Friday, January 20, 2017

Header Photo: William F. Crosby "Pup" Dinghy

The previous header photo was the side view of Crosby's Pup dinghy, a V-chine design published in the August 1938 issue of Rudder magazine. What is interesting about this design is Pup is one of the first dinghies designed to be built in plywood. Even more surprising is Crosby specified 1/8 inch (3 mm.) plywood for the hull and decks. Crosby seemed to have no fear, this early on, in pushing the structural limits by using very thin plywood. (Designers post WWII such as Phil Rhodes with his Penguin dinghy would revert back to the sturdier 1/4 inch (6 mm.) plywood for the hull.)  To account for the flexibility of the plywood, Crosby added one fore and aft stringer and two smaller, intermediate frames between the major plywood frames.

The Pup dinghy may be one of those "missing links" I am so fond of speculating about in sailing history. I have always wondered what spurred the Australians into wholesale acceptance of thin, lightweight plywood for their dinghies designed after WWII. (The Aussies would even convert their pre-WWII plank on frame designs before WWII over to light ply, their existing VJ class and 12 meter Olympic Sharpie.) I received an email from a South Australian dinghy sailor two years ago and he mentioned that he owned an Aussie Pup built by a local builder in the early 2000's. He also mentioned there was a sizable fleet of Pups in the Melbourne area in the 1940's but they had died out.

Could it be that some Melbourne sailors, in building the 1/8 inch ply Pup before World War II, would become the impetus of the Australian revolution in lightweight dinghies? Certainly South Australian Len Morris with his scow Moth would have taken notice as he would produce his superbly engineered, light plywood Mk II in the late 1940's. It would be an interesting slice of dinghy memorabilia if someone could dig up some photos of the Melbourne Pup fleet in the 1940's.

For those that want more information, Steve Clark pointed out, in the comments section, the current builder of the Australian Pup has a Facebook page.

A JPEG file of the Pup plans as they appeared in Rudder magazine, 1938.


Alden Smith said...

Really nice little sailboat - as good looking as the Crosby catboats!

Alden Smith said...

..... I had another read of this post - It is amazing that 1/8th inch plywood was specified, this is not much stronger (certainly not more puncture proof) than a hull covered in painted canvas.

I love the old sailing magazines - they often used to publish plans like this complete with the table of offsets for any enterprising sailor to have a go at building..... and again, those Crosbys, they certainly knew how to design a pretty boat.

Stephen Clark said...
Group in Geelong Victoria Australia has been developing a modern derivative.
Noty sure I agree with all changes, but someone is doiung something with this pretty nice little design.

Tweezerman said...

Thanks Steve! I pulled the link over to the main post.