Is this a good porthole design?

[Tom1340]

Hello forum,
Is anyone familiar with this type of porthole? This photo is from a mid '90s Passport. I do not have experience with portholes that don't have exterior frames, and I'm wondering if this design is susceptible to leaking, and how difficult is it to replace gaskets?
Thanks for any comments,
Tom

[Hudson Force]

Many excellent portlights have this configuration. When you refer to replacing the gaskets, I assume this is on the plate of the opening frame that lifts from inside the cabin. This is usually a simple removal of the old gasket and inserting a new gasket within the groove of the frame with the seam at the top center. A bead of sealant is usually run around the outside where the frame meets the fiberglass. This sealant appears to be in need when viewing your photo.

[Mark1977]

Looks like a good place for water to sit and eventually leak.

[Pblais]

There are three seals. The seal between the glazing and the frame, the seal between the two parts of the frame that open and close, and the seal between the boat and the frame. Fiberglass. metal, and glazing all expand and contract at different rates. Over time they can all need to be replaced. The most difficult connection is between the boat and the frame as the cabin flexes as well as contracts and expands.

This type of installation can be tricky because a strong sealant won't flex enough and weak sealant breaks down. It would not be unusual for the best made ports to require some service. Appearances from the outside matter less if you don't have any leaks

Leaks normally can't be repaired without removing the port and doing a good job cleaning it up and rebedding the port. Attachment of a port to the boat is not about the screws and or bolts but the caulk. The screws and bolts just hold the port as the caulk sets. Mine have an outer frame but the frame really has no structural value. It is only cosmetic. It centers the port in the hole in the boat so it lines up as expected and hides where the over sized hole was cut.

[Tom1340]

Thanks all for your comments.
The seal I'm concerned about is between the porthole's metal frame and the boat's fiberglass. I fear applying sealant from the outside would not be durable or attractive. So it looks like pulling the porthole unit and rebedding it with sealant/gasket is the only way to go. Hopefully removing the unit is not a terribly destructive process.
Tom

[Pblais]

I fear applying sealant from the outside would not be durable or attractive.

Totally ineffective too. A little more caulk on the outside won't hold a port in or fix a leak.

If it is leaking now then pull and rebed the port. Don't use 3M 5200 it's not flexible enough! When you use the proper caulk you will be able to rebed them easier in another 12 years. It sounds a lot harder than it is. Some thin putty knives and a mallet can be used to slice out the port from the bedding. Cleaning the old caulk off of everything probably is the harder part. Use too much caulk so it gushes out just a little bit. Don't touch it until it is cured and you can cut it off clean with a blade. Smooshing it with your finger is a real no no.

[Wand]

This is a bit of a tangent but can folk tell me why (apart from tradition) ports open inwards? It has always seemed counter-intuitive to me (for cabin side, not hullside ports).

It happens that I'm replacing a leaky fixed port at the moment and I've knocked up a home-made version that opens out. The advantage seems to be that the seal between the fixed and opening parts doesn't have to be as perfect. My Mark I is far from perfect and yet it hasn't let in any of the wet stuff from the sky today. And unless I tackle the five capes, it should be the same for sea spray.

Under sail, outward openers could snag lines but ports don't need to be open when underway. Any other thoughts o wise ones?

[boatman61]

Originally Posted by At sea

This is a bit of a tangent but can folk tell me why (apart from tradition) ports open inwards? It has always seemed counter-intuitive to me (for cabin side, not hullside ports).

It happens that I'm replacing a leaky fixed port at the moment and I've knocked up a home-made version that opens out. The advantage seems to be that the seal between the fixed and opening parts doesn't have to be as perfect. My Mark I is far from perfect and yet it hasn't let in any of the wet stuff from the sky today. And unless I tackle the five capes, it should be the same for sea spray.

Under sail, outward openers could snag lines but ports don't need to be open when underway. Any other thoughts o wise ones?

Bloody shins when you forget its open one dark night... or even day time if your rushed...

[Pelagic]

I have 16 recessed portholes in the hull, which swing inwards to open.

(I think the primary reason they traditionally swing open is to have an internal securing point when opened and to make them easy to remove/replace at sea) (Also the shins)


They have a thick heavy formed rubber gasket inset on the window frame which closes on the thin edge steel collar that forms the recess from the hull. When hard pressed to weather, some are underwater but do not leak a drop as the heavy duty wing nuts compress the rubber deep into the collar edge. The whole arrangement is very heavy duty and solid..... yet simple.

The secret is to maintain the heavy rubber gasket by using a light oil to keep it flexible.

About every 5 years in the tropics I replace the gasket when the edges start to craze or crack.

You can see by the angle, there is no problem with water sitting.

I like this clean style because you have no corrosion issues due to external flanges and the recess is more forgiving in light rain for keeping rainwater out.

[GordMay]

Originally Posted by At sea

This is a bit of a tangent but can folk tell me why (apart from tradition) ports open inwards? It has always seemed counter-intuitive to me (for cabin side, not hullside ports)...

You don't have to remove insect screens (mtd on outside) to open them inwardly (from inside).
They don't obstruct decks.
Drip hoods on outside don't restrict opening.
...