I totally get the why because we can, but a sithe though harder would sure build as much character as building some floating paddle boat of sorts, but not near as much fun.
KK4VKZ -SOTA-SUMMITS ON THE AIR-
SUPPORT LNT
Floating it across is very energy efficient, now designing the float craft and getting the mower on and off, well that's in the engineering. Also factor in the chance of catastrophic failure including loss of craft and mower and possible energy intensive recovery efforts.
Lashing the canoes together is pretty straightforward. Use a couple of 6ft or so 2x4 lasted to the thwarts. Deck it over with a few planks. Use ramps to get the mower up onto the canoes. The trick it getting the rig into and out of the water. Rig is surprisingly stable on the water since it's about as wide as it is tall. Carried an old gas powered fridge out of Upper Goose Pond cabin this way. Hardest part was getting it to the water.
Cosmo
Perhaps a fishing pontoon raft?
pontoon-08-3.jpg
I think I would try some PVC pipe with end fittings. Like 12 inches in Diameter or bigger with a 4x6 foot or so Piece of Plywood top. Make it with three or even 4 tubes underneath. Redneck Pontoon boat.
I hadn't checked the thread in a while. The mower weighs about 340 lbs and this stream crossing is the nearest road approach to about 7 miles of mowable trail.
It seems to me that building a bridge would be the best long term solution for that much mowing. Most of our trail gets mowed twice a year. That means four crossings of this stream with the mower each season. Several times we have floated all our tools and material down stream from the nearest road access.
Sled.
http://www.shappell.com/sleds.html
I know people that hunt in swamps that tow all their gear behind ATV thru shallow water on a sled.
I saw a guy one time, use one to get ATV across a creek. (back when ATVs were smaller 25 yrs ago)
210_Kodiak_XL-500.jpg
Assuming that you have access to 2 canoes (and a few 2x4's), this seems like the simplest (and the most stable, least likely-to fail catastrophically) solution to the problem. Trying to rig a zip-line that would hold a 350 lb weight WITHOUT developing a huge amount of sag is next-to-impossible unless you climb more than 70 feet above the waterline, and the size and weight of the cable (rope would stretch out too much) AT THAT HEIGHT ABOVE GRADE is clumsy, to say the least. Inner tubes can be punctured too easily, but a couple of canoes in good shape (lashed together with some 2x4's and maybe even a sheet of plywood across the 2x4's for a deck) seems to have the best chance to get the mower across. Perhaps 1 person guiding each corner, and a "bull-rope" tied off on each bank and attached to the "raft" fore or aft...just in case.... Make sure that your people are NOT directly downstream of the raft, in case it starts to swing around.
Life isn't about waiting for the storm to pass - it's about learning how to dance in the rain!
Shed looks interesting as the sloped end would appear to minimize problems of loading and unloading that may inhibit actual realization of the canoe idea. It looks like the Kodiak XL would displace about 0.4 m^3 = 400 L which is 400 kg of water. Since the rig is 340 lb and sled is 30 lb so ~400 lb with neutral density fluid and Earth gravity and 2.2 lb/kg it's possible the assemblage might actually float with a safety factor of ~2 if my late night reasoning is correct. Or until a wave or tip swamps it.
My colleague pointed out another aspect: "If the plan is to mow all the way from where we parked the vehicles last year to Nickel Falls and back it doesn't matter where we start as we will still have the same distance to cover."
Build large pontoons from beer cans and duct tape. Tape the Dr to the top and find a buddy that is drunk enough to sit on top and row. By the time the pontoons are complete, you can bet that someone will volunteer.