Old H16 mast head replacement

Hi Guys,
I am hoping to get some advice from someone who has replaced the original mast head with a comp tip mast head on a non comp tip mast. The sheave in the old mast head is falling apart. I decided to install a new style comp tip mast head rather than deal with making/having someone make a new sheave. I purchased the comp tip mast head and a new comptip main halyard.

The first issue is this. The rear sheave in the new mast head spins freely but the forward sheave does not because the steel bracket that holds the sheaves is pinched at the bottom of the forward sheave. It looks like the sheave bracket was not riveted onto the cap properly. I have included a picture but it might be hard to see this. I can turn the sheave with my finger but it takes quite a bit of effort. Is it designed this way? Should I send it back? Seems like for the price it should be perfect.

Secondly, I installed a mama bob float on the old mast head last year. I no longer have the instructions that came with the float but I remember that it came with the necessary hardware to install on old or new style mast head (does anyone have the installation sheet for the mama bob?). I was under the impression that the brackets that hold the float to the head line up with the center of the sheaves on the new head but that is not the case (see picture). I also have a picture of the hardware that I think came with the float, but I can't remember for sure what came with it. Maybe I have misplaced different brackets for the new style mast head. Any advice would be greatly appreciated!

Thanks, Don
BTW, I can't believe this little lightweight piece of stamped steel cost over $100, but it is what it is!

By shadmeall at 2010-07-17

By shadmeall at 2010-07-17

By shadmeall at 2010-07-17

All the bob installation instructions can be downloaded here at the Hobie website in pdf format. Open the home page and find the support link for cats.

I didn't know the comp tip mast head was a direct replacement for the all aluminum mast head. Are you sure this is going to fit?

Thanks for the bob installation link sunvisa. A few sources I found said the new style mast head would fit, but I won't be sure until I try. Right now I am struggling to get the old mast head off the mast. Do you have any idea how deep the casting goes into the mast? It looks like there is some kind of sealant there. Took 2 rivets out but it won't budge. Wonder if the casting goes all the way to the halyard fork rivets??

Thanks again,
Don

No, I have never removed one. Maybe one of the Hobie reps here can say how deep it goes. I suspect it is only an inch or so by the looks of the new one you have. You definitely need to break the sealant bond though. Can you get a razor knife around it? I'd try to heat it with a heat gun (paint stripper).

Well, it finally came off. I connected a 6" bolt thru the sheave pin hole on the masthead, connected to a chain, then to a tree. I connected another chain to the shroud attachment bracket further down the mast, then to a come along, and finally to the bumper of my truck. My neighbor and I cranked on the come along until the chains were taught (you could pluck them like a guitar string), but the masthead would not budge. Finally applied heat (like you suggested), using a mapp gas torch used for sweating copper fittings. I went around the top of the mast for a minute or so, and the mast head eased right out with no damage to the mast or severed limbs (the tree was ok too). Good guess on the depth, it was a little less than one inch. So the comp tip masthead does fit, but I need to decide whether to use the new mast head or maybe have a new sheave made for the old one (the sheave would be less money). Or maybe try to make one myself with a piece of delrin and a router. Decisions, decisions.

Thanks again for the advice sunvista.

Don

If you have already bought the comp tip mast head the how would a replacement sheave be cheaper? I found a guy online last year (Zephyrwerks.com) who said he would make me a replacement delrin sheave for $65. The only problem was that he needed my old one to template. Mine hadn't failed yet so I didn't want to take the boat out of service.

I have to send the new comp tip mast head back anyway because it's bent and one of the sheaves won't turn. I could get a refund, or ask for a replacement if the sheave doesn't work out. I emailed Zephyrwerks yesterday but have not heard back. My sheave is already out so I wouldn't mind sending it to him. What did you end up doing with your masthead sheave?

Well, like I said, mine hasn't failed yet but it is 28 years old and brittle. I guess I have just been "whistling through the graveyard" so to speak. Hoping it will get me through one more season. The guy I corresponded with at Zephyrwerks was Ed Louchard ([email protected]). If you have one made and it works tell Ed to save the pattern and let me know or let the whole forum know. There is probably a decent market here with all the aluminum masts still in service.

I still haven't heard from Ed at Zephyrwerks and it has been 3 days. I don't want to ship the sheave off unless I have confirmation from him. If I do go that route, I will be sure to let the board know and tell Ed that he potentially has a market for these sheaves. My boat is 30 years old and I know what you mean about brittle. The sheave has been laying around the house for a few days and is getting its share of abuse. "What this thing dad, oops, I dropped it".

If you think about is it's amazing they last as long as they do. My mast has always been stored outside with no cover. There was a period of several years when the masthead end of the mast was on the ground and was partially buried with dirt. It took forever to blow all that mud out with a hose.

I'll keep you posted, and in the mean time, no sailing for me

shadme: Have you checked with Surf City, another dealer, and/or the classifieds on a used replacement? I'd think those things would be a dime a dozen, but I guess they'd all be old. Out of curiosity, have you checked with a local machine shop on fabrication? Anyway, I think you're going in the right direction. I don't beleive the halyard for the all-Al mast will work right with the comp-tip masthead, and the halyard hook may even require relocation. Good luck and please let us know how it works out.

_________________
Jerome Vaughan
Hobie 16

No one that I can find carried these original replacement sheaves. I never heard back from zephyrwerks, so I guess I am on my own. I ended up sending back the comptip mast head and new style halyard, ordered a replacement original style halyard and made my own sheave. I didn't want to go with a used masthead because like you said, most of the sheaves are probably not in much better condition than mine. If you want to see how I made the sheave, see my post titled 'homemade sheave?'.

Thanks for the advice,

Don