UV probably takes one of the largest tolls on out boat of any one thing not directly attributable to the owner(s). Those of use who keep our boats at 48° north don’t have to deal with it as much as a lot of other people, but even up here, 25 years of sun take a toll. That being said, the portlights and deadlights on Piko had fought a valiant life but they were getting pretty tired…let alone the the sealant and bedding materials that keep these items water-tight. Here is what the pastic looked like before we replaced them.
The two large hatches were crazed to the point where you could barely see though them, and the smaller hatch in the head had a few cracks in it as well as the crazing. The non-opening deadlights are in the same condition, and while non of the hatches or deadlights leaked, it was time to replace them before heading off shore.
This project is just about the opening hatches, since most of the sealants you use for these don’t like to cure when it is cold, I am going to wait until later in the spring when the weather gets warmer to do the deadlights as I was able to remove the frames from the boat and have the sealant set at my house.
I also considered replacing the hatches as some people end up doing, but these goiot hatches that Wauquiez used are very nice and are worth replacing. Using solid, cast aluminum frames, these are much stronger than then welded hatches you see on so many production boats. Their only real downside in my opinion is there is no way to open them from the outside if you do want to do a spinnaker drop into the forward cabin…
There are a few steps to this job:
- Remove the hatches from the boat
- Remove the old plastic from the hatches
- Get new plastic made that fits
- Clean out the old sealant
- Bed the new plastic in the hatch frames
Like all boat projects, seemingly simple tasks end up causing hours of fun. The goiot hatches use some kind of black plastic for the hinges, and getting the original ones out was not an easy task. I ended up having to find just the right tool to use as a battery ram and large hammer to get these things to budge. It still took almost an hour a piece to get out the two larger hatches, and I broke one of the hinges in the process. Luckily, you can still get parts for these 25 year old ports from http://www.marisafe.com/. I also ordered some new gasket materials and few new knobs to bring these back to as good as new condition.
After the upper frames were removed and plastic was used to cover the large holes in my boat against the elements, I took the hatches home to remove the old lenses. I did try and test the old sealant on the hatches, since I think these are original, and see if I could push out the old plastic, and I was not able to, so the old sealant was still working pretty well. Note: These lenses are only attached to the frame via the bedding, there are no fasteners. To get them out, I took a utility knife and just cut the sealant next to the plastic, and was then able to push out the plastic. I out these aside, to take to the local plastic company to get replacements made.
The sealant used appeared to be pretty typical marine silicon, so I just started to work at pulling out the old material. The large hatches were relatively straight forward since the remaining silicon was thick enough you could get it come off by hand if you were careful. This was still a lot of work and took some time to get rid of all the old material. I then took a scotch-bright pad with acetone to throughly clean the surface of the frame.
The smaller hatch was more troublesome and I ended up using my dremel again to clean out the old material. Using the steel wheel as a tip, I was able to remove and clean that hatch and then did the same acetone prep to it.
At this point I took the old lens to http://www.clearcutplastics.com/ here in Seattle to get replacements made. I highly recommend them. They will take the time to go over that needs to be done – the difference in products etc. There are two main types of plastic you can use for replacement: Acrylic and Polycarbonate. I went with Markalon AR polycarbonate (Lexan is just a brand name for polycarbonate) for the replacements rather than the standard acrylic. Do note though, polycarbonate is stronger than acrylic for a given thickness but part of that is because it is more flexible, so whatever sealant you use, need to keep some flexibility so it won’t develop leaks around where the polycarbonate ‘works’ under load. I used gray Dow 795 for this, which seems to fit the bill for this application. They use this stuff to bed fastener-less windows on sky scrapers, so once it sets (7-14 days at 70 degrees, 50% humidity) it is wicked strong.… You have to be careful about using your normal marine sealants (3M 4200,5200 in particular) since many will attack the types of plastic you use for this purpose.
The other option is to use a multi-step product calls SikaFlex 295, which as a cleaner, primer and sealant. The Dow 795 that I ended up using is not your usual Home Depot variety silicon, so you have to do some searching for it. I ended up find it at http://www.atlassupply.com/ here in Seattle, and was able to get basically whosale prices on it, though you do need to have a minimum order of $25, which is about 4 tubes.
After getting the new lenses made (It took them 4 days from when I dropped them off, but they did have the material in stock) I installed the lenses. All of the sealants used are somewhat messy, so do not be tempted to remove the protective film from the plastic before they are installed. Instead, determine what part of the lens will actually make contact with the frame and just remove the film from that part. That way you don’t have to worry about excess sealant getting on the hatches. I then laid down a large bead of sealant around the frame and pressed the lens into place. You want to make sure that you have good seal on both the bottom and side of the frame to maintain strength, prevent leaks, and to protect the side of the lens from UV. The 795 takes a a few hours to become tack free, so I let the hatches sit overnight. I then removed the excess sealant before it comeplety cures which will happen in 2-3 weeks depending on the temp. I then carefully removed the protective film from both sides of the hatch. Be careful though, the sealant is still sticky where it is thick, so don’t get any one the hatch. Here is a closeup of what the job looks like after it is done.
After carefully making sure I have a good seal all the way around, I just let them sit in the room with a space heater for a few days to get them mostly cured before I installed them on the boat.
Here is a good before and after picture on the boat: