As full-time cruisers with a dog we get on and off our transom into our dingy many times each day. Add to that having friends come and visit by dingy. The result is that you have to pass a line around the stern rail, and everything we have mounted there, to tie the dingy painter off to the stern cleat. So I decided to add two new cleats to either side of the walkthrough to allow for easier, quicker tying off and departing.
I found two, stainless steel cleats that are mounted by bolts or machine screws through the top of the cleat at a discount marine store. From a local hardware store, I picked up some 1/4-inch by two-inch machine screws with a phillips head and an Irwin drill bit and tap set or matching size.
Catalina imbedded an aluminum plate in several locations on the boat for securing hardware to the deck. On the stern, the aluminum plate runs between the two stern rail posts. I chose to install one cleat on each side just next to the stern rail posts closest to the walkthrough.
Once I had the locations marked out, I began drilling the holes. I started using a 1/4-inch drill bit. The drill bit with the tap and drill kit is slightly smaller than 1/4-inch to allow for the tap to cut away material and leave a 1/4-inch threaded hole. Drilling through the fiberglass you can feel the resistance change when you get to the imbedded aluminum plate. I partially drilled into the aluminum plate to create a centering point for the tapping drill bit.
Note on using tools on deck. I learned the hard way to always tie off drills and other tools while working on deck over the water. I use an elastic tie that has a carabiner on one end and a line that secures around the tool on the other. The one I purchased came with 3 ends for going around the tool that clip to the elastic tie. This way I can quickly switch when using multiple tools like a drill and an impact gun.
Once the initial hole is drilled, the next step is to drill the hole to prep for the tap. The Irwin bit was decent quality and cut through aluminum plate quickly. I then cleaned the drilling debris from the area and began the tapping.
For those that haven’t done a lot of tapping, I find that the best process is to slowly advance the tap and after about a half to full turn you begin to feel more resistance. I then back out the tap a half to full turn to clean the cutting blades on the tap. Once the tap is advanced through the plate I will run it all the way out and back in again to make sure the threads are nice and clean.
I prefer to bevel the top of any holes for deck mounted hardware. This allows the bedding material to make a better seal around the bolt. I use a stainless steel counter sink bit to make the bevel.
Once the bevel is complete, I cleaned the entire area and wiped down the fiberglass with acetone. I then prepped the screws by putting them through the cleat and forming butyl tape around the base of the cleat and a cone shape going down the screw. i also coated the bottom half of the screws with Tef-Gel to help protect for corrosion.
Using a cordless impact driver I slowly start the screw. This helps start the screw without cross threading. I took a couple hours to let the butyl tape work in but I was doing this in the Bahamas in 85 degree F temperatures. In colder temps butyl tape will take longer to set properly. I got the screws started and advanced them until the butyl tape starts to squeeze out. Once I see the butyl tape start to squish out I stop and let it sit for 30 minutes. I will then advance it another half to full turn and stop again. I continue doing this until I have advanced the screw all the way down.
The only thing left is to clean up the residual butyl tape and start using the cleat. It makes tying off the dinghy much easier. We have towed the dinghy using these cleats and it tows great. You can keep the dingy directly behind your boat in the flat spot your hull has laid down.