Mounting of Hobie 18 rear crossbar - tips needed!

Hi! I hope someone on here is more experienced with fixing the Hobie 18 and can help us out...

So, the situation is: our rear crossbar broke, we ordered and received a replacement but have trouble installing it.

We have two questions:

1) Does anyone know how to mount the rear interior casting? We have searched the web and simply cannot find instructions anywhere! Out question is: do you simply screw the inserted bar bolt into the interior casting, or is a nut on top needed? If a nut is needed - how do you screw this on within the crossbar?

2) Is it a problem that the rear crossbar curves significantly - thus putting quite a bit of distance between the crossbar and the hulls when we position it on top? I'll attach a photo (if I can figure out how!) to show what I mean and how much we are talking about. If it is a problem, how do we fix it?

I really hope someone can help us out, we are stuck ashore at the moment and longing to get back out in the water!

Br Alice

1) There is no nut required for the inboard bolts. There are castijgs riveted to the inside of the crossbars and those castings have threaded inserts in them. You simply screw the bolt directly into the crossbar. I highly suggest you try this first with the crossbar off the boat. Make sure that the threads on the screw and inside the casting are clean and the screw threads in smoothly without binding. If it binds, you will need to clean the threads with a 3/8-16 tap. Also be sure to always install the screw with anti-seize grease applied to the threads. Otherwise the screws can gall and bind up.

2) If the rear crossbar is not seating flush, my guess would be that you didn’t loosen the bolts on the forward crossbar first (did you?). It can be quite challenging to get all eight bolts lined up, especially if you tighten some of them before installing others. If the front crossbar is already installed on the boat, I would suggest removing all outboard bolts entirely and significantly loosening the inboard bolts first. This will allow the hulls to wiggle around to line up with the rear crossbar. Have one person hold the crossbar above the hull while the other person gets the inboard bolts started, then lower the crossbar down onto the hull and tighten the bolts until they are just snug. Then install all outboard bolts and snug them up. Then go back and re-tighten the inboard bolts. Continue going back and forth until all bolts are tight. It also helps a lot to use an extended reach hex bit socket which allows you to install the inboard bolts using a ratchet wrench instead of the typical L shaped allen wrench.

sm

The above comment is correct. Loosen the front beam bolts first.
Make sure the boat is sitting on very flat ground. Any undulation in the ground will be not helping.

I have done front and rear beam restorations. Look at my boats Facebook page (link below) and go to the beam restoration photo album.

Before fitting the beams I highly recommend:
- uninstall the internal castings and paint them. These corrode a massive amount over time and this creates unseen issues both inside the beam and under the beam.
- remove the internal casting rivets and replace them with 6mm stainless steel bolts tapped and threaded into the casting. Over time the rivets corrode the beam and the castings can then move under load and the platform will “walk” in the chop and waves which is slow.
- use Allen key head bolts on both inside and outside bolts. Discard any hexhead (normal head) bolts as they become troublesome over time. Allen key heads are easier to tighten in these tight casting space situation.
- use LOTS of grease. On the full length of the bolt shaft. Inside the captive nut in the castings. In the alloy casting holes. Everywhere possible. Stainless and alloy don’t like each other.
- don’t use silicone anywhere. It traps water and salt and contributes to corrosion. Use grease.
- remove the traveller rope anchor bracket. Apply anti corrosion compound between the stainless steel hoop and the alloy beam. Re rivet back on to beam. If you are keen, try bolting the stainless bracket with captive Riv-nuts. It will not go loose over time like the normal pop rivets do.
- apply an anti corrosive compound (or grease) on to outer casting where it slides into the beam. This will help if you need to remove the casting in the future. The castings are VERY expensive to buy. You want to look after them.
- when finished, try refurbishing the front beam castings too. After 20-30 years they will need some love.

_________________
John Forbes
Hobie 18 Reimagined
Sail # 490
Boat name: 18@heart
http://www.hobie18.fun
https://www.facebook.com/Hobie18catamaran/

If you go to my boats Facebook page, each photo that is published to help others has comments about it, not just the vision. Enjoy. There is lots to learn there.

_________________
John Forbes
Hobie 18 Reimagined
Sail # 490
Boat name: 18@heart
http://www.hobie18.fun
https://www.facebook.com/Hobie18catamaran/

Thank you all for your help!!!!

It really made all the difference (we didn't even think to loosen the front crossbar, so when identified, it was straight forward)!

Great !
Now go sailing......... yippee!

_________________
John Forbes
Hobie 18 Reimagined
Sail # 490
Boat name: 18@heart
http://www.hobie18.fun
https://www.facebook.com/Hobie18catamaran/