Date: Thu Oct 4, 2001 10:38 pm
Friends, my Seawind II has hatches by Atkins & Holyle, the Canadian company. They leak but not thru the rubber gasket that is between the hinged top and the base. They leak thru the joint made by the hatch and the deck. I could attempt to put a bead of silicone or other caulk around the edges or remove the hatch and rebed the hatch with new sealant. Has anyone ever tackled this job?
Date: Thu Sep 27, 2001 11:38 pm
The importance of using the proper compound in resealing anything that contacts the deck or cabin sides is a key issue.
Generally, a determination of whether or not the two surfaces to be bedded may be subject to flexibility determines the most important decision. In this case any amount of potential movement between an opening-port's fiberglass mating surface and the port itself should almost eliminate the use of silicone. Silicone is a sealant and not an adhesive.
Silicone sealants are manufactured to certain standards. We boaters have a tendency to expect too much from silicone and often choose a household grade by its considerably lower price rather than the compound offered as Marine Silicone. The difference is largely the content of emulsified air bubble content. Marine grade silicone contains a far lower emulsification of bubbles and is far superior to most household grades available. In either case to expect that silicone may by substituted for an adhesive that is capable of joining dissimilar materials often leads to an incorrect choice.
Marine grade silicone works quite well if used to seal the hatch lenses to the hatch frames as well as the frame to the deck. In both cases very little movement between the surfaces can be induced. The coach roof sides are actually quite flexible in the areas where little of no coring material is present to prevent normal flexing. In the case of the opening port frames they are attached in an area where no core is present. In this mounting I seriously recommend a polyurethane compound such as Silkaflex or GE 5200 over silicone or the Boat Life type compounds know commonly as poly-sulfides for the application of re-bedding port frames to the cabin sides. For best results before reinstallation be sure to clean each surface thoroughly with lacquer thinner or alcohol before installation and carefully avoid contact with either surface with any grease or oils, even from you hands and fingers, before applying the sealant/adhesive/adhesive.
If it is the hatch frames you are trying to re-seat then using marine grade silicone works splendidly with the same care used in cleaning the mating surfaces. I do however caution you to carefully inspect the aluminum mating surfaces for even minor amounts of surface pitting. Most aluminum hatches are attached with stainless steel screws and the electrolytic corrosion is slow but steady. Aluminum can become very porous after this typical exposure for some years.
In my boat I have sealed the hatch frames to the deck three times over 10-years to only varied degrees of success. This last time I had the frames glass-beaded and powder coated to seal the obviously micro-pitted aluminum surfaces and bedded them in marine grade silicone. Given the choice I believe that the stainless screws should be replaced with silicon bronze fasteners if you expect long-term relief from electrolysis, however.
Date: Fri Sep 28, 2001 8:00 am
I have had good results when rebedding both hatches and ports 3 years ago with Life Caulk, a polysulfide which stays more flexible than Life Seal. Life Caulk has its own cleaner liquid. The outside rubber joining around the port was lightly cracked on its whole exterior surface, so I rubbed silicon on it and it has looked good since then. Small leaks on the central hatch and on the main stbd port have disappeared.
The silicon bronze suggestion for any screw in contact with aluminum makes good sense, I have not tried it but will search for a good source.
Date: Fri Sep 28, 2001 12:47 pm
We have the same hatches, which by the way are an excellent product. But now to the repair process:
1. Select at least 3 days of dry weather.
2. Remove the top section and store safely.
3. Remove all screws holding the unit to the vessel. May need to heat the bolts.
4. Ours was installed with 5200, so we had to use a torch along with hacksaw blades, we heated the hacksaw blades, which soften the 5200 and sawed carefully to separate the hatch frame from the vessel coach roof.
5. Clean the entire mess up until spotless.
6. Apply a bead of 5200 around the frame base or vessel area and install gently. Use enough 5200 so it will squeeze out just 1/8" as you tighten down the frame to the coach roof.
7. To smooth out the 5200, wet your finger with mineral spirits and work smoothing the 5200, use a cloth to wipe up the excess and change the cloth frequently.
8. Use mineral spirits to clean up and your set for another 20 years.
Date: Fri Sep 28, 2001 11:24 am
Why do you select 5200 after the pain you endured lifting the hatches out? Life Caulk, even more than Life Seal is messy (but so is 5200) but holds well and does not stick as hard by a long shot.With the screws sufficiently long, do you really need such a strong adhesive?
Date: Fri Oct 5, 2001 2:50 pm
Thank you for that complete set of instructions on how to handle the hatch problem. Having removed the same hatch before maybe you can answer some questions I have.
1) The bolts holding the hatch in place I assume have screw heads accessible from the deck. What do these screw into and how do you gain access to nut or what ever they are screwed into?
2) Having taken apart pieces that were held by 5200 in the past, I know how dificult it can be. Has anyone had any experience with fluids that are supposed to break the surface bond of an adhesive?
3. When using the hacksaw blade does the blade go thru or does it butt up against a part of the hatch when being used?
Thank you again for your assistance.
Date: Fri Sep 28, 2001 7:39 pm
The screws go into the fiberglass and likely some wood beneath. They are easy to remove, but then you still have the frame to remove. We took a double (two) blades on a hacksaw and using a torch carefully heated the blades until hot enough to pass through the 5200 and somewhat sawed and pushed our way through between the frame and the gel coat. One must be very careful, one with the torch, one with the hacksaw and patience is a real virtue in this situation. I intentionally kept the direct heat off the frame for fear of breaking it. That's why heating the hacksaw blades. A small pencil flame worked best.
I used 5200 during replacment because that is what Allied used in the original installation. Likely you could use some other compound because many improved products have been developed since. I happen to like the tenacity of 5200 and its workability using mineral sprits for clean up and smoothing out. Even if the screws fell completly out, the frame would remain in place with 5200 and that gives me comfort on those dark rough nights when nothing else does.
Date: Fri Sep 28, 2001 5:22 pm
I'm assuming you "float" the hatch(es) on a 1/8" bed of 5200, ie don't tighten hatch all the way down squeezing out most of the 5200...(I installed a Bomar hatch in the head sole and the mfgr's recommendation was to actually create a gasket effect between the hatch and the mounting surface)...
Date: Sat Oct 6, 2001 12:39 am
I would not want to cure a thick section of epoxy because of the problem you mention. Too much heat and possible cracking when it cures and shrinks. Although epoxy doesn't shrink as much as polyester-styrene would.
If you can mix enough of an inert filler into your epoxy then you may be better off as far as shrinkage goes but then you have the problem of mixing to get a uniform mixture. Whatever you elect to do try it before you apply it. I would make a trial batch first to learn exactly how it will behave before doing to the deck.
You also may want to consider installing a 4" inspection port where the pipe is now. The port can be had with a transparent screw cover and would let light in.
Date: Sat Oct 6, 2001 12:52 am
Thanks for the advice. I would not change the screws to bronze unless I see signficant corrosion when I remove them.