Boat Building Forum

Find advice on all aspects of building your own kayak, canoe or any lightweight boats

Cunningham/Sea Kayaker stitch-n-glue design flaw?
By:Dean Trexel
Date: 10/25/2001, 1:42 am

I'm in the process of putting the Chris Cunningham/ Sea Kayaker stitch-n-glue kayak in 3-D using my CAD software at work. I had plotted all the panels in 2-D a while back, but am just now trying to work those flat panels 'virtually' into the 3-D shape of the kayak. Things are going well (although slow), but I came across something odd. The forewardmost form shows a rocker of 30mm -- about 1-3/16". The rearwardmost form shows a rocker of 55mm -- about 2-3/16". Both of these forms are at the point where the keel starts to roll upward into the stem and stern, so the locations of these rocker values are accurate.

Long story short: there is 1" more rocker in the stern than in the bow. I've only seen one of these kayaks in person, and the owner had made a fixed skeg out of fiberglass about 1-1/2' long and about 1" deep at the stern, because he didn't build it with the retractable skeg that was included in the instructions and apparenly found out after-the-fact that it didn't track as well as he would have liked.

I thought that Greenland kayaks were made fairly symmetrical so that they handled running with and into the wind equally well. And if anything, the non-Greenland kayak designs I've seen had less rocker at the stern than at the bow.

I'm not sure how (or if) I'll fix this, I just thought I'd post this finding in case there are others out there considering building this kayak. The Seguin might be worth a harder look.

Dean

Messages In This Thread

Cunningham/Sea Kayaker stitch-n-glue design flaw?
Dean Trexel -- 10/25/2001, 1:42 am
Re: Cunningham/Sea Kayaker stitch-n-glue design fl
Pete Rudie -- 11/6/2001, 8:43 pm
And now for a word from the designer...
Pete Rudie -- 11/7/2001, 12:38 pm
Re: Cunningham/Sea Kayaker stitch-n-glue design fl
Dean Trexel -- 11/6/2001, 8:55 pm
Well, there you go, pilgrim... *NM*
Pete Rudie -- 11/6/2001, 9:27 pm
Which offsets are you using?
Pete Rudie -- 11/4/2001, 12:54 am
Re: Which offsets are you using?
Dean Trexel -- 11/4/2001, 9:49 pm
Re: Which offsets are you using?
Pete Rudie -- 11/5/2001, 12:15 pm
Re: Which offsets are you using?
Pete Rudie -- 11/4/2001, 1:26 pm
Re: Cunningham/Sea Kayaker stitch-n-glue design fl
Hans Friedel -- 10/26/2001, 6:23 am
Re: Cunningham/Sea Kayaker stitch-n-glue design fl
Richard Boyle -- 10/25/2001, 8:57 pm
Re: flaw vs. feature?
Mike Hanks -- 10/25/2001, 10:34 am
Re: flaw vs. feature?
Pete Rudie -- 11/4/2001, 1:35 pm
Inherent design feature
West -- 10/25/2001, 3:18 am