H16 Rudder castings on an 18?

Ok havent been at this for long but if i get some h16 rudder castings that actually pop when you hit a beach will they work to replace the h18 old Pre-87 type? I guess you would have to replace the whole mechanism?>

H-16 Rudder castings are TOTALLY Different that those used on the H-18.
there is NO interchangeability in any way shape or form.
Even if it could be done it would bastardise the boat in one of the worst possible ways.

Not only would you have to replace the whole mechanism, you'd have to re-position the gudeons on the transom (and the aluminum backing plates on the inside) as well as craft new tillers, since the old 18 tillers are nothing like the 16's.

You're better off looking for new-used 17 / 18 / Wave hardware.

Ok I didnt think about the plate in the hull. What would be my least expensive option for this? Look for used from 17 or wave? Can I use the lower from a newer and the upper from the older? I am just trying to create an inexpensive beach cat to play with, not a racer.

I've posted about this before, but here is a quick run-down of how I've made the old style castings work.

The trick is to run with the cam spring at very low tension- just barely enough to keep the tiller arm from inadvertently lifting. Then use bungee cord wrapped around the rudder and rudder pin to hold the rudder down (two wraps is good). I like to use bungee cord with hooks on the ends so I can relieve the tension when not in use. I belive murrays also still sells the special "flanged washers" that go on the outside of the lower casting bolt to help hold the bungee down. It's called the rudder hold down kit or something like that. Last step is to lightly grease the contact surface where the cam and the lock-down pin on the upper casting meet.

When I come in, I generally still raise the tiller arm before hitting bottom just to be safe (the arm never jams because the spring tension is low and the cam is lubed). But on the occassions when I've misjudged the depth, the rudders have kicked up on their own.

sm

The "old" and "new" H18 rudder castings are totally different designs. The castings are a "matched set" design: upper/lowwer . The only way you could mix the different design is Port/Starb, w/ a different set on either side ... But why would you want to do that??? . The "old' H18 rudder castings were used ONLY on the H18. The "new" H18 rudder castings were introduced at the same time as the H17 was and are the same castings. I do not know if the "tiller arm" extentions are the same, they maybe different lengths for the two boats. (Matt B, would you know the answer to this question?)

Now it has been MANY years since I had to do a conversion (and I have many grey hairs now) but I seem to remember that you had to "flip" the lowwer gudgeon over and "drill/tap" the two new upper holes for the lowwer gudgeon ...

(Stephen or Matt B am I remembering this correctly???)

You are in Florida ? ... Salt Water? ....

Use SS Rudder pins and do not forget the little white plastic BUSHINGS ... very important as it prevents the SS Rudder pin from wearing away the ALUM Rudder Casting. One part costs $15-20's .... the other +$150.00's ... (quess which one wears out!!!) I currently have TWO sets of rudder castings that the previous owners forgot about these $1.00 bushings and the castings are trash unless I can get the en-larged hole filled in and re-drilled or have some sort of "insert/bushing" pressed in.

Ol'Timer Trick: Place a 3/8" SS Washer on top of the upper gudgeon and between the rudder casting, this will act as a "bearing surface" and prevent the SS Gudgeon from wearing into/away at the rudder casting as gravity "pulls down" on the castings and rudder ... it also helps the plastic bushings to last longer.

Harry

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HarryMurphey
H-18 mag/ #9458
Fleet 54 Div 11

Harry, I made a couple of jigs to bore out H-16 and H-18 rudder castings. Nice & straight, as the drill/reamer is running through drill bushings. You can buy different wall thickness bushings or just use a JB weld for aluminum and then bore out.

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1989 Hobie 18 Worlds Boat, Magnum Wings & Spinnaker
1987 Hobie Holder 20 #273

dale.vanlopik"at"att"dot"net

Hi DVL,

Thank you for "posting in". So you have been able to resurrect a H18 Lowwer Casting??? I am very interested in discussing this procedure in greater detail, could you E-mail me? My E-mail address is listed in my profile. Having been a Manufacturing Eng at one time in my varied career I know that the "devil is in the details" and if you would be so kind to educate me w/ a proper procedure I would be greatful.

Harry

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HarryMurphey
H-18 mag/ #9458
Fleet 54 Div 11