A leak developed around one of the skylights on my 35.5 AGAIN ! I think it would be a major job pulling the skylight out entirely and was wondering if anyone had any success with recaulking. My thinking is to dig out as much of the old caulking as possible and recaulk with DOW 739 adhesive sealant recommended by Hunter. Anyone have any experience with this? Its a shame Hunter never put a flat batten type moulding around the plexiglas over top of the caulked seam. That may have worked. Anyone know of an after market moulding that will work? I was told the plexiglas works a little and expands and contracts which is the source of the problem causing leakage.The screws don't help either, but another 35.5 owner told me he added more screws every 8 inches around the skylight perimeter. Any recommedations? What about making exterior covers for the skylights like on power boats? although I guess water would run down the cabin top under the cover rendering the cover useless. Fred Miller S/V M Squared
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Not a difficult job!
Fred: I was helping a fellow sailor do exactly this procedure this weekend. This is an easly job. Contact Hunter and get their video on doing this procedure. 1. First you cut out the caulking on the exterior. Then cut around the interior edge. 2. Make a cover on the interior of the boat to keep all of the old caulking from getting all over the interior of the boat. If you just tape some newpaper to the ceiling where the interior lens goes, this should be fine. 3.Get some heavy fishing line and feed it from the exterior to the interior. Have someone down below to help you use the fishing line to CUT the caulking away from the skylight. 4. Completely clean the skylight and the indentation in the cabin. We used putty kniefs, scrapers or a tile tool to get all the old caulking off. 5. Touch up the gel coat with a little acetone. This will helf remove any moisture and clean the entire cavity. 6. Mask off the entire skylight with masking tape (inside & outside). Mask off the deck area. Mask around the interior opening too. 7. Apply a good volume of the caulking to the ledge where the skylight sits. 8. Place the skylight in place. Place screws in holes and screw down just so the caulking starts to oozzee out. 9. Caulk around the edge and tidy up the finish. Let sit until the next day and then secure the screws in place. 10. Strip off your tape and clean up around the area. Herman should be posting a Photo Forum story on this in the next week or so.
Fred: I was helping a fellow sailor do exactly this procedure this weekend. This is an easly job. Contact Hunter and get their video on doing this procedure. 1. First you cut out the caulking on the exterior. Then cut around the interior edge. 2. Make a cover on the interior of the boat to keep all of the old caulking from getting all over the interior of the boat. If you just tape some newpaper to the ceiling where the interior lens goes, this should be fine. 3.Get some heavy fishing line and feed it from the exterior to the interior. Have someone down below to help you use the fishing line to CUT the caulking away from the skylight. 4. Completely clean the skylight and the indentation in the cabin. We used putty kniefs, scrapers or a tile tool to get all the old caulking off. 5. Touch up the gel coat with a little acetone. This will helf remove any moisture and clean the entire cavity. 6. Mask off the entire skylight with masking tape (inside & outside). Mask off the deck area. Mask around the interior opening too. 7. Apply a good volume of the caulking to the ledge where the skylight sits. 8. Place the skylight in place. Place screws in holes and screw down just so the caulking starts to oozzee out. 9. Caulk around the edge and tidy up the finish. Let sit until the next day and then secure the screws in place. 10. Strip off your tape and clean up around the area. Herman should be posting a Photo Forum story on this in the next week or so.
Screws?
Never looked real close on the 35.5 but I don't remember seeing screws, but then their plexiglass is dark and they probably wouldn't pop out at me. Interesting.
Never looked real close on the 35.5 but I don't remember seeing screws, but then their plexiglass is dark and they probably wouldn't pop out at me. Interesting.
about 8 or 10
John: I suppose that different years may be different but Hemans skylights have about 8-10 screws each. I can see this as a pro/con situation. If you don't have the screws, there is no way to pull the skylight down to get a good seal. On the other hand, a screw hole is a good place to get a leak.
John: I suppose that different years may be different but Hemans skylights have about 8-10 screws each. I can see this as a pro/con situation. If you don't have the screws, there is no way to pull the skylight down to get a good seal. On the other hand, a screw hole is a good place to get a leak.
35 or 35.5
Ours is a H-35 of the approx '86 to '88 or '89 vintage and we have screws in milk-white Lexan. The 35.5 came with smoke Lexan or Plexiglass and as I recall they didn't have screws - but could be mistaken. If they had screws they probably blended in with the dark color where as on mine they are quite obvious. Based on chasing leaks on mine, many if not most of the leaks came from the screws. Drill the holes out larger (yup!) to get more contact between the screw shank and the side of the Lexan. The original holes didn't allow for any clearance and consequently there is no way to put sealant in between hence the leak. This goes counter to common sense. Believe it or not, more clearance is actually better. Then there is also the edge joint detail to change using baker rod and bumb-ons. Fixed my skylights several years ago now (5 or ?) after doing battle with them for many years and they've only required one vist since for two screws and the the couple drips were so minor they never made it into the cabin. Never even leaked on my Alaska trip and you're talking major precip there. Can even pressure wash them! There's nothing like a DRY boat!
