Just bought an old ('83) Hobie 18. The mast step casting was above the forward crossbar. I drilled out the pop rivets and the dolphin striker post pushed up through the crossbar. I need to use my 8:1 mainsheet system to pull down the cross-rod, so as to allow new rivets into the mast base casting. Is this upward stress normal; without a load (mast not stepped)? If not normal, what is the problem?

Cheers & thanks for any help.

I can't speak specifically for the Hobie 18, but it's normal to run pre-tension on the dolphin striker such to pre-bend the beam. I would imagine that you should have some sort of adjustment either on the dolphin striker or mast post to release the tension.

Some tension is normal - however, to mount the mast step you probably want to back off the adjustment, then re-tighten it after the mast step is mounted.

Speaking of mast steps and H-18s - I forget which year this happened, but there is a new style of mast step for the 18 that uses four rivets to attach it to the crossbeam instead of the old two. Much better for avoiding the very problem you are probably fixing - the mast step comes lose from the crossbar. If you're going through the motions, and don't need the boat right away, I'd suggest ordering a new mast step and mounting that. If you do, you will also need a new striker rod. I did this to my old 18, the new step was more solid.

As for the tension needed, opinion probably varies. IMO, you want it tight but no so tight it is obviously deforming the crossbeam. And you expected a precise answer...

The attached pic is off the new style mount.

Agreed. If you don't have the 4-rivet mast step, you should get one.

The dolphin striker rod passes through the front crossbar end castings. It is threaded on each end and is tensioned by adjusting the nuts on the ends. However, if your boat has been sailed in salt water, it is very likely that that the striker rod has frozen to the end caps and even if you loosen the nuts, the rod won't move. If you can't get the rod free, you'll probably have to force the mast mast step down to rivet it in place. I've done this once using the trailer winch to pull the down on the step.

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Agreed. Buy the 4 rivot model mast step. You will probably not be able to loosen the nuts to adjust the tension. You could probably rig something to use your mainsheet blocks tied to the dolphin striker and then tied to a tiedown or the trailer.

Good Luck,
Mike Hill

Been there done that. The new 4 hole for sure. No need to loosen the striker. Have someone stand on it to get it down and drill and install your rivets. Don't forget to use rivet caps to help keep water out and eliminate some corrosion, alum against alum better than stainless against alum. Use stainless rivets with stainless monels for more pulling strenght.The steel monels will rust and stain.

The easiest solution to get the step casting back flush on the crossbar is to use a scissor jack (many car models have them) between the striker rod and crossbar. Right next to the post.

If you want to use the old parts... add two rivets. One on either side.