SHig's Pram Build Thread

[wjorg]

I think we need a new website just for Shigs pram building thread...

[michaeln]

I think we need a new website just for Shigs pram building thread...

http://www.analysisparalysis.org/shigpram.htm

[SHigSpeed]

http://www.analysisparalysis.org/shigpram.htm

Bwahahahaha! For sure... But the fun is in the process. I'll might never get the damn thing wet if I do end up finishing the project...

_SHig

[Blueracer]

Is that 200 pounds with the minimal gear you would have?

[SHigSpeed]

Is that 200 pounds with the minimal gear you would have?

Me sopping wet and 3 rods and lunch plus oars is probably 190.

_SHig

[fishngy]

Found this fine example in Monterey Bay this past week. It looks simple and not over analized. I bet if flies with the 5hp outboard! I also think no Cad program was used! Later, Bill

[michaeln]

You sure that isn't a motorized catbox?

[SHigSpeed]

Found this fine example in Monterey Bay this past week. It looks simple and not over analized. I bet if flies with the 5hp outboard! I also think no Cad program was used! Later, Bill

Awesome!! But I'll bet that weighs more than 50 lbs and I'd NEVER embarrass my car by putting that on top.

Love to see that milk carton on the open ocean.

_SHig

[SHigSpeed]

Kind of a big jump in design philosophy this time. I've been noticing that the revs I've been working on have had some "tortured" side panels near the bow. Basically, the sides SHOULD for ease of build be a simple contour, but due to the geometry there was a bit or twist or warp up at the bow tip.

One thing I've been contemplating for a while was to change up the floor layout a bit. To this point, I haven't changed the shape of the floor at all. Basically it was a curved sides all the way from stem to stern. I've been noticing on other prams I've been researching that there's curve in the center to create the bowed out shape, but the runs up to the ends are more straight. I think that the continued curve up to the bow is what caused the approach angle of the sides to be such that a twist was needed to mate to the bow plate. In order to have done away with the torture on my last model I would've had to have either tapered the bow plate narrower at the top than at the waterline edge (which would look odd) or stand the plate up more and reduce the angle at the fronts of the sides (which would kill a bit of the sporty profile and the anchor rope overhang).

SO, I modeled the fronts and back side edges of the floor as straight lines connected by one single arc between the two.

Result? No torture, maybe a TINY amount at the stern plate, but it could be assembly tolerances that induced it in my kirigami model.

Before:



Now:



Slightly less plan view area and therefore buoyancy, but it's probably negligible. A bit more reduction in front buoyancy vs. rear so I'd be less tempted to jump in the bow on a lark, but it may row easier as a result? It'll certainly be easier to build with more straight lines!

More photos:








I'll rework the 3D and flotation models next and gather the new areas for calculating materials. Not a huge difference, maybe a reduction of a couple percent of area is probably all.

I'll play with it in the tub and see if I find anything else to tweak (just kidding about the tub - DO NOT IMAGINE ME NAKED IN A TUB PLAYING WITH PAPER PRAMS!)

Punked!

Hahahhahahahaha...

_SHig