Ours is a H-35 of the approx '86 to '88 or '89 vintage and we have screws in milk-white Lexan. The 35.5 came with smoke Lexan or Plexiglass and as I recall they didn't have screws - but could be mistaken. If they had screws they probably blended in with the dark color where as on mine they are quite obvious. Based on chasing leaks on mine, many if not most of the leaks came from the screws. Drill the holes out larger (yup!) to get more contact between the screw shank and the side of the Lexan. The original holes didn't allow for any clearance and consequently there is no way to put sealant in between hence the leak. This goes counter to common sense. Believe it or not, more clearance is actually better. Then there is also the edge joint detail to change using baker rod and bumb-ons. Fixed my skylights several years ago now (5 or ?) after doing battle with them for many years and they've only required one vist since for two screws and the the couple drips were so minor they never made it into the cabin. Never even leaked on my Alaska trip and you're talking major precip there. Can even pressure wash them! There's nothing like a DRY boat!
Maybe Another Idea
Steve; sounds like you have the correct methodology for removing and recaulking the skylight. Thanks. I'll keep the instructions handy. I checked with Hunter and learned yet a little more about fixing the problem. 1- Before removing the entire skylight [as the last resort] they suggest digging out as much of the old caulking as possible from the topside. Clean it out real well then recaulk with DOW 739 plastic adhesive sealant which is the stuff Hunter recommends and coincidently sells. Nothing else they say will work as well. Of course, tape around the edges as not to make a mess. Before the stuff cures though, remove the tape or any residual sealant on the tape where it may have touched the bead of caulk will bond it. 2- If that doesn't work, removal of the skylight is necessary as you describe.One thing I was cautioned about was making sure the old skylight if it is to be reused has had the edges sanded clean or a good bond cannot be acheived. All the old caulking must be removed too. It is my thinking that if I have to remove the old skylights I would just as soon replace them with new pieces. Hunter I am told still has the patterns and can fabricate new pieces. Interestingly Hunter says not to re-screw the skylights in place permanantly. Instead after the caulking has skinned over remove the screws and fill in the screw holes, a procedure they do on new boats. Apparently the screws cause the plexi to deform somewhat if it is stepped on or over time, breaking the caulking seal. Sounds logical to me. Lastly is the question of when to do this job. In the interim I'd like to find some tape to cover the seam on the exterior so it can't leak over the winter [I pulled the boat this week]. I don't want to use duct tape as it leaves a residue that is hard to get off. Maybe rigging tape is the answer as it pulls off clean and is certainly weather resistant? Anyone have any experience with this application? Thanks to all, Fred Miller s/v M Squared
Steve; sounds like you have the correct methodology for removing and recaulking the skylight. Thanks. I'll keep the instructions handy. I checked with Hunter and learned yet a little more about fixing the problem. 1- Before removing the entire skylight [as the last resort] they suggest digging out as much of the old caulking as possible from the topside. Clean it out real well then recaulk with DOW 739 plastic adhesive sealant which is the stuff Hunter recommends and coincidently sells. Nothing else they say will work as well. Of course, tape around the edges as not to make a mess. Before the stuff cures though, remove the tape or any residual sealant on the tape where it may have touched the bead of caulk will bond it. 2- If that doesn't work, removal of the skylight is necessary as you describe.One thing I was cautioned about was making sure the old skylight if it is to be reused has had the edges sanded clean or a good bond cannot be acheived. All the old caulking must be removed too. It is my thinking that if I have to remove the old skylights I would just as soon replace them with new pieces. Hunter I am told still has the patterns and can fabricate new pieces. Interestingly Hunter says not to re-screw the skylights in place permanantly. Instead after the caulking has skinned over remove the screws and fill in the screw holes, a procedure they do on new boats. Apparently the screws cause the plexi to deform somewhat if it is stepped on or over time, breaking the caulking seal. Sounds logical to me. Lastly is the question of when to do this job. In the interim I'd like to find some tape to cover the seam on the exterior so it can't leak over the winter [I pulled the boat this week]. I don't want to use duct tape as it leaves a residue that is hard to get off. Maybe rigging tape is the answer as it pulls off clean and is certainly weather resistant? Anyone have any experience with this application? Thanks to all, Fred Miller s/v M Squared
H35 Skylites
