2015 AI: PVC Bunks w/Only 2 Supporting Points?

After less than a half-dozen outings carrying the main hull on the trailer upside-down and flipping it over, unloading it, and then assembling the akas/amas.....

As expected, bunks are calling out to me....-)

Looks like 8' just about covers the "flat" of the hull. i.e. from where the scoop begins in the bow to where the rocker begins in the stern.

I have 48" between crossbars with the option of purchasing a third crossbar to put between the original 2.

I am thinking that maybe with the right diameter PVC and a wood or plywood stringer/internal i-beam inside the PVC (analogous to FusionEng's broomsticks inside his 1/5" PVC bunks) the stuff might be stiff enough to get away with just two crossbars and, even if a third crossbar is needed, stiff enough the handle the 2' of overhang at each end.

Am I even close?

If so, 2" PVC? ...... 1.5" PVC?..... maybe even 3" PVC ?

_________________
2015 AI in "Dune" - "The Grey Pig"
2017 Trailex 450 Trailer
Pre-September 2015 cradles
(anybody want to buy a slightly-used AI SpinKit?)
eMail: [email protected]

I'm not sure what the size of my PVC pipe (don't remember the size), but whatever size it is, a standard broom stck handle fits inside nicely (I was thinking it was 1 1/4 class 40 PVc).
On my harbor freight trailer it's about 2.5 feet between each crossbar. My pvc is about 8 ft long and it sticks out past the back of the trailer about a foot (this works out really well for aligning the boat in the wind, when pulling on the trailer). Up at the front of the pvc pipes I just have a brace (a piece of 1/4 x1" by around 13" long the connects the two Pvc's together and holds them on the 11" centers. The alum just sits on the tongue extension (should have probably bolted it to the tungue extension but I didn't). The broom sticks are incredibly strong. I've had the same setup now for a couple years and it's holding up well. The AMA's just sit on the outer frame rails of the trailer. I took some pipe insulation foam (Kieths roid foam) and taped it down to the outer frame rail in two places to act as a padded landing pad the AMA's. I just wrapped the electrical tape around the frame like you would bicycle handlebars with the roid padding under it. That black electrical tape is amazing stuff and holds up for years.
That's what I have and it's worked out pretty good. As the steel parts rust out I just replace them one at a time with 2 inch angle aluminum. There are 3 cross bars I've replaced one in two yrs, will likely replace the second one next year. It takes about 30 minutes to remove a cross bar and replace it with alum (as needed only). Obviously the trailer looks like crap, but I don't care about that as long as it works and is reliable.
FE

You may find that it is easier to add crossbars than to stiffen the pvc. I have seen people use 4" over larger spans but every additional inch of diameter is another inch you have to lift the stern when loading. I looked at all sizes and settled on 1 1/2" but I have it well supported. You don't want the pvc to sag under the weight of the boat, that would be like storing it on two cradles.


Chris