12 foot guideboat

12 foot guideboat

12 foot guideboat, 35 lbs in 4mm Okoume

This small light guideboat was intended as an easy to car top, one person boat.
Inspired by some of the small guideboats built many years ago (see Buyce and Parsons below), I drew up my first version years ago. Unsure if a 12 footer was worth developing the project was shelved.

Comparison of small guideboats
Design Length Beam Midship Height
Buyce 12′ 343/4 11″
Parsons 13′ 373/16 115/8
Parsons 12′ 36″ 115/8
Vermont Packboat 12’2″ 361/2 12″
Gardiner 12′ 363/4 12″

After Steve Kaulbeck’s Vermont Packboat was released some builders wanted to know if something similar was possible in plywood. They had tried a Packboat and thought it was great. So I dusted off my plans, which had some issues, and got to work.

Checking out the Packboat closely on water and land I concluded it was indeed a very decent little boat – the concept of a 12 foot guideboat was worthy of pursuit. The Packboat has a very clever concave bilge panel that helps tracking and primary stability (which would be very difficult to pull off with plywood) and is very well thought out and built. If you are considering a small kevlar rowboat that will move easily and can take some weather it should definitely be on your list. I admired it so I used it as a baseline for my revision.

A lot of changes to my original plans resulted in the 12 footer offered here. In the water it looks similar to the Packboat but there are some major differences.

front sections of the Vermont Packboat and the Gardiner 12 guideboat.

Gardiner12 on the left, Vermont Packboat on the right.  Front view of both.

In spite of only having a 12 foot hull the Packboat has excellent tracking. It gets it from the unique concave bilge panel which acts like a large keel, the strong hollow entry and exit of its waterline and the near flat rocker. Our boat runs a little deeper, with a narrower parabolic waterline (the two boats look as different in top down view as they do in the above graphic). We have slightly worse primary stability (feels tippier) and slightly better secondary.
I’m using a bit more rocker than Kaulbeck, but less than Buyce (see above), running between the masters can’t be all bad. Buyce picked up some stability with the extra rocker that was lost with his narrow beam, possibly at the expense of tracking. Design is all about compromise. I was worried about the tracking in my boat but in testing it goes well. Which of these boats is fastest should not be part of the conversation, with the 12 foot length, hull speed limits the top end. All of these small boats will move at a decent speed very very easily, and if a bit of weather comes up, well, so what.

A pair of prototypes were built at The John Gardner Chapter of the Traditional Small Craft Association (TSCA).
http://www.tsca.net/johngardner/sologuide.htm
and
http://www.tsca.net/johngardner/sologuide2.htm

Four more were built as a University of Conn course for students, with the TSCA.
Articles here: UConn Today and TheDay.com and
http://www.tsca.net/johngardner/uconn_class.htm (3 pages of pictures here)

Several more have been built since. One builder opted not to build with the strongback to save time and he reported that it went together well.