Hobie Bob Mount

So I took my H18 out this weekend with my dad and we capsized for the first time. It has the older discontinued Hobie Bob mounted on the mast with the standard mounting hardware that came with it (the bob was mounted by the previous owner, but it looks like the hardware that comes with the bob was used), and as soon as it hit the water it broke off by pulling the rivets out of the mast. This left some pretty big holes in the mast, so the boat turtled in about 30 seconds after it went over (and I'm sure my old mast is not sealed very well to begin with). I searched the forum but couldn't find anyone that had a similar problem. I was just wondering if anybody else has found a stronger way to mount the bob to the mast.

I bought a larger hobbie bob and it did not have hardware to mount to the hobie18. I think its for the 16. The internet site I bought it from did not have much of a description including that it was not for a Hobie18.

Anyway. I found some 2" X 2" X 1/8" aluminium angle iron and cut two pieces about 3" long. I rivited them to the top of the masthead- gobbing the rivits with penty of silicon. They were rivited on each side of the pulley hump for the main sail halyard wheel. There are (4) 3/16 rivits in each angle iron. The angle irons then bolt to the 2 bob bracket on the vertical surface of the angle iron. It is held in with 2 sides X4 rivits =8 rivits and 2X2 = 4 #10 stainless screws which bolt the bob bracket to the angle irons. I then added 4 extra rivets between the top cap and the mast to compensate for extra weight.

I don't know if it would break on impact, but it does flex a tiny bit.