Anchor Locker Drain

rogerbum · Posted: Mon Dec 17, 2012 7:27 pm Post subject:

Do the lower screws on the clamshell penetrate the hull into the space below the anchor locker? Perhaps that's what Dave is talking about.

Sunbeam · Posted: Mon Dec 17, 2012 7:37 pm Post subject:

Sunbeam · Posted: Wed Dec 19, 2012 3:05 pm Post subject:

I took some photos of my 22 Cruiser's anchor locker today, and I think I see what can happen. I wrote explanations right on the photos (which are below in this post), but I'll add additional explanatory text here.

When two fiberglass (or fiberglass-covered) pieces are joined together - say a bulkhead to a hull at a right angle - they are often "tabbed." What this means is that the two surfaces are sanded back for a few inches, and then strips of resin-wetted fiberglass are laminated in place as a joiner. Kind of like "taping" sheet rock, but with fiberglass. After this is done, the two surfaces (fiberglass strip and bulkhead or hull) more-or-less become one, and are usually slightly thicker as a result.

Ideally, the bonds are strong, perfect, continuous primary (chemical) bonds, but in the real world perfection is rare. So sometimes the bond between the "tab" and the hull (or bulkhead are not perfect). There may be a gap or pocket in places.

On the anchor locker, there isn't a liner, per se (at least not on my 2002), but the locker bottom and the partial bulkhead that divides the locker from the v-berth are both tabbed in. This tabbing extends up/forward from the bottom/bulkhead for a few inches, which means that it extends over the area where the anchor-locker drain hole is.

So, if there happens to be an imperfection/gap/air pocket in the tabbing bond that goes from the locker floor to the inside of the hull side (this would not be unusual), and it happens to be right where the drain hole is and extends all the way down, well, you now have a path for water to get below the anchor-locker bottom and under the v-berth flat (which is a liner module).

My original anchor-locker drain hole did not have any gap/imperfection where the hull and tabbing came together, but it was too high to drain the locker well. So I drilled a new, lower hole. This too did not have any really obvious imperfection, but upon close inspection (macro photo), I can see what just might be one. It doesn't look as though it goes deep enough to cause a gap/leak, but just to be sure I will seal it (with epoxy resin and maybe a bit of cloth or maybe just colloidial silica, depending on how it looks when I prep it). It's entirely possible that the drain hole on other boats could happen to hit a bigger gap/imperfection in the tabbing bond.

I was thrown off by the term "liner," as I think of that as being a (typically) gelcoated module that is bonded in to the hull and provides a "finished" inside surface, such as the V-berth flat. So I was looking for something like that in the anchor locker and didn't see it (on my boat anyway). It may exist on other 22's.

Sunbeam Hot

Sunbeam · Posted: Sun Jan 13, 2013 7:48 pm Post subject:

I've finished with the anchor-locker drain hole(s), so I thought I'd post a follow-up. Also, I see that the photos I had in my last post are no longer linked - I organized my album without realizing that would "break" the links to my photos... oops Embarassed

At any rate, they are in my album in a sub-folder called anchor-locker drain if anyone would like to look at them.

So, after I figured out where the potential path was for water to get below the bottom of the anchor locker (through any existing gap between the tabbing and the hull side), I took a close look at both the original and the new holes for draining my anchor locker. I could see where the two different layers existed, but they looked tight and well bonded (that's not to say all the tabbing on my or any boat is like that everywhere, as slight gaps are not unusual; but the area right where the holes were drilled on my boat looked good). Still, the idea of water getting beneath the v-berth was so unappealing that I decided to make doubly sure.

To that end I prepped the holes and coated them with neat epoxy, then added thickened epoxy (colloidial silica), and shaped it for a smooth transition. I had originally planned to fill the upper (original) hole with thickened epoxy, but since it's also going to be hidden by the clamshell I decided that more drainage couldn't hurt. It could always be filled later if I change my mind. (If there had been an actual crack or gap between the tabbing and the hull side then I might have chosen to reinforce it with cloth as well.)

Here is how the holes look now. I tried to make enough notes to orient you, since by the time I zoomed in enough to really show it, there were not many orienting features left in the photo. Note that the new hole is still ever so slightly above the locker bottom; this is because on the outside I wanted to keep the clamshell solidly on a strake vs. partially hanging over a strake line.

Sunbeam

Larry H · Posted: Sun Jan 13, 2013 11:49 pm Post subject:

Excellent diagnosis and repair!

The problems with the anchor locker drain leaking into the under-berth area and the stem band screws leaking was an intermittent one. These problems were most likely caused by inexperienced factory workers. The stem leak was traced to a worker using a drill bit without a stop. The anchor locker drain could have been as Sunbeam says; drilling the hole thru a tab that was not totally bonded.