Hobie Cat Forums

It is currently Mon Jul 28, 2014 2:21 am

All times are UTC - 8 hours [ DST ]




Post new topic Reply to topic  [ 37 posts ]  Go to page 1, 2, 3  Next
Author Message
PostPosted: Tue Nov 20, 2007 2:03 am 
Offline
Site Rank - Old Salt

Joined: Thu Aug 16, 2007 2:25 pm
Posts: 1948
Location: Central Coast NSW Australia
OK all you experienced sailors out there- I'm after some advice. The only sailing experience I have had has been with my Tandem Oasis and the standard Hobie sail. I have experienced 15 to 20 knot gusts and coped OK. I am able to furl it easily and I am now confident in any conditions. I have not capsized it yet!
I have long felt that the tandem could do with a bigger sail to improve its light /moderate wind sailing capability as it is a very stable craft. After much thought about bigger sails, longer masts etc I have come to the conclusion that the design of the mast tube makes that impossible.
I know some have added a jib but as I consider furling to be vital and for my front passengers comfort I have dismissed that.
I am now seriously thinking of something like this:
Image
I have almost perfected how to mount it. The extra sail would furl and be controlled by the passenger or myself when soloing.
Assuming my mounting system works OK is there anything I am missing, sailing wise, that is flawed with this system? The extra sail is a considerable expense and I want to be sure this project has some chance of success.
Any advice gratefully received.

.


Last edited by stringy on Wed Nov 21, 2007 3:46 pm, edited 1 time in total.

Top
 Profile  
 
 Post subject:
PostPosted: Tue Nov 20, 2007 11:48 pm 
Offline
Hobie Approved Guru

Joined: Sat Nov 12, 2005 10:46 pm
Posts: 2387
Location: Escondido
Stringy, what a bold and novel idea! One of the things you should consider is that normally the sail's center of effort is very close to the boat's center of lateral resistance. With your second sail so far forward of this center, you may have serious helm problems upwind. It may be correctable though with a daggerboard forward (if sailing solo).

Here's an article about this topic that discusses it in more detail:
http://www.boatus.com/goodoldboat/Helm_balance.asp

Good luck with this project -- I'd love to see you work it out! 8)


Top
 Profile  
 
 Post subject:
PostPosted: Wed Nov 21, 2007 6:36 am 
Offline
Authorized Hobie Dealer

Joined: Mon Jun 02, 2003 7:35 pm
Posts: 1370
Location: 315 N. Hwy 79 Panama City Beach, FL 32413 850-235-2281
How are you going to attach the front sail?

If you want to eliminate the front mirage drive you can modify a Mirage drive cassette plug, However I think the front mirage drive is crucial unless a dagger board is installed like roadrunner pointed out.

Take a look at the inflatable's sail. It has a very shallow mast base cup and uses shrouds, something that should be able to be modified to the front of the yak.

The 2nd major hurdle I see if how to run the sheet line for the forward sail. 2 sheet lines may be better with the 2 sheet blocks on the rails, it could be controlled from the rear seat like a jib on a sailboat. The angle of the front sail being sheeted on the rails could form a nice slot, if its sheeted in to far it might back wind the rear sail.

Please take pictures as you go and let us know how it turns out. I am sure you will get tons of ideas from the knowledgeable forum members.

_________________
Brad Stephens
Brad@sunjammers.com
(866) 786-5266 <--- Advice HOTline
http://www.sunjammers.com
www.facebook.com/sunjammers
Image


Top
 Profile  
 
 Post subject:
PostPosted: Wed Nov 21, 2007 4:14 pm 
Offline
Site Rank - Old Salt

Joined: Thu Aug 16, 2007 2:25 pm
Posts: 1948
Location: Central Coast NSW Australia
RR -thanks for the info and the link -very informative- I can see I have a lot to learn regarding sailing. I enjoy tinkering so I will keep going and let you know how it goes. You have had both old and new tandems. Did you notice a difference when sailing the newer with the mast located further back?

Sunjammers- I am still hunting up parts but basically I am welding up a framework that uses the existing screw mounts for the front hatch. It will be removable. I will not be eliminating the front mirage drive as it's important when a passenger is aboard. I am hoping it will act as a centreboard. Solo though is different and I may have to combine a centreboard with a ballasted mirage plug. Kepnutz posted some pictures in a previous thread that may be helpful but I am jumping ahead a bit as I still have to finish the mast mount. The inflatable's mast may have to be used if the hatch mounts turn out to be too flexible but I prefer the simplicity of the original mast- just drop it in and go -and also for furling.
Thanks again for the great info :D


Top
 Profile  
 
 Post subject:
PostPosted: Wed Nov 21, 2007 5:11 pm 
Offline
Site Rank - Admiral

Joined: Thu Sep 21, 2006 4:54 pm
Posts: 215
Location: Seattle, Washington
If there were only a tandem Adventure Island, Oh wouldn't that be great!

