One of the most common items on our repair or upgrade list is replacing ports. Crazed glazing, leaking seals and leaks around the edges of the ports are common problems. After years of sailing San Francisco Bay, the ports on my Columbia were in need of replacement. In the process of replacing those ports, I found that there are many different types of replacement ports available.
Materials, Sizes and Installation Considerations
You can pay as little as $70.00 or over $400.00 for a port, Before making the choice of a replacement, you?ll need to consider three things: materials, size and installation.
Frame Materials
Plastic
* Common on many boats
* Durable if properly cared for
* Good selection of sizes and types
Extruded aluminum
* Aluminum is usually marine alloy
* Often anodized for better corrosion protection
Cast aluminum
* Most are powder coated for additional corrosion protection
Bronze
* Traditional look
* Require periodic polishing
Stainless steel
* Considered top of the line
* Durable
* Expensive
* Don?t need polishing
Lens material
There are three type of glazing used in ports, acrylic, polycarbonate and glass.
Acrylics (Plexiglas) have been around for a long time and have proven more than strong enough. It is available in several colors, clear, smoked gray and bronze being the usual ones. The colored glazing helps reduce the amount of UV going below to fade upholstery and dull varnish.
Newer on the scene are polycarbonate lenses (Lexan). This material is stronger than the acrylics, but less scratch resistant. It is also more expensive.
The other glazing material is glass. The glass found in ports today is tempered or tempered and laminated, eliminating any dangers from broken glass shards. It is resistant to common cleaning compounds and solvents, something you have to be careful of with the acrylics and polycarbonate.
Sizes
Most of our boats have rectangular ports in a limited range of sizes. Manufacturers provide drop in replacements for most of these sizes. The most important dimension to look for is the cutout size, the size of the hole in your cabin side. If you cannot find a port that fits your existing opening, you?ll be forced to some major work to enlarge or reduce the size of that opening. Enlarging an opening is easier than reducing one.
Installation Considerations
Some ports are designed for specific angles of the cabin sides to provide proper drainage. Others have a specific range of cabin wall thicknesses in which they can be installed. Some ports are bolted through the trim ring, cabin wall and the port itself. Other port designs have the trim ring holes offset from the port mounting holes. Still other ports are simply glued in place.
After looking at all the options and even purchasing one bronze port, I elected to go with ABI stainless steel ports. These have offset trim ring/port mounting holes and were adaptable to the cabin wall thickness on my boat.
Preparation
Like all projects, replacing ports depends on proper preparation. In most cases, the cabin sides of our boats are of cored construction. The cabin wall consists of an outside layer (or skin) of fiberglass, a center core (plywood in my case) and an interior layer of fiberglass. My leaking ports had allowed water into the core, which, in turn, resulted in rotted and delaminated plywood around the port openings.
The first step was to clean out all the soft, wet wood. I cut back an inch or two around the opening using small routers, Dremel tools, chisels and saws, anything that would get the soggy, wet wood out. I washed out the resulting cavity with some acetone and let it dry.
I filled the empty spaces around the port openings with a mixture of epoxy, colloidal silica and high-density filler. This sealed off the core from any further water intrusion and gave me a solid place for mounting the port.
Port Installation
Since the mounting holes in my ports and trim rings were offset, I was able to use a trick I had developed while replacing the fixed windows on my boat.
Once the locations of all the mounting holes were drilled, I counter-bored the holes and epoxied tee-nuts in place. The outside trim ring mounting holes were counter-bored from the inside and the inside port mounting holes were counter bored from the outside.
This resulted in stainless steel tee-nuts buried in the cabin wall, isolated from the other side and sealed with epoxy. Since no fasteners completely penetrated the cabin wall, there was no place for water to leak through the fastener holes and into the core or cabin.
I taped off the cabin wall and the flanges and edges of the port. Placing the port and the trim ring back in the opening, I traced around each. After removing the port and trim ring, I cut away the tape underneath there where the sealant would go. The better job one does here, the less cleanup there will be.
There was one final step before actually bolting things in place. I put each fastener through its hole in the port or trim ring and then placed a rubber washer on it. The washers are about 3/4? in diameter and about an eighth of an inch thick and can be purchased at most home improvement or hardware stores.
The rubber washers allow you to tighten the fasteners down on the washers and leave a proper thickness of sealant under the port or trim ring. The worst thing you can do when bedding anything in sealant is to tighten down the fasteners too much which squeezes out all the sealant.
With the washers in place, I applied a generous amount of sealant on the mounting surface of the port. I prefer 3M101 or LifeSeal polysulfide caulk. Polyurethanes like 3M5200 are better adhesives, but are difficult to remove when rebedding the port. I used plenty of sealant so I didn?t get any sealant-starved areas. I placed the port in its opening and tightened down the fasteners.
I installed the trim ring the same way I did the port and then cleaned up. There should be a decent amount of sealant squeezing out from under the edges, a sign there are no voids. I cleaned up using tongue depressors with the end cut square. I wiped up the rest of the sealant with paper towels and a bit of solvent for the sealant and then removed the tape.
Properly installed, ports should never leak during the life of the sealant. With an adequate thickness of sealant under the port, the differing expansion rate between the port and cabin wall is easily accommodated. The new ports look great and haven?t leaked a drop in five years!
Capt'n Pauley
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