Leaking port lights

[GJohn]

I recently purchased a 1987 Hunter 23. It has several topside leaks which I am tracking down. Water is coming in from both port lights. I plan on sealing them this weekend. Boat life life caulk was recommended by a friend but boat life website does not recommend life caulk for windows. The web site recommends life seal. Any thoughts on which to use. Also, are the port light attached from both exterior and interior. In other words do I need to remove interior teak trim. Thanks.

 

[dlochner]

If the frames are plastic, do not use Life Caulk, it is a polysulfide caulk that does not play well with plastic. The best choice might be butyl tape. https://shop.marinehowto.com/products/bed-it-tape

 

[jssailem]

This will depend on the port you have.
If this is a port with mechanical holding then butyl is a viable product.
mid this is the rectangular looking plastic window on the Hunter, then it will need an adhesive caulk to hold it in place. That application I understand is best accomplished with Dow795.
Just adding more caulk to the outside is a temporary at best solution. To solve the issue you need to remove the port. Clean everything of sealant. Repair any damage. Then install the port. There are YouTube videos of successful installations.

Here is the Dow application statement:

• Weatherproofs substrates such as glass, aluminum, steel, painted metal, EIFS, granite & other stone, concrete, brick, plastic

 

[GJohn]

I have not seen this method with the tape. I will look into it. Thanks

 

[ontherocks83]

This is a sealant and an adhesive that works well.

https://www.amazon.com/Sikaflex-291-White-Polyurethane-Adhesive-Cartridge/dp/B007H2R9SK/ref=sxts_sxwds-bia?gclid=EAIaIQobChMI3dbEpvrD5QIVN__jBx2YSAGREAAYAiAAEgKsCvD_BwE&hvadid=176372069248&hvdev=c&hvlocphy=9001871&hvnetw=g&hvpos=1t2&hvqmt=e&hvrand=9809915774854641951&hvtargid=aud-646675774026%3Akwd-4163416717&hydadcr=25239_9775708&keywords=sikaflex+291&pd_rd_i=B007H2R9SK&pd_rd_r=1a76c890-d7da-4459-9ce4-4fefb125d6c8&pd_rd_w=mXO7L&pd_rd_wg=N7fsy&pf_rd_p=a5491838-6a74-484e-8787-eb44c8f3b7ff&pf_rd_r=D2YZ57NWFBG2HXM05CM4&psc=1&qid=1572437547

 

[rgranger]

The best choice might be butyl tape. https://shop.marinehowto.com/products/bed-it-tape

 

[DArcy]

I don't know if butyl tape is a good way to mount windows. You need a rigid backing to compress the tape properly. Even if you have mechanical fasteners (screws), if they are not closely spaced you may cause additional stress between the screws which could bow or crack the window if there is no outer frame over the acrylic. I'd go with the Sikaflex or DOW adhesive/sealant. I used Sikaflex when I replace my windows and there were no fasteners, just bonded in place with the sealant. In order to ensure a consistent bead thickness between the acrylic and the frame, I used small pieces of double sided foam tape to hold the acrylic in place while the adhesive set.
Also, if you are removing the windows, you might as well replace them. They don't last forever and they don't cost all that much. I just took mine to a local plastic shop and a few days later I had new ones. Alternatively you can buy a sheet of acrylic and cut your own using wood working tools.

 

[rgranger]

I found this video helpful

 

[FastOlson]

"LifeSeal" will not attack the plastic frames or lenses. I have bedded bare lexan lenses to a cabin side with it and it holds well and never has leaked in over two decades.
The other product mentioned *will* attack plastics.

 

[Mr Fox]

Plus one on Dow 795 silicone (it’s also Don Casey recommended). When I ordered new lexan portlights from my boat’s manufacturer (Marshall Marine), they told me to use phenoseal and my boatyard recommended as an alternative a highly adhesive silicone (like Dow 795). My portlights are Lexan with a bronze frame.

Sikaflex and LifeSeal are both silicone mixed with polyurethane. Polyurethane is attacked by plastic and can cause premature failure of the seal. LifeCaulk is polysulfide which will attack plastic and cloud your portlights.

Marshall Marine, Don Casey and the very knowledgeable staff at my boatyard all agree do not use polyurethane or polysulfide with plastic. Do with that info what you will. I personally took their advice.

FastOlsen had good results with Sikaflex and others I know have too, so I’d say it’s an option. Perhaps when mixed with silicone the polyurethane doesn’t react the same way?

I’ll second the not using butyl tape either- excellent stuff but this (as stated previously) is not the right application.

 

[jssailem]

My portlights are Lexan with a bronze frame.

Is the lexan held in the frame or is the frame just trim around the outside of the Lexan? If the frame presses the Lexan against the side of the boat and is mechanically fastened to the boat then you can place the butyl between the boat deck and the frame sealing the frame from lettign moisture to seep under the frame. Butyl works if the port is mechanically fastened to the boat. If not you need an adhesive caulk like Dow 795.

 

[dlochner]

The conflicting advice in this thread comes from a lack of clarity on the type of port, to which @jssailem alludes.

There are 2 types of port lights, framed and frameless. What works for one type does not necessarily work for the other the other. And one method does not work for either type.

Sealing a port light without removing it by smearing gobs of some kind of sticky goo around the edges doesn't work for very long if at all. Do yourself and the next owner a favor and don't go down that path.

Framed port lights have a metal or plastic frame that is mechanically attached to the cabin sides. Some are through bolted (Beckson Ports), screwed into the cabin side with self-tapping screws (Island Packets?), and others have an Aluminum channel in which the lens sits and with a retaining frame inside the cabin (lots of 1980s boats including Catalina, Sabre, Tanzer). Metal framed mechanically attached ports can be sealed with butyl tape, a combination of butyl tape and a non-silicone caulk. Beckson specifically recommends using a silicone caulk on their plastic framed ports because of concerns about the caulk degrading the plastic frame. For all mechanically fastened ports, the caulk is primarily used to keep water out and only secondarily used to keep the port attached to the boat.

Frameless ports are a different beast. The caulk used on frameless ports hast to keep the water out and keep the lens attached to the boat. Dow 795 and its competitor Silpruf were originally developed as glazing compounds for plate glass windows. While silicone based they are not your hardware store or marine store silicone caulk. These caulks (I've only used Silpruf) are more adhesive, easier to work with, and don't have the same issue with impregnating the fiberglass with silicone that the HW and marine store stuff does. They work well. Rule of thumb, if the silicone caulk smells like vinegar, it is not appropriate for a marine environment.

The video from Boatworks shows how to use 3M Very High Bonding Tape to mount the lenses. This works to keep the lens attached to the boat, however, it still needs some caulk to keep the water out.

If you are considering changing the lens in the port, head over to SelectPlastics.com and read about the different materials, polycarbonate (Lexan), acrylic (plexiglass), and tempered glass.

 

[Mr Fox]

Rule of thumb, if the silicone caulk smells like vinegar, it is not appropriate for a marine environment.

That’s a great tip!

 

[heritage]

I changed out the lens in my Bomar hatch a couple of weeks ago. I ordered the replacement lens, 1/4" plexiglass, from Boatoutfitters.com. I had it in my hands in three days. They cut the corner radiuses perfectly. Very pleased. I used black dow 795 to bed and secure the lens to the cast aluminium frame. If you go with dow 795, make sure the use by date is current. Out of date tubes take forever to dry,, if at all.