Hobie Cat Forums

It is currently Fri Nov 28, 2014 2:51 pm

All times are UTC - 8 hours [ DST ]

Post new topic Reply to topic  [ 38 posts ]  Go to page Previous  1, 2, 3
Author Message
PostPosted: Thu Jan 31, 2013 2:31 am 
Site Rank - Old Salt

Joined: Wed Oct 19, 2011 6:02 am
Posts: 325
Location: Cape Coral, FL
yaknrugger wrote:
stringy wrote:
I came to hate a number of issues when sailing in good winds with the MD in:
-it was slower. The MD in either position adds drag.
-you could feel the fins fluttering at speed. I felt this might contribute to wear on the drive and unecessary extra force on the drivewell ledge.
-they would catch weed
-they were more prone to damage from hitting things.
-the cockpit felt cramped
So if I'm not pedaling then the drive is removed (but kept handy and leashed).

Sorry, not to hijack the thread, but a quick question about removing the MD's to increase performance in a good wind. Is there any additional benefit (speed or otherwise) by adding the drive well blanks when the MD's are not in?

I've noticed a slight increase in speed (.1~.3 knots) and faster, more bombproof tacking. Tacks like a machine. Of course, if you blow the tack without the MD installed, you're boned. I always pull the drive in winds between 5 & 20, above and below that the drive remains installed.


A PVC lock is a cool idea, I might make one for windy days.

2011 Golden Papaya TI with a 250 square foot spinnaker!
also a more manageable 100 square foot spinny...
the TI3 rear ama mod

PostPosted: Thu Jan 31, 2013 4:39 am 
Site Rank - Old Salt

Joined: Thu Aug 16, 2007 2:25 pm
Posts: 2069
Location: Central Coast NSW Australia
Tom Kirkman wrote:
I can't really speak to an increase of speed by removing the Mirage Drive. I haven't noticed it but then I haven't really bothered to check it against a GPS or anything. I will say that when the Mirage Drive is pulled you greatly reduce noise and splash by installing the well plug. Speedwise, I just can't say. I haven't done any legitimate comparisons. I'm sure somebody else has.

I haven't done legitimate comparisons either when sailing. Too many variables. It certainly feels faster and does tack better as K7 noted. (BTW if you miss the tack, reversing the rudder direction gets you out of 'irons' and sailing again)

I have done some GPS comparisons though, in kayak mode. Paddling without the drive in, rudder up and in flat conditions I can comfortably average around 7km/h. Putting the drive in and paddling, that average drops to around 6.5km/h. Interestingly that stays the same whether the fins are folded up against the hull or 'locked' down. Adding the drivewell plug makes no difference to speed but it does stop water surging up and over the 8" hatch cover.

PostPosted: Tue Feb 05, 2013 3:20 pm 
Site Rank - Captain

Joined: Mon Mar 26, 2012 10:37 pm
Posts: 92
Location: Puget Sound, Washington USA
A velcro strap can indeed be used, but it won't hold the pedal arms as straight and parallel as this tool will. If it would, I wouldn't have bothered with this. Yes, I tried it.


I suspected as much. You probably need all the stiffness you can get since the flippers were not designed to be a dagger board. I've often wondered if they added some dagger board function when sailing. There was a good discussion here a few months ago about that with strong and good arguments on both sides.

I can also understand the convenience of your approach. Sliding up on the hatch cover is not as easy for me now as it would have been 30 years ago.

PostPosted: Tue Feb 05, 2013 4:32 pm 
Site Rank - Old Salt

Joined: Tue May 18, 2010 2:31 pm
Posts: 2755
Location: Kailua 96734
Kman7, I lack a way to accurately meter speed changes that small, but when I remove both the dagger and Mdrive, I can tell that my mid-level speed ramps up some. In moderate conditions, the boat feels more slippery.

By slippery, I am referring to speed made good, rather than leeway.

Riding on the Hakas may have some influence here, because when I try this, I'm surprised at how well the boat points while close-hauled on a starboard tack.

Those of you riding the benches may want to try this. Let me know if your results agree with mine.

And I'll check to see if the tacking is improved without the drive, as you suggest.

PostPosted: Tue Feb 05, 2013 7:08 pm 
Site Rank - Old Salt

Joined: Fri Dec 05, 2008 2:32 am
Posts: 1790
Location: Terrigal NSW, Australia
NOHUHU, I certainly concur that hiking out seems to make the boat point higher - on either tack, but more so on a starboard tack. It makes sense, as the daggerboard is going to "bite" better with the boat flat.

I don't know to what extent it's my "roll-tacking" technique on the quarterdeck and to what extent it's the larger rudder, but I find the AI now tacks exceptionally well without the drive in - virtually zero failure rate.

Hiked out, with the drive pulled, is a very catamaran like experience.


PostPosted: Sun Mar 17, 2013 11:04 am 
Site Rank - Deck Hand

Joined: Sat Dec 19, 2009 4:35 pm
Posts: 24
What if the miragedrive plug had a small daggerboard?

PostPosted: Mon Mar 18, 2013 11:12 am 
Site Rank - Old Salt

Joined: Tue Jul 19, 2005 6:29 pm
Posts: 2094
Location: High Point, NC
That's an interesting idea. Assuming it wouldn't put too much side pressure on the MD fasteners or the hull in that area, it might be an idea well worth considering.

PostPosted: Fri Mar 22, 2013 7:31 pm 
Site Rank - Captain

Joined: Sat Jul 28, 2012 4:21 am
Posts: 71
Well thats a cool solution and simple to make Tom. I often feel as though i require the 'centreboard' effect from the fins straight down and in-line because sailing in Darwin as we have frustratingly high tides and strong tidal currents that often stuff up an otherwise perfect sailing day. :x
I like your simple solution too Slaughter, with your set-up the hook remains attached to the boat and can't get lost. Like I always say, we AI/TI owners are an innovative lot :wink:
Cheers Vintagereplica
If it works okay...modify it anyway!

Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 38 posts ]  Go to page Previous  1, 2, 3

All times are UTC - 8 hours [ DST ]

Who is online

Users browsing this forum: Google [Bot] and 3 guests

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