Raised on a farm, had to back up hay and grain wagons without mirrors long before I was legally able to drive on the road.

my boat is narrow enough that I can't see it behind the truck.

I fixed that found a peice of PVC strapped it to the back bottom of the trailer , saw where I could see it in both mirrors marked it and cut it so it was even and I could see it in both mirrors.

if I have a line going in a boat launch I can just put that PVC on the line and roll it right back very smooth for not being able to see the boat or wheel till it has gone too far off course.

the PVC is about 6 inches farther out than the wheel on each side.

Even more dangerous are wing dams and first time boaters. followed closely by stump fields.

If you want to learn how to back up practice in a big empty parking lot. Use your mirrors. Lots of options out there for nice big ones with various attachment devices if you need them. Those little stick on spot mirrors in the inside bottom corners help a bunch. After you get the angle on the trailer where you want it you need to follow it with your tow vehicle. Does take practice but once you start catching on you will wonder why it used to be hard.

ive been a MERCURY OUTBOARD dealer/repair for 35 years seen my share of inexperience too many times to count ,im still amazed that there's as few accidents on the water as there is

I could back a trailer almost into any space, the husband lets me do all the backing after he knocked the garage door down one time, lol.

Best lesson I've seen is put your hand at the bottom of the steering wheel, if you need the trailer to go right - move your hand and wheel to the right. If left move your hand and turn the wheel left from the bottom of the steering wheel.

Taught my boys to back before they could legally drive. If there was a speed competition I’m sure they’d place. They’ll fit it in some tight spots too. I won’t even watch them anymore, cause they scare me! As long as they got a couple inches clearance on either side they’re good to go.

Worked summers for nearly 40 years at a large lake/recreation area. In 2019, the estimate was just over 2.5 million visitor nights in a summer season. Blissfully retired now.
Park security was part of my duties. Had several calls a season like this…”You better get over here to Divers Bay because there are 30 fishing boats in line and one sailor sideways at the bottom of the ramp…he won’t make it through the hour.”
I hate to be prejudicial, but in my experience, many people love the image of sailing. They buy a sailboat with Crosby, Stills, Nash, and Young music in their heads…but the skill set is absent. Add a bit of “high class” arrogance, a great walleye bite, and things get nasty in a hurry.

No, I was absolutely terrible at it and knew it straight away. So I went and practiced somewhere other than the boat ramp. It was a large parking lot, well large for my community.
Do you show up for any kind of test without study or practice?

Novel idea, huh?