Fred and All, "Reset" my H35 skylites last spring and have what I consider a good, no leak "set". Used the Dow Corning 739RTV plastic adhesive sealant (comes in a green tube) and it works great with out the screws. I don't think Dow Chemical makes a 739 sealant. Do not use DC795 silicone building sealant. DC795 was a past (circa 1999) recommendation of the Hunter factory - they have since switched to DC739 as it is a much better adhesive (sealant) for sail boat needs. To my way of thinking the screws are a no no. The secret gentlemen to a good set is to use the Dow Corning solvent OS2. This is a special blend (spray can) for lexan and and really works great in the preparation of plastic, gelcoat and metal surfaces to receive the DC739 sealant. I would not attmept a reseat again without the OS2 to prepare and clean up the area before DC739 adhesive is applied. I have no problem in saying that the task should not even be attempted without OS2 solvent. It is a must, a must. OS2 is an "enabler". It prepares the surface(s) so the DC739 will "stick" adhere to the surface(s). Also, think of the sealant application as forming a big rubber band around the edges of the lexan lens as it sits in the molded opening. I did not use any sealant on the 2" wide lip that forms the base of the opening. This is an overkill and in actual practice defeats the effectiveness of the "rubber band" concept. I did not apply any sealant to the opening before I positioned the lens in the opening. I made sure the lense set down cleanly on the lip. I have use both black and white DC739 sealant. I did not use any masking tape as it was easy to trim the sealant and to clean up the edges with the OS2 solvent. I made sure the lens was center in the openting with spacers along the sides and ends to keep the it centered as the sealant is applied. Without spacers the sealant will cause the lens to "move around" as the DC739 compound flows into the "crack" ie. the gap betgween the edge of the lexan lens and the moulded opening. I removed the spacers after all of the "cracks" were filled. The spacers came out without any trouble and I just added more sealant as needed to fll their void. After a few hours I used clean water and my finger tip to smooth and form the top surface of the sealant in the crack. I "over applied" DC739 as it is easy to trim after it has set up. In any case, do not use screws unless you want to buy another set of lens. As I recall I did use a big bag of rocks (anchor chain - tool bag, etc.) on each of the lens to hold them in place over nite as the sealant set up. I also used DC739 and OS2 to reset (three times) the lens im my Bomar hatches - (big footed deck crew) {;<}. Again, the must use OS2 was the prime element in the preparation and cleanup in makeing the task a good water tight "set". Seal on - with OS2 and DC739. RD
Fred and All, "Reset" my H35 skylites last spring and have what I consider a good, no leak "set". Used the Dow Corning 739RTV plastic adhesive sealant (comes in a green tube) and it works great with out the screws. I don't think Dow Chemical makes a 739 sealant. Do not use DC795 silicone building sealant. DC795 was a past (circa 1999) recommendation of the Hunter factory - they have since switched to DC739 as it is a much better adhesive (sealant) for sail boat needs. To my way of thinking the screws are a no no. The secret gentlemen to a good set is to use the Dow Corning solvent OS2. This is a special blend (spray can) for lexan and and really works great in the preparation of plastic, gelcoat and metal surfaces to receive the DC739 sealant. I would not attmept a reseat again without the OS2 to prepare and clean up the area before DC739 adhesive is applied. I have no problem in saying that the task should not even be attempted without OS2 solvent. It is a must, a must. OS2 is an "enabler". It prepares the surface(s) so the DC739 will "stick" adhere to the surface(s). Also, think of the sealant application as forming a big rubber band around the edges of the lexan lens as it sits in the molded opening. I did not use any sealant on the 2" wide lip that forms the base of the opening. This is an overkill and in actual practice defeats the effectiveness of the "rubber band" concept. I did not apply any sealant to the opening before I positioned the lens in the opening. I made sure the lense set down cleanly on the lip. I have use both black and white DC739 sealant. I did not use any masking tape as it was easy to trim the sealant and to clean up the edges with the OS2 solvent. I made sure the lens was center in the openting with spacers along the sides and ends to keep the it centered as the sealant is applied. Without spacers the sealant will cause the lens to "move around" as the DC739 compound flows into the "crack" ie. the gap betgween the edge of the lexan lens and the moulded opening. I removed the spacers after all of the "cracks" were filled. The spacers came out without any trouble and I just added more sealant as needed to fll their void. After a few hours I used clean water and my finger tip to smooth and form the top surface of the sealant in the crack. I "over applied" DC739 as it is easy to trim after it has set up. In any case, do not use screws unless you want to buy another set of lens. As I recall I did use a big bag of rocks (anchor chain - tool bag, etc.) on each of the lens to hold them in place over nite as the sealant set up. I also used DC739 and OS2 to reset (three times) the lens im my Bomar hatches - (big footed deck crew) {;<}. Again, the must use OS2 was the prime element in the preparation and cleanup in makeing the task a good water tight "set". Seal on - with OS2 and DC739. RD
OS2 Solvent
The OS2 solvent is a Dow Corning product and is available from the same source as the DC739 adhesive. Cost is about $7.oo per can RD
The OS2 solvent is a Dow Corning product and is available from the same source as the DC739 adhesive. Cost is about $7.oo per can RD
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