_________________
Mike Hensel
Hobie Tiger
Wind in your sails, water in your shoes, great day!


Top
 Profile  
 
 Post subject:
PostPosted: Wed Nov 21, 2007 11:21 pm 
Offline
Hobie Approved Guru

Joined: Sat Nov 12, 2005 10:46 pm
Posts: 2387
Location: Escondido
stringy wrote:
Did you notice a difference when sailing the newer with the mast located further back?:D

Our old Tandem was built before sails became an option, so it had no sailing capability. But I did notice when sailing the new boat solo without ballast, the nose is up, shifting the CLR aft. The CE is then further forward of the CLR. Even this small difference gives a very heavy weather helm, slowing the boat and making it hard to point upwind.

If your new sail causes a similar problem (with both Drives in) you can always add a leeboard. There is a discussion here (pics have been removed) by Lone Wolf. He build a very nice metal leeboard. If you PM him (from that forum), he could probably send you the pics. Like you, he has some excellent metal skills. http://kfs.infopop.cc/eve/forums/a/tpc/ ... 7321057602

Here's another sail innovator, punchinello, on the KFS forum using a leeboard on his Sport. You can do a search of his posts on that site: http://kfs.infopop.cc/groupee_files/att ... sportt.JPG

He also posts here as norman ernsting. This link has some close-ups of one of his wooden leeboards on an Outback: http://www.hobiecat.com/community/viewt ... ght=norman

The advantages of a leeboard are that you have more placement options and they can be used solo or tandem. 8)


Top
 Profile  
 
 Post subject:
PostPosted: Thu Nov 22, 2007 12:06 am 
Offline
Site Rank - Old Salt

Joined: Thu Aug 16, 2007 2:25 pm
Posts: 1948
Location: Central Coast NSW Australia
Great info -thanks RR.
PS- How do you get quotes highlighted like that? I have tried but not got it right.


Top
 Profile  
 
 Post subject: sail
PostPosted: Thu Nov 22, 2007 7:48 am 
Offline
Site Rank - Old Salt

Joined: Thu Jul 27, 2006 4:50 pm
Posts: 461
Location: sacramento california
How Ya Going Stringy !

I like your idea to improve or make a bigger/double sail for the tandem model.
The standard sail might work well enough for the single kayak models but with the weight of two adults and gear in our tandem oasis the sail does not always seem to move the boat very much unless the winds are on the verge of hurricane speeds. At this point our mast and rigging is just about to break when the wind and standard sail finally start to move the boat along a bit. :x

Any way I had a half baked idea after seeing your post about using two sails that I thought Id throw out for the heck of it and it might look something like this instead

Image


By using pvc maybe the hull would not have to be modified with a forward mast tube at all.
The main mast tube could hold two side by side sails mounted onto a horizontal pvc tube with another pvc mast tube placed on either end to hold each sail.

I havent figured out any rigging or structural analysis but the sails could be spread apart a bit and perhaps controlled in tandem by the same sheet similar to a hobie tri foiler design.
The two sails would then be placed outboard of the hull and have some type of float/ama/aka setup attached to the ends to reduce any heeling/ tipping. The front passenger could then still pedal and paddle with both sails out to the side etc. etc.
Anyway just a half baked idea to ponder.
Have fun down under

Kepnutz


Top
 Profile  
 
 Post subject:
PostPosted: Thu Nov 22, 2007 6:13 pm 
Offline
Site Rank - Old Salt

Joined: Thu Aug 16, 2007 2:25 pm
Posts: 1948
Location: Central Coast NSW Australia
G'Day Kep,
Thanks for your contribution. :D
When I first started thinking about improving the sail back in April the consensus was that you couldn't go bigger without adding amas -same as the AI. Then I came across the Hobie Trifoiler after seeing it mentioned here. I had never heard of it before and researched it a bit more. What an amazing sailboat!
It's scary how close what you have drawn is to what I was thinking back then. Great minds and all that! :wink:
I almost bought 2 small closed cell foam moulded surfboards with a hard plastic bottom to use as amas. I was going to adapt the Hobie sidekicks for akas and mount the sails just like the trifoiler.
As my confidence grew with sailing though I went away from the amas idea. I like the way the kayak heels when under sail. I like the simplicity of a single hull especially as I am now wheeling it about 1.5 kms 2 days a week to get to work. (it's easier than putting it on the car for the trip to the boat ramp). A couple of negative posts about akas breaking and mounts popping made me realise that they subject the boat to a fair bit of force in certain conditions.
I am close to finishing the mast mount and I haven't had to modify the hull. It uses the existing holes on the front hatch. Next will be to test it. It may be too unstable of course and amas may be necessary but I will have to try it first.
Who knows-ultimately I might end up with something similar to what you have drawn? :wink:


Top
 Profile  
 
 Post subject:
PostPosted: Thu Nov 22, 2007 11:24 pm 
Offline
Hobie Approved Guru

Joined: Sat Nov 12, 2005 10:46 pm
Posts: 2387
Location: Escondido
Stringy, to send a link, first open your post that you're working on. When you get to where you want to insert a link, open another window and go to that site. Once it is open, click on the http (address) line at the top of the screen and it will turn blue. then right click on it, select "copy" and switch back to your post.

