One of the most frustrating, difficult, and least fun tasks associated with owning a boat is launching it and loading it back onto the trailer. Check out boat launch ramp failures on Youtube for some amusing and sometimes painful and expensive examples of problems. Boat trailer guide posts are an amazing aid, especially when positioning an empty trailer in the water and lining up the boat to load it onto the submerged trailer. They extend above the water to show you where the trailer is. They won't prevent some of the most dramatic launch failures like backing your truck underwater, but they do make positioning the trailer and loading the boat a whole lot easier. By the way, competent boaters will tell you to position the trailer so that only the rear 1/3 is in the water when you load the boat. Back the trailer all the way down until the bunk boards are wet, then pull it out until the rear 1/3 is still in the water. That not only makes it easier to see the trailer but when you run the boat up on the trailer it doesn't float off. I still find the trailer guides helpful in lining up my boat as I pilot it onto the trailer. Sometimes you can run the boat all the way onto the trailer but there will still be times you will need to use the winch to finish pulling it all the way on. And, of course, you need to use the winch to secure it before you attempt to pull the trailer out of the water.
We just pulled our Macgregor 25 sailboat out of the water for the winter. This was the first time I got to use my DIY boat trailer guide posts. The last time we pulled a boat out of the water (without guide posts) it was a real pain in the neck (or about 2' lower!). I had trouble seeing where the trailer was once it got submerged and had more trouble lining up the boat to load it for the same reason. The trailer ended up at a strange angle and I couldn't see it through the water to guide the boat correctly onto the bunk boards. Getting the boat loaded was a frustrating and time consuming ordeal that involved a lot of wading in cold, waist deep water and several tries both realigning the trailer and loading the boat.
I saw some commercial boat trailer guide posts on the Internet and it looked like a good solution to my problem. But they were fairly expensive, like around $100 or more plus installation! I thought about building my own out of PVC pipe and when I found DIY instructions on Youtube for doing exactly that it became a no-brainer. The total cost, for PVC pipe, fittings, and stainless steel hardware to attach them came to less than $25. It only took about a half an hour to build and install the guide posts.
I mounted mine to the back of the fenders and they pretty much fit right up against the sides of the boat once it is centered on the trailer. You might want to leave yourself a little more wiggle room if you can, but you don't want them sticking out too far. You don't want to exceed maximum vehicle width in your jurisdiction, which could be dangerous and could cause you to get a traffic ticket. Mine measure just 8', outside to outside, which is the maximum width in most jurisdictions. Since the beam of my Macgregor 25 is 7'9", the diameter of the guide posts pretty much puts them right against the rails so it just fits.
I was amazed at how much easier it was positioning the trailer and lining up the boat! I am surprised that I don't see guide posts on EVERY boat trailer! I'm sure if other boaters tried them they would agree. Turned out the whole process was so easy my wife and I loaded the boat onto the trailer without even getting our feet wet! Previously it had required at least one of us to wade about waist deep to guide the boat and crank the winch to load it onto the trailer. With the trailer correctly positioned and using the guide posts again to line up the boat, we were able to float the boat right onto the trailer, align it by hand from the dock, and winch it into place from the open tailgate on the truck.
Following the instructions I found online (Jon boat trailer guide (DIY less than $20). Like the video I used 1 1/4" Schedule 40 PVC pipe for my guide posts. A single 10' piece of pipe was enough to do both sides. I cut it in two, then cut 1' off each piece to mount them to the trailer. You'll need two 90° elbows to join the horizontal mounting pipe to the vertical guide posts. You should be able to drill holes in the fenders or fender brackets to bolt the horizontal mounting pipes on. In the video he installed short bolts through just one side of the horizontal mounting pipes, drilling holes large enough on the opposite side to get a socket through to tighten them. I used longer bolts and simply drilled and mounted them all the way through the pipe, figuring it would distribute the stress of torque from the tall guide posts and minimizes twisting. If you do it my way don't over tighten the bolts or you will distort and possible compromise the pipe, I put PVC caps on the tops of the guide posts. I glued the elbows to the horizontal mounting pipes but did not glue the guide posts into the elbows. Instead I drilled the pipes and the elbows and used stainless steel bolts and wing nuts to secure them so they could be removed if necessary. You can remove the somewhat ugly printing from the PVC to clean it up with a little dab of acetone so it doesn't have such a DIY look. I had some reflective arrow tape lying around I had picked up at Dollar
Tree and stuck a piece on the front and back at the top of each guide. I am quite pleased with the aesthetics as well as the incredible functionality of my DIY boat trailer guides. Frankly they work so well I would still use them even if they were really ugly!
With the guide posts sticking up out of the water it is easy to see where the empty trailer is going when backing it down the ramp. I was able to easily park the trailer right next to and perfectly parallel to the dock. It is also very easy to line the boat up with the trailer for easy loading. With the posts close to the beam of the boat they don't exceed maximum vehicle width and aren't in the way when I put my PVC pipe/tarp cover over the boat for the winter. All in all, a win-win situation! If your boat has less beam width you might have a little more wiggle room between the posts when you load the boat. Just be careful not to exceed the Federal maximum vehicle width of 96".
By the way, a useful trick I learned for loading my boat (as mentioned above) was to back the trailer all the way into the water to wet the bunk boards, then pull it out again until only about 1/3 was still in the water. That way, when you load the boat it will slide on easily but it won't float off the trailer. You should be able to drive the boat all the way onto the trailer, sliding along the wet bunk boards until the bow contacts the bow guide on the trailer. Then you just need to fasten the winch to the bow eye and you are ready to pull the boat out of the water and add any additional tie downs you need before hitting the road. Take care not to drive it onto the trailer too hard or too fast or you may damage the boat and/or the trailer. And remember, boats don't have brakes!
Guide on!