Recommend boat trailer bunk material that won't scratch fiberglass (gelcoat)
- Thread starter BCenic
- Start date
Steve Sanford
Well-known member
Good morning~
I have been somewhat intrigued by your question - mostly because I had never thought of bunk carpeting as a source of scratches in hulls. I imagine most of us have replaced the carpet when it wears through - but otherwise no hull damage to report.
Nevertheless, I did go to Ultimate Bunk Boards.com to explore and learn. I had been totally ignorant of the world of "alternate bunk materials". I will be replacing a pair of bunks on a small trailer soon so was especially curious. I watched the installation video.
I was very surprised that any bunk boards would fail after just 2 years. The boards look like treated 2x4s but had rotted. The "mushrooms" were evident on the bottom of each bunk and the board itself snapped easily. More important, though, was seeing that the board had been wrapped/encased in the carpeting. Even with treated lumber, this seems a poor practice. Bunks are meant to be immersed and so moisture needs to be able to escape when the trailer is back on terra firma. Every bunk I have seen is open on the bottom.
I replaced the carpet on a customer's trailer a couple of years ago. I did not replace the wood but did include a few upgrades: galvanized nuts, bolts and washers fastened with Anti-Seize; brackets set in caulk (to keep out trapped moisture); long s/s staples (with pneumatic stapler).
When making new bunks, I look for relatively clear treated lumber. I mostly have used 2x4s but have also used 5/4 decking as it is more flexible and so can conform to a round hull (as in a traditional Sneakbox). I also round the upper edges (including the ends) of the boards with a half-inch radius router bit so the edges are less subject to wear.
Thanks for my Continuing Education!
All the best,
SJS
HDPE bunk board, OH HELL NO. Been there done that. I got my hands on HDPE in 2x4 form and made bunk boards from it thinking it would be perfect. Smooth, rot proof, and low friction. A TOTAL DISASTER. They were so slick you had to be very careful when you disconnected the winch strap otherwise the boat was going to launch itself onto the concrete. They also resulted in a very worn hull. I found it counterintuitive that something so slick resulted in wear but let me tell you something, it was like 220 grit sandpaper. I think what was happening is any sand or dirt in the water got between the bunk and the hull and stayed there abrading away every mile down the road. They also didn't hold a load very well and tended to put all the weight where the brackets were. I think a carpeted 2x4 is still the best overall bunk set up I've found. Carpet seems to keep dirt particles off the hull and wood 2x4s spread the load over the length of the bunk. Use a treated 2x4, a thick carpet, and stainless steel screws and they will give you years of trouble free service.
I agree, the plastic bunks have several drawbacks when used naked. I am tempted, however, to use HDPE and cover it with carpet. I'm getting too old to be replacing trailer bunks every year.
Eric Johnson
New member
Carpet itself generally will protect gelcoat.
The issue with carpeted bunks and gelcoat scratching mostly occurs when sand gets into the carpet and then it is no longer protective carpet - but is now sandpaper for your gelcoat.
Sand will often get into the carpet at a boat ramp with boats launching or lifting and the engines mixing sand and water together
Some of that sand/mud/grit landing on the carpeted bunks
This can also happen with material - as Eric P has pointed out above - other than carpet but the fibers in carpet seem to hold onto the sand more
Possibly wash out carpet occasionally when boat is off trailer
The issue with carpeted bunks and gelcoat scratching mostly occurs when sand gets into the carpet and then it is no longer protective carpet - but is now sandpaper for your gelcoat.
Sand will often get into the carpet at a boat ramp with boats launching or lifting and the engines mixing sand and water together
Some of that sand/mud/grit landing on the carpeted bunks
This can also happen with material - as Eric P has pointed out above - other than carpet but the fibers in carpet seem to hold onto the sand more
Possibly wash out carpet occasionally when boat is off trailer