Jump to content

Anyone ever heard of this design before


DanSkorupka

Recommended Posts

Has anyone ever heard of Happy Clam by John Atkin. The plans were for the longest time not on the Atkin's plan website.

It is an inboard powered vee bottom boat with a large box keel, derived from the Seabright skiff, but very different from the pulling boats and fast runabouts also given the Seabright skiff name.

It is 17 feet LOA, 16 feet LWL, displaces 900 lb empty, and draws 11 1/2 inches.

Its most impressive feature is its economy; it will plane with 5 hp at 14 mph, and the designer expected 20 mph with a 10 horsepower motor.

It is a complex hull form, but the topsides are conventional lapstrake (clinker) type and have a large margin for error. It is a time consuming build; it took a commercial shop 428 hours to build it in 1950. I have never built a boat, and have a poor sense of time, so I do not know how long it would take an amateur to construct it. I do not believe I could do it myself as designed.

full plans can be purchased here for $45 USD

and

A scan of the study plans as posted in Mechanix Illustrated is available as a large (1.45 MB) pdf Here

I wonder if it could be built in fiberglass on foam core and get good results. I know little about the relative merits of various materials and techniques, but have read that fiberglass is a good option for complex hull forms.

I also am wondering if a modern substitute could be found for the old marine engines. Beta Marine engines makes marinized Kubota diesels as small as 10 hp and has multiple local distributors, but I could hardly afford the exhaust system alone. Honda makes its commercial air cooled small engines available with six to one or now also a two to one reduction gear as an option.

Has anyone ever seen one in person or heard of one being built in recent decades, especially by different materials or methods than called for in the original plans. I saw a photo of a non tunnel stern vee botom seabright of 17 or so feet in length, with a large box keel built in fiberglass, and a caption saying these are common somewhere. I cant find it anymore, but it is shown upside down and is white both topsides and below waterline. The website does not use the words seabright skiff, so I cant google it. Has any one seen this photo?

Link to comment
Share on other sites


Wanderer, The Atkins web site is a lovely place to browse for antique hull forms and personally owning one of the last commissions that John drew up myself, I can assure you that the half a century since this era, has produced considerable hull form development. My boat is a large box keel design (39'), his last of this type and I know a fair bit about the the hull form. Sea Brites are a bit different, though do share the box keel concept. These have some advantages to them, if you want to run an inboard (why), but they also, like everything, have bad points to consider.

I don't know if you've owned an inboard boat before, but the handling manners on them, couldn't be described as "crisp" to say the least. Combine a box keel with an inboard and you get a boat that tracks well, has way too much drag to get over the high teens unless it's very light and forget about backing up, in any other direction then the side the prop walks to. Compared to an outboard powered craft of similar size and weight, it'll be a slug in most every regard, except low speed fuel economy.

The Rescue minor is a better example of this hull form as it was the last of it's type and fully developed. The reverse along the rabbit is refined as is the inverted V aft. This took a far bit of development by both Billy and John during their Careers. John finally go it right in the late 50's.

All the above said, these are designs that are a half a century old. Expectations of modern ride, crisp handling, safety considerations (splash wells, floatation, etc.), comfort, economy and accommodations can be tossed right out the window. The plans available from Atkins come with very little more then a set of lines, the offsets and the construction plan and profiles, maybe a BOM. That's about it. You'll also get a little magazine article about the design, printed when ever the boat was featured (1920's - 1950's). This is why you can buy the full plans to a 50' yacht for $40, instead of $1,500, like every place else. I guess my point is, be careful what you wish for . . .

Link to comment
Share on other sites

I have no need and no desire to go faster than the teens. I was given the privilege of piloting the ww2 amphibious landing craft "Red Sox Nathan" on the Charles river and part of Boston harbor when my high school chartered the Boston duck tours. It was the first time I ever piloted an inboard, and the first time using a steering wheel instead of a tiller. I enjoyed it quite a bit, and found it to be a steering response I got along adequately with. There was little more difficulty in handling than a certain rental skiff on cape cod with a normal outboard, I got used to it nearly as quickly as I got used to oars.

I certainly hope Happy Clam would be more maneuverable than Red Sox Nathan.

The fastest I have ever been on the water was with a 10 foot jon boat, and a Johnson weedless 4 hp seahorse. About 20 mph I guess (couldn't measure), and the engine didn't HAVE a reverse or even a clutch or neutral gear. Obviously the larger, heaver, more streamlined boat will coast further, and benefit more from a reverse. Even so I could leave the tiller and get up front even while flying through the meanders of the upper Charles, which probably gives a much shorter opportunity to respond.

Regardless I do admit that a modern craft, with a shallower draft no box keel and outboard would be a more comfortable, easier to handle, faster, and although easy to get into trouble in, would be safer when a problem did arise.

My boat would spend most of its time on slow, calm rivers sightseeing, or sometimes performing assistance to volunteers cleaning the river. It does not need to be fast; the speed limit on my favorite river is 10 knots. It does not need to have a small turning radius. The engine I would use has no reverse gear. Tight maneuvers would be performed by electric trolling motor, likely bow mounted.

I have not committed myself to this or any other design. I wanted to find out more about an unconventional hull that I was curious about so I started this thread hoping to hear from someone about their experiences with this boat. I wonder if any Happy Clams exist at all today.

I have heard about a vaguely similar modern equivalent (but more rounded, and much larger) hull called the "displacement glider" It has a deeper, narrower box keel running nearly the entire length of the bottom. It has very good fuel economy, but has a large turning radius, is difficult to steer in reverse and has high drag and poor handling and economy at speeds over the mid teens. It has gotten a lot of attention on other forums, implying some demand for the type.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...


×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.