How to attach a Spinnaker Mast Band to the mast

[zeseb]

I have this;
https://www.whitworths.com.au/ronsta...t-band-71-85mm

and I have a whisker pole.

When I bought my boat (40 years old), the mast band was partly detached from the mast. Screws were used to attach it to the mast but the alumium from the mast got corroded with the time.

I am wondering if monel rivets would be a good fit? Is there a lot of forces applied from the genoa when using the whisker pole?

[psk125]

Sheet metal screws might work, but as you note, they can corrode. Rivets might provide more holding power. Try holding the end of the pole yourself some time to find out about the forces involved.

[Jim Cate]

what size boat and how big is the sail to be poled out?

That fitting looks pretty small to me, but I'm used to boats upwards of 36 LOA and big genoas and kites. The axial pole loads can get pretty big, especially if you use the pole canted forward whilst reaching.

Using monel rivets of the same diameter recommended for screws will likely require a pneumatic rivet gun (1/4" or 6 mm?) to set, but will be quite strong.

Jim

[zeseb]

Originally Posted by Jim Cate

what size boat and how big is the sail to be poled out?

That fitting looks pretty small to me, but I'm used to boats upwards of 36 LOA and big genoas and kites. The axial pole loads can get pretty big, especially if you use the pole canted forward whilst reaching.

Using monel rivets of the same diameter recommended for screws will likely require a pneumatic rivet gun (1/4" or 6 mm?) to set, but will be quite strong.

Jim

It's 40 foot boat so there is some forces. I believed that the forces where more on the sheet of the genoa rather than on the base holding the whisker pole. I have no idea, I've never used it to be honest.

My mate has the appropriate rivet gun indeed, like an accordion one.

The hole on this are 6.5mm. What diameter for the rivets shall I choose?

[Bean Counter]

I would use 1/4" (6.5mm) monel or stainless rivets and coat with Tefgel. A thin plastic spacer between the plate and the mast too. If you screw up the rivetting process with an inferior gun, the resulting loose rivet will be a pain to remove and the hole may get too big.

[beetle]

Attach with structural solid rivets stainless steel set in a non-sieze material (I like lanacote). Could also use machine screws tapped into the mast wall - rivets will be stronger.

Do not use hollow rivets.

Place heavy tape inside the stainless fitting where it presses against the mast, this will reduce corrosion between the stainless fitting and the aluminum mast - pipe tape works well, electrical tape will work but is not as thick.

And yes, there is a lot of load applied to that fitting when the genoa is poled out.

If the mast wall is badly corroded from the old screws you may need to drill out the holes to get back to good metal and go up one size in fastener.

- rob