Undermount Sink

Undermount sinks look sleek, clean, and modern, but do they work in a boat?

Undermount sinks are attached to the underside of the counter by tiny dinky little clips. Their attachment is aided by the use of adhesive to help hold it on to the underside of the counters while also sealing out any water that might try to leak through the gap between the counter and the sink.

This is all well and good in a house that doesn’t move much, but a boat is the equivalent of living on a fault line while speeding through time. Every day, the boat will cycle through hundreds of movements, each making the entire boat flex and twist. If the heavy sink is hanging from the underside of the counter, it will soon become separated and disconnected from the underside and could possibly just fall off!

So, how do you do it? How do you undermount a sink in a boat? Easy! You top mount the sink beneath the counter!

Under this pretty mahogany butcher block lives an ugly sheet of plywood with a hole cut in it to hold the sink. The sink is simply dropped into this hole and firmly attached to it as a regular drop-in sink. There is no way the sink could possibly fall since it is sitting onto of a sheet of plywood! The pretty counter is then mounted over the sink and firmly fastened into place and the appropriate caulking performed to keep out any leaks.

In a boat, undermounted sinks are better thought of as “sandwich mounted” sinks, where the sink is sandwiched between a plywood sub-counter and the visible counter.

Galley Refit: Polishing Hardwood

All the glue sanded off and the entire counter fit in place. The plastic has been removed and everything is looking ready to go!

Before the wood can be finished, the wood first needs to be prepared! I initially sanded the wood with 60 grit paper to take off the glue lines and fair up any imperfections. Then I graduated to 320 grit paper, then 500 grit paper.

At 500, the wood felt smooth and looked great, but I knew I could do better! To take it the extra mile, I sanded the entire counter with 2000 grit paper, the same kind you use to polish porcelain.

The result was wood that not only felt smooth, but also looked smooth too. Being a very hard wood, the wood itself could be “polished” on it’s own to have an amazing luster where it was “almost” reflective.

With the wood dry and “thirsty” I then caulked the seam between the sink and the counter top. Once that was cured, the counter itself was oiled with linseed oil.

Managing Glue Lines in Corners

The four pieces are assembled and the excess glue has been sanded away. Now we need to glue the four pieces together, but how do you avoid glue lines in the corners where you can’t sand later?

Plastic will keep the boards from gluing to the sink, but how do you keep the glue out of the edges? Masking tape.

Blue masking tape can be placed right up to the edge of the wood joint, then cut off with a sharp knife.

Cutting it instead of tearing it ensures that the edge of the tape is flush up against the edge of the wood with no gap.

The goal is to completely replace the wood in the corner with tape, that way any glue that squeezes out of the joint in the gluing process finds its way onto the tape and not onto the wood.

With the first piece done, it is time to repeat the steps on the next piece of the corner.

If you are lucky and the tape meets the edge of the wood perfectly, you are finished!

If the tape is not perfect, you will need to cut a scribe line into the tape so that it can be peeled off.

Use the tip of a sharp knife to cut the tape on the wood. Don’t worry about scratching the wood as this mark will be in the very corner of the wood, so it won’t show.

With the line marked, simply peel off the excess and be presented with your own custom cut masking tape line.

The tape peels off easy with the tape cut all the way down to the wood with a sharp knife.

Now yo u have the corner protected to perfection. The last step is to fill the wood joint with wood glue and compress the joint with formidable clamping pressure!

Once the wood is clamped up, the excess wood glue will squeeze out. Take a paper towel and wipe up the excess wood glue. Once it is all wiped up, simply peel off the tape and be finished with it. You want to pull the tape off while the glue is still wet or the tape itself will get glued to the wood by the glue, giving you a whole new level of frustration!

The glue that squeezes out on the top of the furniture doesn’t matter because it can easily be sanded off. The glue in the corner is the troublesome part and having tape there will make your life easier.

Galley Refit: Countertops Part 2

Time is short, let’s get gluing!

With the sink set in the area and the mahogany dry fitted onto the counter, everything was measured and fitted. Now it is time to glue up the four independent parts in place, but without getting glue on any of the galley components.

Like the old commercials used to say: “Plastics make it possible!” I cut open a large black trash bag and covered the sink with it, as well as the entire area that will live under the counter. Then the four independent pieces of the counter were isolated from each other with shrink wrap. Having everything in place makes the gluing process easier since I can assemble the whole counter top and just clamp the edge to the bulkhead, applying even pressure to the entire structure.

Titebond III was used to give a permanent and waterproof bond between the planks.

The pieces were allowed to cure overnight and then all the clamps and plastic could be removed from between them.

The inboard edge needed to have a rabbet cut into it to fit onto the edge of the counter’s plywood sheathing. The issue is I didn’t bring my rabbet plane to the Azores, so I had to use a table saw and carefully cut out the section of wood that needed to disappear in order to get it to fit flush up against the edge.

With the four pieces glued into solid pieces and everything test fitted, the next step is to glue the whole counter together, just like before but without the shrink wrap isolating the four pieces of wood.

Galley Refit: Countertops Part 1

Unlike the head, which had a nebulous plan of fiberglass and wood construction, the galley is much more straight forward. The counter top is going to be made out of edge grain sapele mahogany, the plan is completely thought out, and there is a much shorter amount of time available for the project.

Let’s get started!

I had previously ordered all the mahogany that I needed before I even started the head refit. Having a stack of lumber in a boat is always fun! The wood sat in the galley area waiting for me to get around to working with it for months.

The planks that run the length of the galley are simple and straight forward. The pieces that sit at the ends of the sink are a different story. There were the really small blocks and the longer blocks. It was easy to think of the wooden sections as four independent areas: the forward piece, the aft piece, the inboard piece, and the outboard piece.

With a chop saw, we were able to quickly make all the blocks uniform in size and fit nicely into the space available. With all the wood ready and organized, the next step was for Maddie to organize the grain patterns and wood colors into a pattern she found appeasing to the eye. The blocks were then marked and oriented so that we could glue each of the four groups up independently.