Beneteau 343 leak from skylight.

CptnRn · Jan 11, 2016

Odd that it would leak after you rebedded it. I'm wondering, is it possible the source of the leak is near by, say the mast base, and water is migrating inside the cabin liner, over to the skylight where it enters the interior? Try putting a little water just on the skylight and see if it leaks thru. If not then you can try a few other locations to see if you can verify the source of the leak.

DougM · Jan 11, 2016

Might not have completely cleaned out the old bedding when doing the repair ....
The surfaces really needed to be clean to get good adhesion.
After that, rule #1 when working around the foredeck: don't stand on the skylights!

BigEasy · Jan 12, 2016

I have posted extensively on the Yahoo Beneteau 343 website as well as posted Beneteau's photo repair procedure in the "files" section of the website. Surprised that you were able to remove the lens entirely without cracking it; the lens cost appx $1500 to replace if it is broken. I removed all of the old caulking from the recessed area around the perimeter of the lens as I didn't want to risk cracking the lens removing it. I sanded the fiberglass surface insdide the recessed area and the edge of the lens as well as cleaned it with acetone to ensure a clean surface.
I used the same stuff that Beneteau uses; 3M P591 primer to prime the fiberglass and lens, then a layer of EMFI Mastic PB polyurethane adhesive/sealer, and finally a layer of GE SilGlazeii SCS 2800 to dress off the recess, flush with the deck. I purchased these products directly from Beneteau So far so good, hasn't leaked in 3 months with all of the rain we have been getting here. One thing that Beneteau advised when removing and rebedding was to make several ( appx 6 to 8) wooden cleats that are screwed into the recess to hold down the lens as the adhesive/sealer sets for 24 hours to ensure that it is bedded thoroughly.

Andres Coronado · Jun 30, 2016

Greetings all, I have a BENETEAU OCEANIS 351 years 1995 and at this moment I am replacing the two windows that do not open located on the deck, I would like know which is the procedure for mounting and materials used for sealing. Beforehand thank you.

Mity · Sep 10, 2018

Good afternoon. I just bought a Beneteau 343 2006 and noticed that the skylight is leaking in the corners. I know that BigEasy posted a reply to this topic in 2016 however I can't find the WEB site mentionned to see the pictures. From BigEasy: 'I have posted extensively on the Yahoo Beneteau 343 website as well as posted Beneteau's photo repair procedure in the "files" section of the website.' Is it possible to have the link for the site and the pictures? I will have to do the same repair in spring.
Thanks

Michel

BigEasy · Sep 10, 2018

Michel,
Just resealed mine AGAIN about 6 weeks ago. Did not remove the lens completely for fear of breaking it. Used Sika flex 295uv (2 tubes), sika cleaner, and primers 206g+p and 209d. Total cost about $160. And about 10 hours personal labor. Been getting lots of rain this summer and repair is holding up well. Note that some are using Dow 795; less expensive because primers aren’t necessary. Will try to locate Beneteau procedure for you; however, that didn’t work too well for me....lasted around 2 years.

BigEasy · Sep 10, 2018

Michel,
I attempted to attach the Beneteau procedure for replacing or rebedding the deck skylight; however, the file was too large. Obviously the critical item is removing the lens without cracking it. As I mentioned in previous postings, I didn't risk removing the lens; I cleaned out all of the old sealer and prepped the channel between the lens and deck. Cleaned, primed, and resealed.
Send me a private message with your email address and I will try to forward the file to you.

BigEasy · Sep 10, 2018

Michel,
I just downloaded the file to the "Downloads" area of the Beneteau Owner's section.
Here's the search protocol:
1. Beneteau Onwer's Forum
2. Boat Info
3. Owner's Resources
4. General Downloads
5. Beneteau Field Guide for Window Replacement

Hope this helps. Any questions, PM me and I will be happy to discuss further.

Mity · Sep 10, 2018

Thanks a lot. I will look at the information and probably do what you did. I do not want to break that glass. I will PM you for more info later

Thanks again

M

Cest La Vie · Sep 11, 2018

There has been extensive discussion of the problem with the 3 series Beneteaus on the 393 Yahoo forum. Bottom line, there is a consensus of opinion that the design of the overhead skylight is a serious design flaw. While most of us treasure the light that the skylight allows, the frequency of leaks among Beneteau 3 series is indicative of a design issue. While most of us agree that all boats ultimately need repairs to ports and hatches, the frequent and widespread failure of the skylight tends to indicate that this item was poorly designed. While I would certainly not expect Beneteau to implement a broad program of replacing all skylights, it would certainly not be unwarranted to expect Beneteau to provide some assistance to remedy this design flaw. Whether assistance is in the form of materials or reimbursement for labor through approved vendors, some support for this flaw appears justified. For the record, I am an original owner of a 2004 393 and love the boat and the quality of production on almost all elements of my boat, with the exception of the overhead skylight design (OK, another bone to pick with the installation of the Yanmar 4JH3E in the two cabin version that requires one to replace the impeller located on the rear of the engine by braille, but that is another story). There is an effort to open a dialog with Beneteau USA to determine if Beneteau is willing to provide some support to remedy the skylight issue.

