Mast step

I have one of the first 18's, sail numbering in the 400's and it has a 2 rivet mast step. Looks like someone used it without the bearing, its worn down to where there is no threaded hole for the bolt to hold the bearing on. I bought a used step and it is the 4 rivet kind.

Question 1.) can I simply drill the 2 extra holes in the cross bar? The 2 others seem to line up.

Question 2.) I was going to do the above but the rivets I bought wouldn't grip. I bought ss rivets 3/16 diameter and they are 5/16-3/8 grip range. I thought those were the size called for? What size do I need to use?

You may not be able to use the origonal size rivets if you are planning on using the origonal rivet holes/location ..... That is an aluminuim casting/crossbar with a Stainless Steel/monel rivet ... two dissimiliar metals ===> electrolisis/galvanic action ===> corrision.

You may need to use a larger size rivets .... I would re-drill the holes ... cleaning out the corrision and install the next larger size rivets availible ...

Or you could re-locate the rivets to new locations ....

Verify that you have one of the "improved" mast bases .... (rivet holes line up???) ... it has a bigger footprint ... and the dolphin striker actually sticks up through the mast mast to provide a post for the mast ball to slide down/over w/ a screw in the top to retain the mast ball in place. I would not use an "origonal" style H18 Mast Base, as the screw can shear off, the mast ball slides off the base and the mast can "kick-out" from the bottom ..... VERY UGLY Dis-masting ... (usually puts holes in tramp ... hulls ...etc, etc .... your basic "very bad day!!!!!" .....)

( I got lucky when it happened to me ... as the mast stayed up after getting caught out in +41knot winds when a front dropped through .... when we de-rigged the mast base/screw/mast ball fell off the boat in pieces ... we were very very lucky ....)

Trick: Take a H16 "Mast Wafer" make a hole in the center large enough so that the wafer will fit onto the new mast base over the post in the middle .... then install the mast ball ... this will provide a "frictionless" surface for the mast ball to spin on .... it greatly extends the life of the mast ball and makes the mast able to "tack/rotate" much easier .... especially in light conditions/high rig tensions .....

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HarryMurphey
H-18 mag/ #9458
Fleet 54 Div 11

What type rivet would I use to prevent corrosion?

If I 'relocate' what do I do about the old holes?

I'm not a "hardware" expert ... the monel rivets are much stronger then aluminum rivets ... and a steel rivet will rust/oxide .... so that is something you may just have to put up w/ as there may not be any solution. I have heard of compounds that prevent corrosion between two different dis-similiar metals ... that are applied between the metals .... I'm just not informed on which compounds are availible ... and should be used in each particuliar case.

Start a new thread here and on "Catsailor" .... I'm sure someone knows the correct "stuff" to use ... ( my grey hairs are effecting my memory cells ... anymore .... )

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HarryMurphey
H-18 mag/ #9458
Fleet 54 Div 11

Monel is better than stainless steel for corrosion prevention. Lanocote is the stuff Harry's trying to think of that prevents corrosion. You can get it at West Marine. It's like a grease.

You should rinse salt water off the boat as often as possible.

The old holes are unsightly, but you really don't need to do anything with them. You can put an aluminum rivet in them to fill them up. I just put a piece of tape over them.