Trex for Bunk Board Replacement

H

hardee

New member
I have an opportunity to replace may bunkboards and at least need to replace the carpets. I am considering using Trex board, for the water resistance properties. at the following link, I found the following statement about Trex.


http://www.c-brats.com/viewtopic.php?t= ... light=trex


Around here at Shasta Lake, they're using Trex, which about half wood chips and half recycled plastics for decking on docks.

However, the Trex doesn't have the structural strength to be used as joists, stringers, and piers, so metal or treated wood are still used for those parts.

Joe.
Click to expand...

I am wondering if anyone has used Trex for bunkboards, or has considered it and decided not to. If so, why not?

The trailer is a Pacific, galvanized steel, with 2 full length bunks and 2 shorter ones helping to support the stern.

Thanks in advance for any comments, This may be a time sensitive project, (Time with the boat off the trailer :)

Harvey
SleepyC
 
Harvey-

The water resistant properties of Trex make it great for this application, but you'd have to add a good number of extra support brackets or run another piece of lumber or metal along side them to keep them supported if you were going to use it flat or wide side up.

When they built our Trex deck in Fremont back a decade ago, I picked up a 2x6 Trex 20-footer. With the very heavy/dense board at my waist, the ends were nearly dragging 10 feet away from me on either end.

Left poorly supported on a trailer, the load would be right over the metal support brackets, as the rest of the Trex would bend away and give, leaving only the supported points to bear the load.

On the other hand, used on end (2" side up) and well supported, it would work out well.

Just my @ cents for a Sunday afternoon!

See ya' in Seattle in January!

Joe. :teeth :thup
 
Thanks Joe,

I have found all kinds of uses for decking etc, but even the Trex websites say it is not structural, so it might support itself and an occasional footstep, it does not appear to be the best choice for supporting a boat near 300 days a year. It may work on edge, but I don't want to sacrafice the launching depth it would require. I could use a 1x6 and lay it on top of the 2by's that are there but then I still have the old bunkboards and have increased the launch depth again.

May just wind up replacing with a good pressure treated 2 by 6 and new carpet.

Harvey
SleepyC
 
Harv,

I would not recommend Trex for bunk boards. It is much too flexible. There are other composite decking boards made in a hollow/I beam fashion that are much more rigid. You should be able to see an example of them at the Sequim Home Depot but I doubt if they will have any in stock.
 
We have used Trex on our docks in the past. The required spacing for longitudnals is 16" instad of 24 to 36". The boat is just too flexiable, as Joe and colobear say, for bunk boards.
 
I would use 2by6 cypruss wood with plastic tops from a trailer mfg.go look at my album Jennykatz its the last page of photo's and you can see them . I would not use trex or any other plastic wood product not enough support .
 
jennykatz":1znnidr3 said:
I would use 2by6 cypruss wood with plastic tops from a trailer mfg.go look at my album Jennykatz its the last page of photo's and you can see them . I would not use trex or any other plastic wood product not enough support .
Click to expand...
Jim,

Where did you get those plastic tops? I was thinking of adding something like those but was wondering if they scratch the hull.
 
My old trailer was a bear to load and unload and finally the bottom bunks rotted and I had to replace them. I ordered synthetic bunks (really about 1X4's - maybe a little thicker and faced them with teflon (slick) strips. A couple of trips later, I noticed the bunks sagging between the supports. These were made for trailer use and not plastic/wood composites. My boat wasn't heavy - 20' skiff/70 Suzuki so I have to attribute the sagging to the composite characteristics.
If faced with a similar task again, I would us cypress 2x6's as a minimum, GOOD quality carpeting to cover them and monel staples/ss carriage bolts.
I have made a firm pact with myself that my NEXT trailer is going to be matched to the boat or it's going to be a No Sale.
 
Mine came with my Continental alum trailer I dont know what brand I will have to look when Im down at the boat again . Just call up a trailer retailer its probably a Tie-down product .it fits right on top of a 2by6 cypruss board.No they dont scratch the hull mine is painted bottom .Its on my photo album I dont know how to put those pictures on a thread maybe someone can figure that out
 
King uses a product call Slick Bunks, or Glide Bunks, and it is available in 20' lengths that we stock and cut down for customers. $5 a foot. Slide over a standard sized 2 x 6.
 
My friend with another 26' CD rebuilt his bunks several years ago. It is obvious that Trex does not have any structural strength but he put Trex flat on top of his old bunks. Not a good result. After using it for a little while he discovered that the Trex was "chewing" his gel coat off of the bottom of the boat. It is very sticky when a fiberglass boat is on it.

