these are some pics of a trailer rinsing system i installed on my trailer. most trailer experts say the most damage is done while you leave your tailer at the ramp for 8-10 hours with salt water drying on it.
bladder tank which holds 5-6 gallons
pipe running down the frame
flex pipe running behind wheels with sprays attached
open the valve and spray after you launch
go fishing and don't worry about your trailer