Radar mount on isomat mast - adapter really needed?

Apr 24, 2006
868
Aloha 32 Toronto, Lake Ontario
Both the Scanstrut and Seadog mast radar mounts recommend an adapter (costing half as much as the mount) for use on Isomat spars. The reason seems to be the integrated spinnaker pole track. I'm assuming the mounts need to be placed further back so the rivets can protrude i nsude the mast for proper installation?

But, I was not planning on using rivets (I don't have access to the heavy-duty gun needed for SS rivets). I plan to drill and tap and use fine thread screws - as I have seen many people do.

So if I am drilling and tapping, would there still be an issue with the integrated track? Looking at the mast cross-section, there would be greater aluminum thickness where the front bolts attach. It would just be a matter of a deeper hole and longer screws.

Curious if anyone has bolted their mount to an Isomat spar? I hate to spend 50% more on an adapter if it's only required for using rivets. But if there is a legitimate reason, I have no issue "doing it right".

Thanks,

Chris
 
Feb 11, 2017
34
I usually hate cheap tools. but did buy an oversized rivet gun at Harbor Freight for very short money and works surprisingly well using for a similar need as you
 
Apr 24, 2006
868
Aloha 32 Toronto, Lake Ontario
True, but if I use rivets I also have to factor in a $200 adapter. Hoping screws will work out.
 
May 7, 2012
1,338
Hunter e33 Maple Bay, BC
But, I was not planning on using rivets (I don't have access to the heavy-duty gun needed for SS rivets).
If you decide to go this route, find a friend with a heavy duty/commercial rivet gun or better yet rent one at about $30-$50 for the day.
 
Sep 11, 2015
147
Hunter 31 Marina del Rey
You need the adapter. I tried it without the adapter and it was a waste of time. Buy it, install it and stop thinking about it :)..
 
Jul 1, 2010
962
Catalina 350 Lake Huron
Rivets will work better than screws for attaching anything to a mast. Get monel rivets instead of stainless. They are stronger and will compress pretty easily with a standard rivet gun (stainless will not).
 
Apr 24, 2006
868
Aloha 32 Toronto, Lake Ontario
You need the adapter. I tried it without the adapter and it was a waste of time. Buy it, install it and stop thinking about it :)..
Perfect. This was exactly the response I was looking for.
Not what I was hoping for, but what I was looking for lol.
Now to find a buddy with a heavy duty rivet gun...