I rebuilt my bunks this summer and used double 2x6 porch wood flat and put teflon strips on top. Works great. The teflon is a little pricey but it lasts forever. I used 1/2" thick teflon, counter sunk the holes and screwed it to the 2x6's using 2" stainless flathead wood screws every 6" in a staggering pattern.
 
OK, so the center 12 ft bunk boards are off the trailer, the carpet is off the boards and the preplan is off the wall. The plan was to unstaple the carpet, and then just replace the carpet. The staples ar all on the underside of the boards, (several hundred of them) and the boards are somewhat loos on the trailer, (bolts drawn down into the boards for countersinking), and the bolts are rusted up a bit. So it is easier to cut the carpet just above the bolt heads, and chisel around the hex head enough to get a socket over the head and get it to grip, then twist off the rusty nut and washer. Times 4 and the board is off. Turn it over and remove the gazillion staples, and ........

That's were I am at now, but need to see if I can find new bunk boards or need to use these. Not sure what kind of wood they are. It is a "Pacific" trailer with the two center 12ft bunks and the outboard 4 footers. (I am not going to do anything with the guide/side bunks at this time.) The trailer is a 2003, and the boat is stored on it year around. There was some wear showing to the wood at the forward inside corner edges, and some rust showing through the carpet over some of the bracket bolt heads.

Questions:
1. Should the bunk boards support, (extend aft of) the transom when the boat is on the trailer? (They did not before), or at least even with the most aft vertical edge of the transom.

2. Would there be any advantage to painting the bunk boards prior to covering with carpet? (to help them be more water resistant.)

3. If yes to #2, what type of paint/sealer should I paint them with?

4. What would be a "rough guess" as to how long the bunk boards or carpet should last, assuming it is parked outdoors at least 8 months a year. (It is rinsed off after both launch and retrieval in Salt Water.)

Thanks for all the good input so far and thanks again in advance for opinions here too :idea:

Harvey
SleepyC
 
I would not use anything except cypress. If cured well, painting would be Okay but more for esthetic reasons than durability. Bunks get soaked and the carpet gets soaked so think stainless steel for all attachments. Countersink cap screw or carriage bolt heads and put a dab of silicone spooky on them ONCE THEY ARE IN PLACE AND READY TO BE TIGHTENED. Find a friend with a compressor and a staple gun (not a hand stapler), pay the fiddler and get stainless or monel staples. Use good marine carpet that will drain water well.
If I'm going to re-do bunks, I try to follow the thinking of the folks who designed the trailer although I think some were designed by desert-dwelling orangatans who never saw water. Look at your boat and how it "wants" to sit on the trailer. It may take a few trips to find a lumber yard that stocks various sizes of cypress but it's worth the difference.
Good luck. :thup
 
Warren, I have and am. They are recommending "Purple Heart" a South American hardwood, comparable to teak in water repellency, and very hard, same hardness as hickory or hard rock maple. Not sure I can drive the staples into it. Alternative is stainless screws and washers, and a lot of pre-drilled holes.

Ain't life grand :?: :)

Harvey
SleepyC
 
Harvey,
Cypress might be available in the south but I doubt you could find it in the northwest. Purpleheart 2x6's would be very expensive. If it was me I would buy pressure treated fir from a lumber dealer where you can search through the stack. Look for straight boards with as few knots as possible. Usually you can get the best piece of wood by buying a longer than needed piece and cutting the length you need from the best part of the board. Use care handling and cutting pressure-treated wood because of the toxic chemicals it is treated with. Pressure-treated wood is extremely durable and should cost only about 1/3 the price of purpleheart.
 
Ken, Thanks for the ideas. You are right, no cypress in the area, Not even at Edinsaw, which specializes in exotic woods, with something like 90 varieties.

Pressure treated, at least what is available in our area, is hemlock. Subject to considerable warping when dunked and dried. So it dropped off my list of usable. Cedar, tight not or clear was an option too, but soft and subject to rot around the bolt holes, ends and staple holes. As mentioned, the Purple Heart would be good for submersion, but could not be stapled. (Should have considered contact cementing the carpet earlier in the planning stage...--I finally found the Monel staples, and bought my wife a really nice project stapler, since the monels would not fit in mine.)

Wound up with Meranti, a version of Mahogany. Straight, tight grain, no knots, and something more than "Pressure treated" price wise, but they are sure beautiful pieces of wood.

Harvey
SleepyC
 
Moved to Trailers and Towing forum at Harvey's request. Harvey is such an organized guy! Thanks, Harvey.
 
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