Instead of zinc chromate and top coat, I might suggest that you look for some Polyimide epoxy primer (MIL-P-23377) and use just that. It is a two part primer that is used in the aerospace industry. The F-18 flight controls are painted with this paint and uses no top coat. The paint is manufactured by Courtalds, the same people who make Interlux. By the way, we also use this paint as a barrier coat between stainless steel and aluminum as well as use it as a locking compound on our threaded fasteners in lieu of loctite. I always try to keep just a little of it around the house for those odd repairs.
Just my $.02 (US)worth (or $.20 for military advice).

Speaking of mast steps, my 34 has what appears to be a cast aluminum mast step "box" mounted above the keel that collects water. The box does not have any drainage holes. Has anyone with a similar configuration drilled holes in the box to allow it to drain into the bilge? Good idea/bad idea?
Please advise. Thanks. - Matt Wolford

My 32 has the same aluminum box - didn't make any sense to me to let water collect there so I drilled a 1/2" hole and inserted a 1/2" tube which runs into the bilge. It's been working fine for the past three seasons.
Ivan - Lady of Shallot

My 35 III has the same, with no apparent hole. I thinkt he coment made about the blocks/shims blocking any such hole is a valid one. I can not see how a hole would cause any harm, but I can not see how it would help.
My box is painted, and thus has some protection. I suspect that some touch up paint on any exposed metal, aplied whenever you have the stick out, is a good answer.
Michael - "Indigo" C+C 1987 35 Mark III

I have a cast step box mounted above the keel on my 36. There is a hole on the rear port side of the box which I must unplug periodically. When it's not plugged, it actually drains quite well. If you don't have a hole in the cast step box, I would suggest drilling one.....I don't believe it can do anything but help.
Glenn Gambel - Wind N Spirits - C&C 36

Yes, on our 35 mk 111 we drilled a small hole at the back and inserted either windshield washer hose or the hose from an anti-freeze tester. We plumbed it under the removeable bilge cover by routering a hollow underneath it. (about three inches long) It now drains very nicely into bilge and keeps the step fairly dry. In rainy season it still has some humidity, but not enough to worry about.
Klaus

One caution about painting the mast step is the issue of grounding. For lightning protection you may want our mast grounded to the mast step and to the keel. Painting the mast step may interfere with this.
Jim Stephenson - Mischief

Matt,
I have a 1982 34 and did drill two 3/8 inch holes to allow the water to drain. Step now stays nice and dry.
Fred - C&C 34 WIND

Matt,
My 32 came with a hole already drilled in the mast step. Because the mast step is black, it is hard to see the hole and yes it does get clogged with dirt etc and need cleaning. Take a close look at yours. I think you will find it is already there.
Regards, - Tom Anderson - C&C 32 Nonpareil

I drilled one hole in the mast step box and put a plastic tube to the bilge (about a foot of tube) and it works great until it gets dust and then you have to clear the tube. No more water sitting on the sole floor boards!
GEORGE MCBRIDE - C&C35MKIII "Southern STAR"

I have a '72 35' Mk I. Have removed mast for first time since buying it 2 seasons ago. Seems that the mast step that "holds" mast in position (in bilge area) is dissintegrating... (perhaps process is speeded up because of continual wetness in bilge, but that's another discussion)... there's all this white grainy "stuff" surrounding the step. Previous owner removed it at some point and had it sand blasted, then painted. To look at it now, I wouldn't have known that it had been painted. I plan to remove it from boat next week and would like advise about how to treat it. Sand??? Sandblast??? If it should be repainted, suggestions on what product to use?? You or others have ideas for me?
Kate Mullins - Greenfield, NH - Impulse, '72, 35'-I

Hello Tom and Kate,
We are refurbishing a Landfall 38, and although we don't have a mast step problem because the step is mounted on a fiberglas pedestal out of bilge water corrosion harm's way, we are refinishing the aluminum traveller. We dismounted it from the cabin with no small amount of effort, and gave it to a powder coating company. They recommended sandblasting, coating with an anticorrosion primer, (details from them if you are interested further), and then powder coating the whole thing with a proprietary polyethylene coat. We are doing this for appearance and long range durability. We'll let you know how it comes out.
The cost for doing this 5' traveller and two aluminum pedestals is $150, but maybe it could be done by another company cheaper because this guy didn't have sandblasting capabilities and had to farm it out. Anyhow, that is a thought for your refinishing. If there is a dissimilar metals problem in your case, you might try a mylar or other plastic insulator between the mast and the step (between any dissimilar metals). The Islander 36 I just sold had a chronic problem in that regard due to aluminum mast and carbon steel (imagine!) mast step. Mylar was recommended, but I didn't have the problem and so don't know if it works.
Happy refurbishing. - Harry Hutton - s/v Casablanca