Place the cursor where you want to insert the link, right click it and select "paste". I'm not sure if it's necessary, but I leave a space ahead and behind the link or place it on its own line. When your post is done, it should automatically show up as blue or purple, confirming your success. It's very similar to hosting a picture, except that you don't need the host. 8)


Top
 Profile  
 
 Post subject:
PostPosted: Fri Nov 23, 2007 4:46 am 
Offline
Site Rank - Old Salt

Joined: Thu Aug 16, 2007 2:25 pm
Posts: 1948
Location: Central Coast NSW Australia
Thanks RR but I meant how do you get your quotes in that separate box? (not links- I can do those already). Like you posted 'stringy wrote' and then the quote is in a separate box with a different coloured background.
Sorry for the confusion.


Top
 Profile  
 
 Post subject: Re: sail
PostPosted: Fri Nov 23, 2007 5:17 am 
Offline
Site Rank - Old Salt

Joined: Thu Aug 16, 2007 2:25 pm
Posts: 1948
Location: Central Coast NSW Australia
kepnutz wrote:
The standard sail might work well enough for the single kayak models but with the weight of two adults and gear in our tandem oasis the sail does not always seem to move the boat very much unless the winds are on the verge of hurricane speeds. At this point our mast and rigging is just about to break when the wind and standard sail finally start to move the boat along a bit. :x

Kep- I totally agree -hence this project. I'm hoping the negative of the 2 bendy shorter masts will actually be a positive - preventing a capsize by allowing air to wash off better than if it were one 40sqft sail with a stiffer taller mast.

RR-Obviously forget my previous post :wink:


Top
 Profile  
 
 Post subject:
PostPosted: Thu Nov 29, 2007 10:32 pm 
Offline
Site Rank - Old Salt

Joined: Thu Aug 16, 2007 2:25 pm
Posts: 1948
Location: Central Coast NSW Australia
Well I've finally finished the mount for the second sail. It took me longer than I thought but I think it's going to work OK.
Image
I made it so the hatch can still be opened
Image

I rotated the hatch 180 degrees to make access easier.
Image

I can still use my original roller furling mod which works well.
Image

Image
My local Hobie dealer is letting me try a second sail which I will pick up tomorrow.
I'll post the results of my trials as soon as I can. :D


Top
 Profile  
 
 Post subject:
PostPosted: Sun Dec 02, 2007 9:48 pm 
Offline
Hobie Approved Guru

Joined: Sat Nov 12, 2005 10:46 pm
Posts: 2387
Location: Escondido
Stringy, your mod looks great! Have you had a chance to try it out yet?

I was hoping to see how you ran the forward mainsheet and furling line -- it seems like the sheet would connect right about where you're sitting, unless you're running two sheets like a jib?? 8)


Top
 Profile  
 
 Post subject:
PostPosted: Mon Dec 03, 2007 3:43 am 
Offline
Site Rank - Old Salt

Joined: Thu Aug 16, 2007 2:25 pm
Posts: 1948
Location: Central Coast NSW Australia
G'Day RR,
You wouldn't believe it but since I picked the second sail up we have had terrible weather with thunderstorms on all but one day and that day I got called in to work :( -so I haven't been able to try it yet.
As usual you are spot on with your observations!
I have had some time to play around with it more and today I finished off what I hope will be a working sheeting arrangement.
Thanks to Sunjammers who suggested a twin sheet jib-type arrangement I did a bit more research and looked at how others had set up their jib. To avoid hitting the rear mast I think a twin sheet is the only option.
I have mounted a sheet block in each rear footwell just forward of the drinkholder/ mesh pocket. A jam cleat either side locks the sheet. I also want to be able to give the front passenger sheet control so I have used swivelling blocks that should allow this.
I will post pics soon but I am really keen to get on the water and report back with something positive, sadly the bad weather is forecast to continue most of this week. :cry:


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 37 posts ]  Go to page 1, 2, 3  Next

All times are UTC - 8 hours [ DST ]


Who is online

Users browsing this forum: Yahoo [Bot] and 1 guest


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum

Search for:
Jump to:  
Powered by phpBB® Forum Software © phpBB Group