PS Advisor December 2017 Issue

Stopping Deck Hatch Leaks

When I searched the internet for advice on repairing a small leak between the lens and sealant on a 20-year-old Lewmar Ocean 60 hatch, on my 1996 Valiant 42, I was dismayed by the dearth of information. Even the Lewmar site does not provide a schematic of the hatch or a service manual. You can purchase a new gasket but that is not what is leaking. There is no mention of the sealant. Hatchmasters quoted a repair cost 1/2 the price of a new replacement with a greater than four-week turnaround. I would still have to remove and replace the hatch. I will wing it, but thinking that if it came to that, I would definitely not want to replace it with a hatch I could not readily service myself. In my subsequent search I found a reference to a PS July 1, 1994 comparison of Offshore Deck Hatches. I was then dismayed to find that the PS archives stop at year 2000. Fortunately, after some rummaging I found the print version. It was still relevant and useful. In fact as far as I can tell, it is the most recent hatch comparison out there.

Bomar hatches
Photos by Drew Frye (top); Darrell Nicholson

Bomar hatches, named to the “Gear of the Year” list in 1998, remain a favorite among builders.

There are two issue here.

One, it has been over 20 years since you reviewed deck hatches. Please consider an update with ease of maintenance one of your considerations.

Two, I had planned to discarded those old issues of PS thinking that they would always be available in the PS archives. I would encourage you to extend the archive back to the first issue, so that people like me could trade several feet of shelf space, for instant electronic access from our boats or anywhere else we might be. Also these early issues are full of relevant information on equipment found on many fine boats dating from that era.

Bob Rohwer

Voyager, Valiant 42

Annapolis, MDl

We’re glad you find the archives useful. We often find ourselves diving into the past for answers we need today. The 1994 test of offshore deck hatches is now available online (a link will be posted with the online version of this article), and we’ll start posting others that are still relevant.

In addition to the 1994 test report, you’ll find several hatch-related articles online that might be help.

Essential Sailing Gear that Lasts (PS October 2017)

Tech editor Ralph Naranjo lists Bomar hatches among the handful of equipment that sailors can count on for the long haul. Bomar was named among the gear of the year in 1998, so if you were looking for a different brand to replace your existing hatch, we’d check their sizes.

Repairing Leaky Portlights (Inside Practical Sailor blog March 22, 2017)

This blog article focuses on repairing fixed ports and reminds do-it-yourselfers that the sealant failure is often a symptom of a structural issue that is causing flexing at the joint. The recommended sealant is butyl tape, used as a gasket.

PS Advisor: Goo vs. Gaskets (PS December 2012)

This 2012 article suggests several possible adhesive sealants for bedding new hatches, with a big thumbs up for butyl tape (available from Bomar and others). It also suggests sealants to use between the glazing and the hatch frame.

Comments (3)

I ended up having to replace the hatch on my Marieholm 261 this year. I bought a Vetus and had to build up the area the hatch sits in with marine plywood and epoxy to get a flat mating surface with no interference with a raised portion of the area around it. Because I was painting the boat anyhow this was not a big deal but if I weren't doing that it would end up pretty ugly. For those of you wanting to replace the 'glass', I highly recommend butyl tape, especially the tape from Compass Marine. Having rebedded all of my deck hardware with it with zero leaks, and also having used cheaper butyl available on amazon, this tape is worth the asking price.

Posted by: Marcus Ward | December 14, 2017 10:38 AM    Report this comment

I find this post timely. This year I researched hatch replacements for the four custom teak hatches on my 1979 Tayana Vancouver 42 an found them all problematic and not workable because of available sizes plus they are all made to install on an essentially flat cutout surface. I eventually contacted Bomar and found that even their custom hatches are again made for the same type of flat surface...so much for custom. To cut out my present raised hatch bases would create unnecessarily large hatches and create internal finishing challenges. It appears I am limited to teak or a composite materials replacement.

~ ~ _/) ~ ~ MJH

Posted by: MJH | November 21, 2017 12:57 PM    Report this comment

DOW 795 is generally considered the go-to sealant for bonding the lens to the frame. Other silicone sealants have poor adhesive strength, and Sika 295 (often recommended) requires an expensive primer. Skip the primer, or apply it too thinly, and UV coming through the glazing will destroy the bond in about a year (we have confirmed this in other PS testing). Although polyurethane sealants can withstand UV when applied as hardware sealants, the bond area itself must be protected from UV, and glazing presents a tricky case. This is true of all common polyurethanes, including products by Sika, 3M, and Locktite.

Posted by: Drew Frye | November 17, 2017 7:35 PM    Report this comment

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