Bottom Paint, Zincs and more

October 22, 2023

If you are reading this post then you must be interested in boring technical detail. I simply post this as logged items, rather than for general prose.

Bottom Paint is a tricky topic I have come to learn. There are lots of different paints to solve lots of problems and knowing a little bit helps, but knowing a lot would be better. Here is the little bit that I learned this year.

  1. I had Micron CSC bottom paint on my boat.
  2. Getting this product in Grenada was very hard. Particularly in black.
  3. The upgraded product, Micron Extra SPC is similar but includes an ‘anti-slime’ agent to improve the paint. Of course it costs more!
  4. There are compatibility charts for every manufacturer showing which paints can be put on top of other paints. I had never seen one before, but now I know.
  5. Home Free was painted with two coats of Interlux Micron Extra SPC on October 20 and 21 of 2023

I have checked all of my zincs and I am desperately in need in just two areas. The first is my shaft /propeller zinc on the main prop and the second is the zincs on the keel cooler (main engine). The keel cooler for the stabilizers is titanium and doesn’t need zincs.

Zincs were ordered from and shipped to Wes’s aggregator in Miami, Florida. It isn’t clear whether they will make it to Grenada before the boat goes in the water, so I have noted what is required to replace the zincs underwater.

  1. Shaft Zinc is an N47PZ ($129), and it is held on with a 9/16 bolt which screws in counter-clockwise and spins out clockwise. To prevent the bolt from coming out there is a metal tab which goes on between the zinc and the head and can then be bent over the head to prevent it spinning off. This bolt would be hard to source, don’t lose it.
9/16 wrench, LEFT TO TIGHTEN, wrap the bolt head with the metal tabs
  1. The keel cooler zincs are almost completely gone. They are 2624A Anode for Fernstrum Keel coolers. The bolts are special bronze bolts and have been acquired as well and should be replaced. They can be taken off with a 3/4″ box wrench.
3/4″ wrench, zinc on both ends of the cooler, use new bolts when possible
  1. The main zincs are B-4 zincs and are currently in good shape but I will replace them. They also use a 3/4″ socket but it must be a socket wrench.

Finally, the replacement of the speed/depth sensor was a hassle because we started out ignoring the instructions. In the end the sensor was replaced (744LV) and installed with the anti-rotation piece and a very clean bolt which can be spun off again to maintain/replace it if necessary.

First try, this didn’t work. The threads were gummed up and we couldn’t spin it on tight or off!

The cable still needs to be run and hopefully we did no damage with the original attempt at the install. The good news is that the sensor should be easier to replace/maintain by a solo boater. The key here was to keep the threads clear of silicone at the top so the nut could be spun on easily. It looks like Wes did a great job of sealing it at the interface to the hull, this is also important so there is no water intrusion.

With the proper anti-spin housing and well sealed hopefully!

On the inside there is not a lot of room to work and tightening the bolt involved a lot of missing skin on my knuckles, and the large nut holding the sensor is a 2 1/2″ nut that we had a special tool built to hold in place due to poor access.

This is the access. It’s really tough to get a wrench on anything and leverage is hard
A custom ‘wrench’ giving enough leverage to remove the gummed up nut.

Leave a Reply

search previous next tag category expand menu location phone mail time cart zoom edit close