I've got some fast rising floodwaters and a non-tilt trailer under a 16X48 alweld Jon boat.
I have to try and load/unload on a flat flooded roadway (about 6 inches deep water+ ) but my boat sits on carpeted trailer bunks. They leave the bottom of the boat transom 2 feet off the roadway to start out {great for hauling down road,sucks loading/unloading in the flood}
(4.80X12 tires don't help my height either.)
I can put bunk rollers on, or bunk glides with silicone spray, but my trailer height still sucks with no ramping angle.
Any tips to help would sure be appreciated!

During hurricane floods I launch in a ditch to give it some slope. Just watch your trailer lights I ripped both of mine off doing this.

put rollers and an electric winch. rig pullys 2 rear of trailer for off loading and use strait off winch for loading.

Orrrrr..... Unhook your trailer from truck and winch your trailer underneath your boat. I do this all the time with mine after working on trailer bunks.

"is this something your needing done like this instant?"

It is rising way faster than I have seen it in decades! Heading for 554,000 cubic feet per second flow here on the Upper Miss.
If more rain this week, it will pump Illinois Rv. ,Ohio River, Missouri River and Mississippi river all up beyond normal floods and could start showing wicked rise downstream from Chester, Il to Vicksburg, Miss. next week.

Gator glide will be high on the list after the water recedes, so will the electric winch and rollers, but this current dilemma is because I got a new trailer and the yard flooded and sealed off the roads in less than 2 days. Now it's 2-1/2 miles to get to the old house by boat and getting farther every day. 32 degrees weird temp in mornings is double wammy.

da go get'er, I will try that but the current and high winds are pushing sideways on the road water and it makes it tough to retrieve if the trailer floats/wanders.
I normally ditch drop my old 14X36 w/longtail (led lights high up on the post style guides) but the rise in water is so fast it's a bitch when you return to the truck. The old 14X36 is just too small for this flood so I'm hoping to switch to the 16X48.
Todays nearby examples --->
and

Well its off to bed now, dreams of lower water tomorrow ..............

I know it's already been said, but Gator Glide! It's going to be more than enough to accomplish what you're looking for, especially on a boat that small. My heavy ass 19.5 x 48 boat with 3/16 bottom, 35 SD, and all kinds of heavy bullshit inside is a cinch to slide off the dry carpeted bunks on ramps with almost no slope. Try that first before you spend three times as much on an electric winch and rollers.

Secondly, if the water is still rising, what's the problem? Give it a little time, and you can float it off...

Unhook your trailer from your truck tip the tongue up n slide boat off if its balanced even. That or find a ditch like was said.

when putting my boat in our lake I had a similar problem when the water was low. the bunks never touched water, had to back so far down the boat ramp that the boat and trailer were no longer on a slope.
soo what i did was un hook boat from winch,
tie boat line to back of trailer,
put truck in 4x4,
back down ramp fast then slam breaks,
but truck in gear and launch forward a couple feet, then roll back,
repeat.

having Gator Glide would be best option

Couldn't you tie the back end of the boat to something and then pull vehicle and trailer away. Then find the deepest ditch, pothole or whatever to reload and winch it back on. Once you get it half way winched on move your truck to a level spot it will be a lot easier to crank the rest of the way

Thanks for all the help!
Tying off to a tree (or other object ) and driving away could work, but trees behind the boat are way deeper in the water, thus requiring me to wade real deep in swift current of unknown depth to hook up a drag line. Loading the boat back on the trailer would still be a hassle though.

Ditch dropping can work, if you can find the side of the road and not put your truck into the ditch

Best solution so far --- I saw some fellow river folks use roller bunks (I used oily cooking spray on my bunk carpets but plan on ordering some of these ---> }.
THEN; They rounded off the top edges of the rear bunk boards, THEN added some extra lengths to the existing 2X4 bunks by attaching a carriage bolt & wing nut to pivot a 5' foot longer 2x4 boards that touch the ground at an angle. Makes a little ramp all the way from the roadbed to the trailer. Some bunk slicks ( on those 2X4 "ramps" would make it much easier to load and unload.

Lowering the winch to make a "straight winch" and some extra pulleys to grab the boat from the transom end (using these ?? ----> ) might be an experiment I try when (if) these flooded waters recede. Definitely will order some Gator Glide too!

40 degree water, 40 mph winds ,and 2 inch rainfalls knocks the frickin' fun right out of this adventure.

Finally, some unsolicited advice to some of you younger mud pups --- keep your good friends and family close, and makes lots more of them as you get older.... it sure helps when you need them someday....and they usually only put up with this kinda disaster stuff once or twice before you wear em' out (or they wander off to the local tavern)

I still think you're WAAAYYYYYY over thinking all of this...

Try the Gator Glide first. Trust me.

Tie it to a tree. All of our lakes have been low for the last 3 years. The only way we can get my boat off the trailer on a few lakes here is by tying a line from a dock cleet to the back of my boat and pulling the trailer out from underneath it. My bunkers are always completely out the water. Just jump it back on the trailer when loading up, need a good winch on your trailer though.