How to Replace the Hatches on Your Boat

Match the Hatch

Most parts of your boat don’t improve with age, but few are easier to swap than deck hatches.

Any boat’s hatches perform a few critical functions that are easy to appreciate and very hard to lose. First off, the safety factor of having direct access to the outside from belowdecks is impossible to overstate. A close second is keeping unwanted water out. There’s a reason hatches have dogs and latches to seal them shut. Third and fourth are ventilation and natural light. All these functions contribute to the comfort and well-being of a crew.

But hatches perform still another function: They look good. Unless they don’t. When they stop looking good, because the frame’s finish has dimmed or the lens is hazy or the thing is just beaten up, they can take even the most carefully looked-after boat down a peg on the pretty scale. And those aesthetics count, which is why swapping out your hatches is a worthy weekend venture.

“It’s a really cool project,” says Bob Walker, technical support representative at Vetus (www.vetus.com). “We’ve all seen it. You go aboard somebody’s boat and even if everything else looks good—maybe they’ve even had the brightwork done—and they’ve got a bunch of old hatches? You know, the anodizing is kind of dreary and discolored and, in particular, if the lenses are cracked. Let’s just say new ones can really put the finishing touch on a boat.”

Little did we know how easy it is to replace hatches. We discovered the simplicity of the project first hand when replacing the old, beat-up hatches aboard Arawak. If you haven’t been following along, Arawak is the 1996 Grand Banks 42 Motor Yacht that has been the subject of a repower and extensive refit as part of the MyBoatWorks project (www.betterpowerboat.com).

Hatch replacement is something any moderately handy boater can tackle on his or her own. All you need is the proper replacement hatch, an understanding of how to properly bed on-deck equipment, and the will to improve the look and function of your boat dramatically. “We did four of them in an afternoon,” Walker says. “It wasn’t too hard. If a boater plans ahead properly and orders the right-size hatch it’s pretty straightforward. It’s probably a really good owner project for somebody who wants to get their hands dirty.”

First things first, when planning for this project, you need to figure out which hatches you want to replace. Chances are you will want to do all of them in a section of the deck at once to create a uniform look. Depending on what you have in place already, the replacement hatches you need may be easy to figure out. On Arawak, the hatches were swapped with replacements from Vetus that are designed to match the originals in dimensions, right down to the radius of the corners.

“In a lot of cases there’s no cutting required,” Walker says. “We didn’t even touch the original trim on the boat when we swapped these out. It was kind of a bolt-off, bolt-on. If you know what hatch you have—basically what Vetus did is size the hatches to fit the same overall cutout dimensions and radius corners of some of the more popular hatches.”

On Arawak the four existing deck hatches were replaced with Vetus’s Magnus hatches (starting at $293.75 retail, depending on size), which hold themselves open with friction hinges. Vetus also offers a stay arm add-on that allows the hatch to hold its setting in blustery conditions. The hatches come with a screw that holds the deck frame and hatch together for transportation and storage, and it must be removed before installation. Place the hatch in position and mark the position of the mounting holes. Use the proper screws, whether self-tapping screws for fiberglass decks or steel nuts and bolts on steel decks. Only tighten the screws enough that the sealer is just beginning to be squeezed out. Don’t overtighten.

There are a couple of things to consider when undertaking this project. First, what condition will you find the surrounding deck in before replacing the hatch? If the bedding has failed on the previous hatch, it’s possible that the deck has water intrusion in the coring, which could cause decks that are spongy when you step on them. A surveyor will find this by sounding the deck and finding the trouble spot, then using a moisture meter to get a sense of the intrusion level. But the classic telltale sign is cracking in the gelcoat.

“You’ll notice a lot of localized cracking,” Walker says. “Because what happens is the coring has gotten wet and any time someone steps on the laminate it flexes and cracks. If you’re in an area where there’s cold weather, the water in the coring will expand and contract and cause even more cracking and more damage. If you see spots in the gelcoat where there’s a lot of localized cracking—and I’m not talking about little hairline cracks in the gelcoat radiating from a screw or fastener—you may have a spongy core.” When it comes to hatch replacement, however, water intrusion in coring material is not a dealbreaker. Often, you can put a brand-new hatch in a deck with the thought that you can come back and  fix the deck later on.

Another consideration is how to deal with bedding and sealing materials. If the person who last fitted your boat’s hatches used a permanent sealer such as 3M 5200, you may spend some time cursing his or her name to high heaven, and with good reason.

“If the old hatch was bedded down with some strong adhesive, sometimes it’ll be a little trouble getting the old hatch off,” Walker says with a laugh. “The plus side is you really don’t care if you end up damaging the old hatch getting it off. It’s going in the garbage anyway. But, of course, then you’re kind of committed to put in the new one.” When dealing with 5200, incidentally, the fiberglass remaining under the flanges of the old hatch is not quite so easy to deal with as the hatch itself. To remove residue try products like Anti-Bond (a 4-ounce container sells for $32 at www.westmarine.com) in league with a sharp knife or a razor blade.

Understandably, the team on Arawak opted for a Sikaflex caulk, which seals but not so permanently that it cannot come off easily (something to think about if you’ve got a deck in need of repair).

“I learned a cool way to remove excess caulk after the hatch was installed,” Walker says. “It made cleanup very easy. I’m a big believer in blue tape. So we taped all around, then we scraped off the excess with a paint stirrer, like you’d use to mix epoxy. But before you scrape it you spray it all down with soapy water. The soapy water keeps the caulk from sticking to the frame and the gelcoat where you don’t want it.” And anything that speeds the cleanup and lets you replace four hatches in an afternoon is all right with us.

This article originally appeared in the April 2016 issue of Power & Motoryacht magazine.