Are Hatch Gutters Really Necesary?

[mshugg]

I'm looking ahead in my rebuild project and contemplating three in sole hatches.  I'm in awe of some of the work that some of you have done, particularly the mold making that you've applied to the construction of hatches.

Even so, I wonder if hatches with gutters are significantly dryer than a hatch made of the cut out section of deck with a lip glassed underneath.  I'm sure that I could do the mold, but it would take significantly less time to do the lip.

What are your thoughts?

[love2fish]

I think the gutters serve 2 purposes- 1, to help keep water out of the compartment, obviously this is dependent on properly sized and placed drains or run-off troughs (like on the forward casting deck of the osprey models). But I think the gutters also add strength to the opening. the "walls" of the gutters give you the horizontal rigidity that prevents that area from sagging- something a single "backer" board would not provide. I made a similar hatch for the shelf on my console and while it's strong enough to stack some bags or random stuff on- I would never consider standing on it. even with reinforced fiberglass- it would still eventually weaken and need repaired.

[CLM65]

What Chris said about the added strength is true - kind of like a corrugated panel versus a flat panel.  The flat panel is definitely more flexible than the panel that has "ribs".  However, I think you can use the lip approach if (1) your hatch is not too large, and (2) you make the lip beefy enough. 

I am using both approaches on my flatback project.  I used the lip method for the bilge hatch and the gas tank hatch.  Both of these are relatively small (the longest edge is maybe 18 or 20"), so I don't think there will be more than one person standing on them at one time.  For the storage hatch on my casting deck I used the gutter approach.  This hatch is around 4' long.  Plus I want to keep the contents in the front storage area relatively dry.  As Chris said, I can plumb a drain from the gutter to a convenient discharge point (i.e., onto my main deck).  Since the other two hatches on my main deck are lower, if I had installed gutters, I really couldn't direct the water anywhere other than the bilge anyway, unless I wanted to add another thru hull to the outside (which I didn't want to do).

One other thing...I made my "lip" receivers as "drop-in" assemblies.  I know many have successfully gone the route of glassing the lip to the underside of the deck, but I much prefer to have the joint in compression rather than tension.  That way I'm not relying on the mechanical bond to hold up the weight.  Here's a couple pictures of how I did mine.

[mshugg]

Chris, 

You make a good point.

Craig

What an elegant solution.  I like your hatches, and your mould looks easier to lay up than one with gutters. 

My boat is a CCP, so all of my hatches would be in the cockpit sole, one in front of the coffin box, one bilge access and one baitwell.  The only place my gutters would drain is into the bilge.

Thanks,

Michael

[CLM65]

and your mould looks easier to lay up than one with gutters. 

Yes, much easier.  My first attempts at gutters failed miserably.  Getting the glass to conform to all the changes in direction can be a real challenge.  I have gotten better at it with tips from other members, but the way these were made was a piece of cake.