I’d have to dig way back into photo albums that are in storage. I’ll describe it to you as best as I am able:
First, I’ve done this twice. Once for a cradle to ship the boat on a container ship pallet. The cradle was 20 ft long and had 4 stations on each side for pad pillars. The pillars were angled inwards about 15 degrees and were made of 3" water pipe, welded to the cradle frame. Each pillar was fitted with a 2.5" water pipe “telescoping” extension. The end of each extension was fitted with a 12" square pivoting pad of 3/4" plywood covered with carpet. With the boat keel sitting on the cradle base, we adjusted each pad to support the hull, then drilled 3/4" holes to fit 3/4" bolts through each pillar support and telescoping extension. Actually, we pre-drilled some holes on a couple of pillars, spaced regularly about 2" apart, so that we could quickly adjust those 2 pillars and support the boat laterally when first lowered onto the cradle. The positions of those holes were a guess based on some crude measurements of the transom. The cradle was positioned on a container ship pallet, the boat lowered onto the cradle, the pillars adjusted, and the boat strapped to the pallet. With its wanderings, the container ship traveled over 20,000 miles on its way from Pago Pago to Seattle, loaded and offloaded several times, without incident.
Some years later, I modified a power boat trailer to transport the boat as follows: I added a 3rd axle and beefed up the frame. I modified modified 6 of these: Heavy Duty Under Hoist Support Jack Stand - Walmart.com
And mounted them so that they leaned inward 15 degrees. Actually, I bought 6 of them from Harbor Freight for about the price of one of these from Walmart, but that was years ago and I can’t find anything comparable at HF now.) I added carpet covered pads to the top of each. Then, I positioned the trailer alongside a floating dock at a boat ramp at low tide. At high tide, I floated the boat onto the trailer. As the tide went out, I adjusted the pillars to support the boat. At low tide, I hauled the boat to my property here on Whidbey Island.
20 ft = 240" cradle with 4 pillars each side, evenly spaced, so 80". You can argue that it makes more sense to space them closer together aft. However, we simply positioned the boat so that the aft-most pillars were just fwd of the transom, which accomplishes the same thing, I think. Approximately 7.5 ft of the hull was overhanging the front of the cradle.
I cut down the adjustable stands on one side from their original 60", so that they leaned in 15 degrees. I welded tabs on each “foot”, again at 15 degree angle, so that each stand sat flat on trailer frame members. I bolted each to the trailer with 3/8" bolts. When the refit was finished, I relaunched the boat and sold the trailer.
Someone on this forum was saying they had made a CAD model of a Hess hull. Maybe it could be the basis for a solid model design of a trailer. (I am not volunteering, although I know how to do it.)
Good point. I’m thinking that the cradle was 8 feet wide, to fit to the pallet. Going up about 5 feet at a 15° angle, that would put the distance between pads at about.70 inches apart. P
That sort of matches what I was hoping. We’ve fabricated a steel cradle and now have to cut the post heights. I really only get one shot at it to get it correct because when the crane comes to take out all of the clubs boats, if it’s wrong, I’m in trouble! We have purchased scaffolding base plates that can be angled and adjusted for height. They slide in upside down to the square 2’" welded feet. I’ve cut them to 58" (angled so at 60" height they will be about 70" apart.). I’m now thinking that they maybe should be a bit shorter, just in case. The base plates can be screwed out a fair bit if needed.
The cradle bolts to a three axle heavy duty trailer. So now my only other calculation is to figure out the fore/aft centre of gravity in order to get the correct tongue weight.