This is the end of the road for this project.
I have spent 67 hours all inclusive i.e. making handles and fabricating nails.
I sanded the chest down to grit 120 which is the finest grade we have onboard (emery cloth). I had dismounted the handles before doing this, so I didn't have to work around them.
I waited about 2 hours after the sanding, to let the dust settle before applying the finish.
The finish that I have used is "clear urethane electrical isolation" I am pretty sure that it is normal urethane varnish inside a green aerosol can.
The wood absorbed the first and second coat rather fast. I waited approximately 30 minutes between each coat. Then I waited about one hour and lightly touched the surface with a schotch brite pad. Wiped it lightly with some paper and gave it a final 3rd coat.
In an ideal world, I would have waited longer between the coats, and also given it some more coats, but since I am signing of Tuesday, I had to finish the chest.
Once I determined that the 3rd coat was dry enough, I remounted the handles and carefully moved the chest out of the workshop and into a corner of the engine room where it would be out of the way and maybe drying a bit faster.
You never know if someone has got to use the workshop during the night, so I could not just leave it on the table.
Enough talk. Here are the pictures of the finished sea chest.