I have a Shore'Lander trailer that has rollers on it -- I have found recently that when I am putting the boat on to the trailer (I load it by hand, meaning I use ropes to get it up to the initial rollers and then attach the winch strap and then winch the boat onto the trailer) it is ending up about three/four inches too far to one side of the trailer (I will try and take a picture and post it) --- it seems to start off straight when I am cranking the winch, yet gradually it lists to one side --- I can trailer it and I do not think it is a safety issue but I would like the boat to sit straight/even on the trailer --- The rollers have good "tread" on them --- Has anyone else experienced this ? What did you do to correct it ? Do the rollers become mis-aligned over time ? (the trailer is a 1993 and I bought it three years ago so I am not sure of it's full history) Thank you 

In thinking about this, you may be right that the rollers can get out of alignment.

I have never experienced this myself (always had bunk trailers), but I would say it can absolutely occur.

 

I'm not sure how you'd be able to diagnose exactly which roller(s) are out of whack though.  That seems difficult.  I'd start by taking a close look at them when the boat is not on the trailer.

 

While it may not seem like a big issue at this time, in the long run it could have significant issues.  More weight on one side could cause uneven tire tread, which could lead to a serious problem.

 

I have seen misaligned roller ruin hulls.  If one is too high it can put a hook in the hull or a bow in them if too low.  A hook slows a boat down, a bow cause one to be bad about wanting to porpoise.

It's common to see the front or rear roller get worn out, causing the center to put too much pressure in the center of the hull.

When the boat properly positioned on the trailer, should be sitting on the front and back rollers, then the center roller/rollers are adjusted so they are firmly against the hull put not pressing up on it.  They just support the center to keep it from bowing down.

1st try backing your trailer down a foot or so until the boat  just begins to float then snug up to the front roller. When you pull the trailer out check to see if still tilted.

If it is the back roller on the tilted side needs to be lower until level.

As noted above the center rollers shouldn’t be holding up the boat.

Sometime your wench stand has moved forward, check where the rear roller is under the stern, should be just under the rear.

Aluminum boats are forgiving regarding hooks in bottom, but bunks are safer to use in that regard. 
Also the extra wide roller attachment is well worth it.

Tom

@Way2slow  @WRB-2.0 - thank you for the feedback - I will try putting the trailer in more shallow (ie, not as deep in to the water) - then attach the winch strap and start to winch it on to the first set of rollers and see how it is aligned on them - then maybe back in a bit further and crank the winch again and see how it aligns on the 2nd set of rollers - then do the same for the center roller - I can also inspect the trailer at the dock area (with the boat off the trailer) to see if the hinges on the rollers are working properly (they seem to be but I will take a closer look) - I will need to try and find a time/dock that is not busy - lastly I will look to take some pictures as that might help as well - thank you again for your time and feedback !

You might want to take and record some measurements of the different rollers.

Well, if you REALLY want to do it right, do a complete and proper setup of the boat on the trailer, starting with setting the tongue weight to the recommended 10% - 15% of total tow weight.  This is critical on any trailer for proper towing but something most seem to never do.

To get the total tow weight a lot of truck stops have scales you can pay to use.  With your normal fishing load in the boat and weigh it.  Do this by parking it on the scales, disconnect from it and move the vehicle off to get the weight, or weigh the vehicle with boat, then weigh just the vehicle and subtract that from the vehicle and boat weight.  

It sounds like you have a smaller size boat so a set of bathroom scales will work just fine by placing them under the trailer jack.  If your total rig weight was 800 pounds, you want 80 to 120 pounds on the scale.  

Now come the tricky part and hope you trailer is the proper size for the boat because you will need to move the wench stand with the front stop on it so you can move the boat forward or back on the trailer to get the proper tongue weight.  "IF" the trailer is not properly sized, doing this may not be possible without repositioning stuff in the boat.  You don't want to move the boat forward enough that it comes off the back roller or the motor hits the trailer with it down.  You also don't want it too far back that the back roller is a couple of feet up from the transom.  Once you have it positioned for the proper tongue weight, the set the rollers so they are providing the proper support.

 

If the tailer does not allow proper positioning of the boat because it's the wrong size, then I would look at adding bunk boards.