Gunni · Sep 11, 2018

I don’t think I have met an owner of any boat with glued-in deck lights who is not dealing with leaks. It is a flawed concept based on dis-similar materials and the lack of a mechanical attachment. In my opinion you simply don’t need that light in that location and you don’t need that much solar inside the boat. Having studied the situation because the B393 was on my short list, my intended solution was to do away with the glazing altogether. Glass it in. By the way the B411 has the same number of opening deck hatches (7), installed in different locations.

If I was the owner of one of these boats I would use the glazing as a pattern to vacuum bag a layup of glass and core-cell, then bond it to the cabin top fiberglass with thickened epoxy, possibly thru-bolting it to the flange. There would be no glazing in that location and it would be strong enough to stand on.

If Beneteau USA wanted to be helpful, they would build the glass insert I describe and sell it as a kit. The B393 is a great boat and it deserves a proper fix for this gimmicky feature.

BigEasy · Sep 12, 2018

Totally agree Gunni. Different materials (frp and acrylic) with different thermal expansion rates, bonded with flexible adhesive/sealant bound to leak at some point. Additionally, add the slight camber to the deck on to which the lens is bedded and you’ve really got a disaster in the making. Can’t attach the lens with fasteners because breakage will occur due to expansion & contraction of the lens. That’s a Good idea to fabricate a deck insert that can be mechanically fastened with a weather a resistant seal, sealant, or epoxy. Same nonskid pattern as the surrounding deck. If additional light or ventilation is desired, low profile Lewmar deck hatches could be incorporated into the FRP insert. Beneteau should make that available. I have spent about $300 in materials and approximately 24 hours labor resealing mine twice in the past couple years. Really aggravating; The leaks develop at the forward corners of the lens because of the curvature of the deck.

Ron20324 · Sep 12, 2018

Gunni said:
I don’t think I have met an owner of any boat with glued-in deck lights who is not dealing with leaks. If Beneteau USA wanted to be helpful, they would build the glass insert I describe and sell it as a kit.

And how old is this boat? Beneteaus are probably not the only line made this way. If they made a fix-it kit, that would almost admitting to a design flaw liability and they'd be sued up the bazoo.

BigEasy · Sep 12, 2018

Ron20324 said:
And how old is this boat? Beneteaus are probably not the only line made this way. If they made a fix-it kit, that would almost admitting to a design flaw liability and they'd be sued up the bazoo.

My 343 was commissioned in January '07. Leaks first started about 2 1/2 years ago. ( There is no walking on the lens that occurs that would contribute to leakage.) First time I used the exact sealants and primers that Beneteau initially used. I didn't remove the lens completely, because others have reported cracking the lens attempting to remove it; however, I did a damned good job removing the old sealant and adhesive from the deck flange and recessed channel between the lens and the deck. Was meticulous with sanding, vacuuming, cleaning, priming, and application of the adhesive & sealant.....lasted 2 years. I just resealed it again approximately two months ago using Sika 295UV and all cleaners & associated primers....we shall see how long this repair lasts; however, I am not overly optimistic.

Mity · Sep 12, 2018

Mine was commissioned in early 2006 and the leak is exactly were mentioned in the tread.

I’ll do the sealing without removing it and see how long it will last!

Styrocket · Sep 17, 2018

I have done several of these, I helped the local charter fleet, and I can be of assistance, if you want help or need advice let me know. I had several windows available for re-use, however one of them was really beat up and needed a new one, it should have been Lexan however the owner was fine with plexiglass-glass, still came out nice..... I also put a short youtube vid together - but not sure if it helps, Glenn

Mechone · Sep 17, 2018

Styrocket said:
I have done several of these, I helped the local charter fleet, and I can be of assistance, if you want help or need advice let me know. I had several windows available for re-use, however one of them was really beat up and needed a new one, it should have been Lexan however the owner was fine with plexiglass-glass, still came out nice..... I also put a short youtube vid together - but not sure if it helps, Glenn

Lexan? I replaced windows on 2 boats and was going to use lexan, however I was told by several plastic company's and on many boat forms to use acrylic instead of lexan (polycarbonate) all thou stronger it is highly prone to scratching and not UV resistance( will turn yellow over time). Google it people have said after 4 months the scratches were so bad they ripped them out and replaced with what their boat came with Acrylic. I used dow 795 and have had no problems, they use it to hold skyscraper windows in or 295uv with the expensive primer was told is what some hatch makers use.

BigEasy · Sep 17, 2018

Skyrocket, your video is impressive. As I mentioned in my previous posts, I didn't remove the lens completely for fear of cracking the lens. In discussions with others who have cracked their lens, it seems that the worst part is debonding the mid section of the lens (visible at around 26 sec. in the video) because that is where the most surface area is bonded. Cleaning out the old sealer without completely rebedding the lens is a compromise that no doubt leads to premature leakage as I experienced. Just out of curiosity, what is the cost of a new acrylic lens excluding labor costs for removal and installation? I think that Beneteau asks about $1,000. for a new lens.