Cleat installation 101

Posted: May 1, 2012

Whether it’s new or a replacement, you can install it yourself.

By: Frank Lanier

It’s the absence of a cleat when it’s needed most that makes you fully aware of its value. As a marine surveyor, I see too many cases where builders have skimped on the number of cleats installed, their size or both. Fortunately, such issues can be easily corrected with a little planning and an hour or so of do-it-yourself time. Here are some tips on installing a new cleat or upgrading an existing one.

Solid vs. Cored Decking

Mounting a cleat in solid fiberglass is fairly straightforward; however, drilling into a cored deck requires additional steps to prevent damage to the coring (e.g., water intrusion or crushing). If the coring is plywood, wet the raw edges of the holes with a few coats of epoxy after drilling or cutting. If the coring is a softer material (e.g., balsa or foam), you’ll need to de-core the area.

Using the cleat-mounting holes as a guide, take a 1-inch hole saw (or larger, depending on the size of your backing washers) and remove the coring from the underside of the deck at each bolt hole, being careful not to drill through or damage the upper layer of fiberglass. Drill almost through the coring, but remove the last quarter inch or so by hand (to avoid any chance of damaging the outer fiberglass layer). Another option would be to de-core a rectangular area large enough to cover the mounting footprint of the cleat, and use a one-piece backing plate in lieu of washers.

Once the cutout is removed, seal the exposed edges of the coring with thickened epoxy, and allow it to cure before mounting the cleat.

With the area properly prepared, follow these steps for a successful installation:

1. For new cleats, verify that the location has adequate access and clearance beneath the deck to reach and install mounting hardware.

2. Determine the type of cleat you want (e.g., a traditional “horn” type or a pop-up style). If you’re upgrading a traditional cleat with a larger one, the footprint of the new cleat probably won’t match the existing hole pattern. If the base of the new cleat covers the old holes, you can simply seal them with thickened epoxy — otherwise, the new cleat may need a base (e.g., wood or StarBoard) to cover the holes.

3. Cover the area with masking tape to protect the gelcoat from scratches and prevent chipping while drilling or ­cutting.

4. Use templates (if provided) or the base of the cleat to mark the mounting holes.

5. When drilling, run the drill in reverse until you’re through the gelcoat (to prevent chipping), then switch to forward and continue drilling. Beveling each hole helps prevent future gelcoat cracks and provides a better seal once caulking is applied.

6. Pop-up cleats require an additional hole to be cut in the deck. Most come with a precut backing plate, which makes an excellent drilling and cutting template.

7. Once the holes are drilled, dry fit the cleat prior to mounting (to ensure proper fit) and then bed with suitable marine-grade caulking. Apply caulking to the base of the cleat and top of the backing plate, snug up the mounting hardware until the bedding compound starts to ooze out around the edges and then leave it overnight to set up, forming a gasket. Wait 24 hours, then tighten to the proper torque.

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