They work great and have their place, but the easiest way to get them around here is to just set where they’re going already. Just a trap and maybe a stand required. They’re good for trapping off the road, but if you gotta haul your stuff in, you’ll be sweating for some easy beaver. They’ll catch on to them pretty fast too.
Here’s a template you can fool around with….
Keep in mind that they’ll crawl over from the back and sides. Some guys build a big blocker wall and it ends up looking like a fortress out of Game of Thrones…..lol
I made a few with scrap 2x4 and some 1.5” blue insulation sandwiched in the 21” hatched areas.

The nice thing about floats is that they aren't affected by varying water levels. I tried them and found often the beaver instead of going through the front where the trap was, they would go over the side avoiding the trap. A 220 is too small for a large beaver.

Like this?built these couple years ago,kinda fun to make,saw the pattern on here somewhere,mn man maybe

Great for spring (openWater) here used Backbreaker/ wilsons green saved castor on floats shown above no issues with rising, falling water I prefer cutting a trench in brush, cattails willows ect. with snips stick in my float facing down current the moving water takes scent that way and beavers follow that use a T style trigger underwater
Ived used 4-6 inch dry spruce and cedar posts and screwed on pieces of rubber belting that slide thru the springs for holders
Whatever you do try your prototype and add foam strips to get a good float you dont want your trap to low so a beav crawls over it Yes i set shallow and wear kneeboots

There is fence wire underneath it so they can’t crawl under it,and yes you have to play with them so they float right ,and make sure you’re trap is on it when you test it

I have to ask, if they ones using floats use are the same ones that use disposable stakes when land trapping so they don't have to carry rebar. I would not want to carry one far.

100% Great for water fluctuations.

That’s straight outta Lord Of The Rings……..lol but probably effective!

yes, you don't want to carry them far, I like to tuck them into the brush or cattails, so they only have one way to come into the float

True but a 280 would work.

Those look pretty much like my set ups 330-T. There’s a guy in central Manitoba that’s fooled around with floats for 20-30yrs or so. He’s built them out of just about everything from logs in the bush to the thin plastic like the stuff that covers boards on hockey rinks. He uses them because of the crazy water fluctuations along the Saskatchewan River and its feeders.
The dimensions will get a guy in the ball park, and you can tweak them as you’re putting them together. Super easy, and if the things a big heavy beast and it’s possible, just hide it somewhere nearby at a spot that you’ll use it often.
I think I’ll dabble with pallet board this spring. They’ll lay pretty level, but would be ok for getting tucked into the bull rushes & stuff. Big culverts with current is where I usually use them. In spring they hammer the travellers, but resident beaver catch on to them real quick.

Shakes, I also use them in culvert with current mainly. They don't crawl over the sides or dive under in steady current where I've set

They usually come up the current to investigate, but I still get them leaving the set sometimes. I don’t have any real blocking though.