gaskets one of the thumb nuts was tightened a little too much and it broke thru the hole that holds it in place.
I apologize that I don't have a picture of the portlight, but I found a replacement screw on the McMaster Carr website.
The 1/4 -20 by 2 inch length "machine screw hangar" fit perfectly after a little filing of the corners.
A 10 pack cost $13.55 so I consider that a great find. Thought I'd share.

The other alternative was to try to make one from a bolt.

Greetings,
Mr. jl. Great tip. Thanks. Good ole' McMC....

One source ,

Portlight Gasket Seal - Hollow Black Rubber - Port Hardware & Parts - Ports & Hardware - Ventilation - Downwind Marine

I have a 42 foot Bestway Labelle and it has rectangular Manship portlights on it,


The gasket is U shaped, all the replacements I have seen are fully enclosed ( tube like) anyone have any experience with replacing the old gaskets ?