So, you borrowed your father-in-law's boat for your weekend at the cabin, or you bought a RV to take the family camping for this year's vacation. You got to where you were going and realized you now had to back up to get that trailer where you needed it. Maybe you hadn't anticipated this (but really, how did you expect to get that boat in the water?), or maybe you didn't think it would be a problem. How hard could it be? It's not like you need a special license to do it, and you've seen other guys at the boat launch do it, and they look like lesser men than your manly self. Right?
A few years ago, during a break between years at university, I got my truck license and went to work driving a big rig. What man hasn't wanted to get behind the wheel of one of those machines? They're big, they're noisy, you can see over everyone else, they can haul just about anything, and they have a horn to rival a locomotive. The part of the job I didn't count on when I started was the fact that I would be spending a large amount of my time in reverse while going around corners. I was not exactly what you'd call a natural at backing up. In fact, I almost lost that first job because I had such a hard time. With some coaching, and a lot of nervous practice, I eventually became quite good at it, and now I can back a trailer around corners and into little garage doors on the first shot.
Reading this article is not going to substitute for practice, but it should prepare you to start. The principles are the same whether you have a 53' tractor/trailer rig or a rented 8' U-Haul.
A Solid Approach
Backing a trailer into a specific spot at a specific angle is mostly in the set-up. Like most things, preparation is key.
First things first: roll down your windows. Driver's side and passenger's, and it doesn't matter if it is raining. If you have a passenger, it is best to kick them out before you even approach the actual boat launch, driveway, or campsite. You are probably going to want a spotter anyway, and they will either distract you or block your view if they stay in.
Forget about your rear view mirror, and don't turn around and try to look out the back window. Chances are, you can't see much over your trailer, and who cares what the front of that trailer is doing? You want to make sure your side mirrors are adjusted properly, because they are going to show you where the sides of your trailer are, allowing you to deduce what the back is doing. It may be more showy to do the big turn around and hug the back of the seat thing, but how much cooler to pull up and back that baby in without turning around? Appearances aside, it really is the proper way to do it. Proper mirror adjustment means when your rig is straight, your trailer is visible in about the inside third of your mirror. It is good to be able to see your trailer tires. This gives you a good view of where you are going and how you are doing.
Now you are almost ready to approach. For the sake of a consistent example, let’s say you are backing a camper into a campsite. It is coming up on your right-hand side. Stop short and get out of your truck. Go check for obvious obstacles that you will have to avoid. Don't forget to look up. Even if you have a straight shot to the back of the site, will you clear all the tree branches? This sounds like retentive health and safety advice, but backing over a stray chunk of firewood or someone's leftover wire roasting stick is going to be a rough start to your weekend. Try to make a mental map of where the picnic table is in relation to the fire pit and the back of the site. Pace off distances if you need to (you do know how wide your camper is, don't you?). Have your passenger(s) stand near major obstacles so they can shout if you are too close. You may not always be able to see them, but your windows are already rolled down, right?
The Right Set-up
The moment of truth is at hand. If you do this next part wrong, it doesn't matter much what you do after. Get it right, and you will look like a pro. It is the S-turn. You are in a forward gear with your campsite coming up on the right. Get that vehicle over to the right as far as you can without hitting something or rolling into the ditch and pull up alongside the entrance. How far along you go really depends on how long your rig is and what kind of hitch you have, but probably somewhere around when your truck bumper is coming up on the far end of the entrance, you want to swing out left. Don't go all the way. Before you drive into the left side ditch, crank it back to the right. This will make the smaller angle between the truck and trailer be on the right-hand side. Stop with your truck somewhere around midway between road shoulders. Congratulations, your trailer is ready and begging to be backed into the sweet spot.