I'm Looking For Resources On How To Build...

Are there any hobby structural engineers out there?

I want to build out of wood a strong, but light weight hardtop for my new Beachcraft. I was contemplating copying the design/construction methods for a typical build-it-yourself airplane wing, but then I got to thinking... maybe someone has already figured this out? Anybody seen anytrhing like what I'm looking for?

There are no available grab rails for anyone walking atop the gunnel while heading to the bow, which forces my crew to stand on the berth cushions and use the bow hatch. The hardtop would serve for a support for some much needed handholds.

It should extend aft far enough to cover the oak cabinets, and overhang past the windshield to block the glare of the sun, and be wide enough to keep the rain off the owners. Rough dimensions would be about 8 feet long by 6 feet wide. I'd like to be able to stow my 10 foot inflatable tender up there (approx. 80 lbs.) as well.

I would love to be able to mount my radios and other electronics overhead, so that would be a consideration. Maybe a trumpet and some lights? Since I'm in the planning stages I figure it doesn't hurt to consider all possibilities, right? Of course when it's all said and done it would need to enhance the look of the boat while being extremly functional.

So if anyone knows of some plans, drawings, has pictures of what others have done, or just has some good working experience I'm all eyes and ears?

Doug

[Marty Loken (Norseboater)]

Hardtop for the Beachcraft?

Doug -

If it were my boat (hmmm...what a great idea!), I'd first see if it was possible to modify the stainless frame of your existing hardtop by running a tubular rail outside of the zipper-line that separates the top from the side panels. This might involve some resewing where the exterior grabrail-frame piece came through at the front and back...but it could be a far simpler and cheaper solution than designing a building a custom hardtop.

In considering hardtop designs, I'd first seek inspiration from powerboats of the 1920's and '30's. Boats were narrow-beamed back then, of course, so designers and builders were hyper-concerned about putting any extra weight aloft, for fear they'd increase the boats' already roll-prone nature.

The first semi-permanent 'hardtops' I've seen, in doing research on bygone boats, involved lightweight wooden battens running fore and aft, with canvas stretched overhead. (See photos below of a late 1920's Blanchard-built 20-foot outboard raised-deck cruiser, followed by a tiny pocket cruiser with cute fabric-and-batten top, and then a late 1920's Blanchard 36-foot Dreamboat with true hardtop you could walk on). While some of the early tops were obviously not designed to carry a heavy load, they looked sturdier than today's fabric-and-tubular tops...sort of an early hybrid between the soft top and true hardtop.

Hardtops made of wood were kept under control, weightwise, by using a framework of cedar or Sitka spruce (spruce being what they built early fabric-covered airplanes with), with thin cedar planking running fore-and-aft. The cedar was usually covered with canvas, giving you a light but strong hardtop. (Depending on the design, the cabintop cedar planking was either tongue-and-groove--if there weren't a lot of compound curves to deal with--or just regular planks laid alongside one another, perhaps with beveled edges as needed in different sections of the top.) The top we're restoring now for the 22-foot Lylecraft serves as one example of how they built them in the 1930's...except in this case the builder used strip-planked mahogany around the curved edges and an insert of thin Masonite-like sheeting in the flatter center section.

Basically, the early tops were like airplane wings--good analogy--but with the primary framing running side-to-side, not fore-and-aft, and battens in-between the frames to help support either a fabric top or lightweight wood outer skin.

Coming up with a hardtop that looks "right" and matches the rest of the Beachcraft design will be the challenge. Again, I'd start by seeing if it's possible to modify what you already have--a nice soft top--and work up from there.

- Marty

[Tim_Mattson]

Semi Hard top ideas

Doug ,
I saw a Chris craft on the canal yesterday that had a Bimini Frame that extended past the windshield area so water dripped well away from the cockpit.It looked pretty functional and had the handrails under the overhang for easy and safe passage to the bow.
Getting tall enough yet not too wide will take some mocking up.
If only 4` above the gunnel,then you`ll have to squat or turn sideways to get by and if taller ,it will reach a point where the wind will grab it when on the highway.
Break out the Duct tape,cardboard and scrap wood and go for the Red/Green Show approach to see what dimensions will take shape.A pair of
6` ladders would make a temp. base,then move to wood supports to check sightlines,Towing heigth,stand-up headroom,etc.
Once enclosed ,ventilation may be needed for those wet damp days.
I have an Alum Running board that would make a great overhead electronics base,cut to length ,then fab a locking door to secure the toys.
Come to think of it,I also have a hardtop a bit wide for a hull it is resting on......
Weight above waterline is bad weight......keep it light as Marty pointed out.
Tim M

[Skagitguy]

Doug, As you know i'am not a structural engineer but, I would just tie a line ( color keyed to the color of your new boat ) around your waist and the other end to the steering wheel. This way when you fall into the water the boat will not leave you behind it will just bang you against the hull for just a little bit. Oh and don't forget your PFD as that will save you. Glad to help out ! Very nice boat ! Your buddy,Chuck

[Sammamish1]

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