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Is it possible to fit an 18 mast onto a 17?
http://www.hobie.com/au/en/forums/viewtopic.php?f=9&t=4369
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Author:  ozglxvr6 [ Sat Jul 29, 2006 8:41 pm ]
Post subject:  Is it possible to fit an 18 mast onto a 17?

Just Curious.... can it be done? What would it take to do?

( Edit: bumped this thread 9-2-2008 - project is almost complete :) )

Author:  The Dog [ Sun Jul 30, 2006 8:08 am ]
Post subject: 

The mast bases on the 18 and 17 are different. And working from memory, I believe that the mast extrusion on the 17 is smaller than the 18, so you'd be unable to install an 18 mast base into a 17 mast....

But I'm at home and the parts are at the shop, so I could be way off.

Brian C

Author:  ncmbm [ Mon Jul 31, 2006 8:31 am ]
Post subject: 

I think it can be done. Options are replace the bearing setup or the mast base. The extrusions are the same I believe, so the base replacement should be easiest. Standing rigging will be an issue, will be custom I feel sure. Pricey too.

Author:  sunjammers [ Mon Jul 31, 2006 8:47 am ]
Post subject: 

As long as the masts are the same diameter them bases will fit.....I think they are different thou, I am out of both bases so I can't compare.

Author:  ozglxvr6 [ Mon Jul 31, 2006 9:20 am ]
Post subject: 

ncmbm wrote:
I think it can be done. Options are replace the bearing setup or the mast base. The extrusions are the same I believe, so the base replacement should be easiest. Standing rigging will be an issue, will be custom I feel sure. Pricey too.


The rigging pricing doesn't matter too much. My brother just called me and told me I am getting an 18 mast for free. :)

I tried to check out the parts diagram in the hobie catalogue, but it really doesn't show much. Can someone take a picture of the base of an 18 mast? I probably won't be able to pick it up until this weekend. I wan't to start ordering any parts that I need...

Thanks for all of your help!

Author:  The Dog [ Tue Aug 01, 2006 7:28 am ]
Post subject: 

Looks like my memory is going...

I just held a H-17 mast base casting up to a H-18 mast base casting here at the shop. It sure looks like they have the same mast extrustion. So other than the logistics of wires, the eyeball says the H-17 mast base will fit into the H-18 mast.

Brian C

Author:  ozglxvr6 [ Tue Aug 01, 2006 12:07 pm ]
Post subject: 

The Dog wrote:
Looks like my memory is going...

I just held a H-17 mast base casting up to a H-18 mast base casting here at the shop. It sure looks like they have the same mast extrustion. So other than the logistics of wires, the eyeball says the H-17 mast base will fit into the H-18 mast.

Brian C


Great! How much can you sell me a mast base for?

Author:  ncmbm [ Tue Aug 01, 2006 3:25 pm ]
Post subject: 

You need to be sure the mast step and dolphin striker config are strong enough to hold the 18 mast and sails. It would be a shame for your crossbar to collapse under the load. 17 standing rigging won't work and don't believe 18 rigging will either but I'd start there. Maybe get some used rigging to fit for size and then purchase new. What will you use for sails?

Author:  The Dog [ Tue Aug 01, 2006 7:29 pm ]
Post subject: 

ozglxvr6 wrote:
The Dog wrote:
Looks like my memory is going...

I just held a H-17 mast base casting up to a H-18 mast base casting here at the shop. It sure looks like they have the same mast extrustion. So other than the logistics of wires, the eyeball says the H-17 mast base will fit into the H-18 mast.

Brian C


Great! How much can you sell me a mast base for?


Sorry... I'm finally at home after a long day working the shop solo, and just saw your post. If you're serious:

http://www.mariner-sails.com/partdetail.asp?id=24014

That's just the casting and not all the misc parts that make up the base (bolt, sheeves, etc). The H-17 mast breakdown is here:

http://www.mariner-sails.com/assembly.asp?id=23189

Like ncmbm, I'm not sure what you're planning is a real good idea. The loads are way different. That Matt hasn't chimed in is interesting.

