Pedestal Plastic?

[adkSara]

Pedestal Plastic?
by dhj
I'm trying to outfit a WS Forplay. I don't want to drill holes in the plastic or try to glue directly to the hull. I was considering forming a plastic sheet to fit in the cockpit and line up with existing seat holes. Does anyone have insight into the ideal type of plastic to use? I'm not an engineer so I don't know how to interpret tensile strength, impact strength, flexural strength, etc. Does anyone know what kind of plastic the dagger pedestal is made from? What about any lighter plastics that might have suitable mechanical properties?

Here are some that I've looked at:
Polyethylene (HD?, LD?)
Polypropylene
Polyvinylchloride (PVC)

Here is a good comparison reference I've found:
http://www.machinist-materials.com/comp ... astics.htm

Also, it would be good if the easily moldable temperature is less than the polyethylene used for WaveSport kayaks (HD?, LD?). That way the strip of plastic against the hull could be formed exactly to the hull for support.

Any input would be appreciated.

--David


Posted on Oct 24, 2002, 2:59 PM

plastics...
by Scott B.
I'm no engineer either, except in the "shade tree" sense.

The factory pedestals (Dagger, Perception, Noah) I've seen were all made from polyethylene, if that counts for anything. I've used ABS (about 1/16" thick) in outfitting boats in a manner similar to what you describe. I've also seen a couple of boats set up using fiberglass in the same way.

I'd think anything stiff enough would do - I don't think you need to heat form it. When you take the sheet of plastic and press it into the boat, securing the sides with screws/bolts, it's going to naturally conform to the shape of the boat - the arched cross section should be pretty stiff, too. If you are concerned about strength, use a thicker sheet or add a structural member running from bow to stern (that will add more strength than thickening the sheet).

Your choice of material might also be shaped by how you want to attach things to it - contact cement for attaching padding/pedestal should work with any plastic, but trying to anchor thigh straps with an adhesive might be trickier. You could always use a mechanical system for that, though (ie bolt to a rigid member running front to back).

Check out the Team ETC system (link at www.cboats.net) - they use a similar approach, I think, and have a lot of details worked out.

Scott




Posted on Oct 25, 2002, 6:19 AM

not just to the hull?
by James
Why not just stick it all to the hull? If you convert back to K1 the seat covers most of the glue marks. Another option, I've used an old aluminum paddle shaft lengthwise in the boat into the front and rear pillars. My saddle is attached only to this shaft, bulkhead is pressure fit, no glue. Both can be adjusted back and forward for trim or bigger and smaller paddlers. Thighstraps go around the paddle shaft.

wait, what am I thinking? We're all C-boaters, we're looking for challenges in outfitting, paddling etc etc. Get on with this plastic sheet business and let us know how it turns out.


Posted on Oct 25, 2002, 6:57 AM

well...
by Scott B.
I incorporate the plastic sheet / platform idea beacause it is cleaner, easily adjusted, and can be quickly moved to another boat. The real reason though, is that I am cursed with a tendency to overengineer Soooo, my boat is a bit heavier than yours. But then again, I was able to turn my old Ultra-Clean back into a kayak (for sale) and convert my new Score (excepting a few subsequent tweaks) in about hour and a half - 30 minutes of which were spent in the hardware store looking for a replacement screw.

Sounds like your set up is a clever solution - can you send or post pics? I have a new boat I'm setting up that will never be converted back to a kayak (no seat!)

Scott


Posted on Oct 26, 2002, 4:35 AM

Vinyl fence post
by Randy
It is not a moldable plastic sheet, but it did the job...

From a previous posting here, I took the hardware-store-plastic-fence-post idea and used it in my recent Redline conversion. I used two aluminum straps, bent to the cross-wise shape of the boat, to fasten the plastic rail (the 'fence post') down the middle of the cockpit. The straps are fastened to the boat with the same fasteners and holes that the kayak outfitting used. The rail is bolted to the straps with new fasteners that don't touch the boat.

Foam and strap outfitting was a breeze using the rail as a base. I made mine fully adjustable.

It seems bomb-proof so far. I believe it is lighter than the factory rig.

Photos and details provided upon request.

Randy


Posted on Oct 25, 2002, 5:39 PM

Pics of fence post conversion
by Scott
Could you post some pics of this please


Posted on Oct 26, 2002, 8:50 AM