Featured Project: Door Latch Upgrade

If you are installing latches for the first time, or upgrading the ones you have, plan to spend a little extra time weighing and measuring what you will need.

There is a lot more to consider than you may initially realize.

I was upgrading an old, worn out Attwood latch that, outside of the handle itself, was mostly plastic.

Its replacement was a fully stainless steel latch that was not only far better looking, but also more durable and functional.

What I didn’t factor in was the significant weight difference between the two. Luckily, my particular application was a large, heavy gunwale rod locker, so the additional weight of the latch was not noticeable.

However, for smaller hatches or hatches with gas shocks that may be near their tolerances, the weight of the latch may be significant enough to require consideration.

There seemed to be a million options for my particular application, but in reality, that wasn’t the case. It took some help from an expert to discover that there were two distinct functions for latches — some that simply held a hatch or door shut, and some that compressed the closure for a tighter fit. Given my initial goal of eliminating the rattle from my boat, I needed to narrow down my search to compression latches. 

Narrowing down by material and function will help reduce the number of options to consider. Within the “function” category, you will also want to determine if the latch will need to be lockable. The locking mechanism on these latches is relatively simple and, at best, a mild theft deterrent. It is an open secret that the keys for these latches are universal. If you have a key to your latch, you have a key to everyone else’s as well. These locks can be helpful, though, for keeping kids or guests from accessing certain compartments too easily.

The general considerations above will help you narrow down the vast array of seemingly identical latches available to you. To narrow it down to the one or two choices that will actually work for your application, a surprising number of dimensions need to be considered. This was a major point of education for me, and had I not ordered multiple latch models instead of just the one I thought I needed, I would likely still be waiting around for the right latch to come in. Here are the various measurements and dimensions to consider.

While the size of the hatch lid hole seems like a pretty obvious measurement, hole diameter is only one consideration. There is a great deal of variation in the way the hole cutout is configured, and that configuration will determine some critical measurements. 

Does the hole have a recessed lip? This may be a factor for flange thickness and diameter. Is the hole round? This may require some thought into how you will keep the entire latch assembly from twisting out of alignment. How big does your flange need to be vs. the core thickness of the rest of the unit?

Another consideration is the thickness of the hatch lid or door that the latch will go through. These latches have a specific thickness range that limits their use. If the hatch lid or door is too thick, you won’t be able to secure the backing plate, which clamps the latch in place, to the rest of the unit. If the hatch lid or door is too thin, you won’t get a tight enough “clamp” to keep the latch in place. Of the two seemingly similar latches I tried, only one worked for the thickness of my rod locker.

Particularly for recessed fittings, the diameter of the flange should be a major consideration. The flange needs to extend beyond the diameter of the latch hole, but within the recessed area it needs to fit into.

Again, particularly for recessed fittings, the thickness of the flange should be considered. In my case, the walls of the recessed area were raw fiberglass and I had to use a spacer to raise the flange to appear flush with the gelcoat around it. For non-recessed fittings, a thinner flange will ensure that the latch doesn’t stand too proud and become a tripping hazard.

The core of the latch is the portion that fits inside the hole or cutout in the hatch lid or door itself. It is important to ensure that the outer diameter of the latch core is only slightly smaller than the hole it will go into – this keeps the latch from sliding around within the hole and disrupting the orientation of the catch.

The portion of the latch that actually grabs onto the opposing surface is the cam, which is usually a longer metal piece that is mounted onto a threaded shaft connected to the shaft handle. When the latch handle is turned, this threaded shaft moves with it, ultimately turning the cam in the same direction. Turning the cam will either latch or unlatch the hatch lid or door. This cam has to connect to a stationary portion of the hatch or door frame to secure the moveable lid or door when closed. There are two dimensions here to consider.

It is important to measure the distance between the top of the lid (or outside surface for doors) and the location that the cam will lock onto in the hatch or door frame. Each latch will have different lengths of threaded shafts as well as different cam shapes that determine the maximum and minimum range that they can accommodate.

The latch cam will have to extend a certain distance from the center of the hole to the fixed area that it will connect to in order to secure the hatch lid or door. Most latches come with multiple cams that are different shapes and lengths, but these will have a maximum and minimum distance that they can accommodate.

If you’ve managed to order the right latch for your application, the good news is that the installation is fairly simple. There are two steps to the process.

This is fairly straightforward. Simply detach the backing plate from the latch, drop the latch in the hole, and then re-attach the backing plate. Keep in mind that you will first do a dry-fit to complete the second step (aligning the cam), and then pull the latch, apply sealant to the hole, and re-install the latch.

This step is a bit more tedious and may require some modification of your hatch or door frame to ensure the best alignment. With the latch secured in the lid or door, choose the right cam based on the required length and shape for your application. Once selected, the cam will need to be positioned at the right depth, and will need to connect to a solid, strong surface on the door frame or hatch. This may require the installation of a metal or starboard plate for the cam to latch onto. 

Like most boat projects, upgrading your latches takes a little research and planning. Unlike most projects, the hardest part is simply choosing a latch that will fit your specific application. Faced with what appears to be endless options, you will quickly realize that, based on the specific size and dimensions of your application, the field narrows alarmingly quickly down to — at best — a handful that will meet your needs. As simple as latches may seem, taking a moment to call a manufacturer or dealer to talk through your specific application can save you time and aggravation later. The time spent up front to order the right latch is rewarded in the relatively simple installation. The final product, however, can significantly improve the form and function of your boat.