Brian C

Author:  ozglxvr6 [ Tue Aug 01, 2006 7:32 pm ]
Post subject: 

The Dog wrote:
ozglxvr6 wrote:
The Dog wrote:
Looks like my memory is going...

I just held a H-17 mast base casting up to a H-18 mast base casting here at the shop. It sure looks like they have the same mast extrustion. So other than the logistics of wires, the eyeball says the H-17 mast base will fit into the H-18 mast.

Brian C


Great! How much can you sell me a mast base for?


Sorry... I'm finally at home after a long day working the shop solo, and just saw your post. If you're serious:

http://www.mariner-sails.com/partdetail.asp?id=24014

That's just the casting and not all the misc parts that make up the base (bolt, sheeves, etc). The H-17 mast breakdown is here:

http://www.mariner-sails.com/assembly.asp?id=23189

Like ncmbm, I'm not sure what you're planning is a real good idea. The loads are way different. That Matt hasn't chimed in is interesting.

Brian C


Does 2 feet of mast make that much of a difference? It would seem that the boat is engineered to withstand quite a bit more force than it would normally take, for longevity purposes.

I would most likely be using 18 sails.

Thanks!

Dave

Author:  The Dog [ Tue Aug 01, 2006 7:52 pm ]
Post subject: 

ozglxvr6 wrote:
The Dog wrote:

Like ncmbm, I'm not sure what you're planning is a real good idea. The loads are way different. That Matt hasn't chimed in is interesting.

Brian C


Does 2 feet of mast make that much of a difference? It would seem that the boat is engineered to withstand quite a bit more force than it would normally take, for longevity purposes.

I would most likely be using 18 sails.

Thanks!

Dave


Those are questions best asked of the boat designers....

But while I'm just a "grunt" at a Authorized Hobie Dealer, I am also a retired engineer.

And every design has a margin of error. What you propose will definitely eat into the margin of the 17.... A lot. The 18 rig is bigger and heavier. Period.

What you need to consider is not just the mast height. You also need to think about the difference in sail area, center of effort in the rig, differences in the shroud anchor points and the whole jib issue. Plus, the 17 hulls are much finer than 18 hulls.

My 17 was one of the early ones (3rd one in Texas). While it was a fine boat (which I used and abused before I knew better), I would not do what you're proposing even to hulls fresh off the line. And that's from someone who likes to push limits and gave up Hobie cats because they were "slow".

So while I shared that the H-17 and 18 masts seem to share an extrusion, my advice is:

Don't do it.

Brian C

p.s. edited to trim quotes

Author:  ALEXSAILS [ Tue Aug 01, 2006 9:35 pm ]
Post subject: 

Brian, Why did u realy give up on Hobie Cats???

Author:  ncmbm [ Wed Aug 02, 2006 6:37 am ]
Post subject: 

H18 dacron sails are heavy and your boat currently uses a mylar/dacron which is considerably lighter and won't hold moisture like the 18 sails. I'm all about hotrodding the boat but a squaretop main and schreecher sail would be a better plan. Look at the pics of "Stress Free" in the post, show us those boats! Try what you like but I'm afraid you will break something or worse, get hurt.

Author:  ozglxvr6 [ Wed Aug 02, 2006 8:25 am ]
Post subject: 

After some research... an 18 mast is only 6" taller than an 17sx mast... if they use the same extrusion, how can the actual mast be that much heavier?

I can understand the fact that the sails will have more surface area... but wouldn't that same attribute prevent anyone from using a flat top sail?

What would prevent me from using a 17 SE sail with the 18 mast? Won't it just be 6" higher than with a 17 mast?

17 SE mast length: 27'7"
17 SE sail area: 168 Sq ft

18 mast length: 28'1"
18 sail area: 240 Sq ft

Author:  ozglxvr6 [ Wed Aug 02, 2006 8:35 am ]
Post subject: 

I suppose I should explain my situation!

I just bought 17 that is missing the mast, rigging, sails, and a rudder.

A friend is giving me an 18 mast, rigging and hopefully the rudder parts I need. I may be getting the hulls and wings as well, but I have a feeling they are pretty torn up. (my friend was using it as a grinding rail for wakeboarding...)

I wish to get a complete boat out of the two!

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