Potter 19 trailer bunker replacement

Started by gever, Aug 31, 2024, 05:06 PM

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gever

Hi Folks,
just recently acquired a used Potter 19 and I'm suddenly scrutinizing the trailer bunkers (or skids) that the boat rests on. The previous owner replaced the factory bunkers with plastic 2x6 (explained to me as a way to not scratch up the bottom of the boat).

It looks to me like the plastic 2x6 is not rigid enough and the trailer frames are putting more pressure on a smaller area as a result (and I think he added some 2x4 to try and stiffen them up). Tried to capture it in the photos.

Should I be replacing these the next time I have the boat in the water? If so, what would you recommend?

Thanks! Hope to meet y'all at the next event.

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Bud

I purchased 2x6 pressure-treated boards and covered them with indoor/outdoor carpet.

Charles Brennan

#2
Gever, IMHO, right idea, wrong implementation.
I've had my sailboat, a Windrose 18, Urchin over 45 years.  I used to have pressure treated bunks with carpeting and used to have two problems.
1) The bunk would still rot out after a half-dozen years.
2) The carpet retains moisture and the trapped moisture eventually makes blisters in the gel-coat on the hull.
Everybody thinks that as soon as the water runs off, you are OK.  They don't consider things like rain water, running down the hull and soaking into the carpeting, even when the boat is just sitting there in the driveway.

My solution to problem 1, was to use a non-wooden bunk, so now it CAN'T rot.
They are called Trex™ and are used for decking and available from most big box stores.

https://www.trex.com/products/decking/

A single plank (like in your pic) is far too flexible for supporting an 18 or 19 foot hull.
The Trex planks typically come in 12 foot and 16 foot lengths.
Since I needed 8 feet for a bunk length, I bought 2) 16 foot planks.
What I did was to cut a 16 foot plank in half and take the two planks and screw them together back-to-back and then install them.
The other problem with the DPO's implementation was trying to support only from the "sag" instead of from the entire length of the plank.  There will still be play, but you want that, so the hull is cradled more evenly.
My original attempt was with a single plank thickness, and quickly saw that I needed a double thickness of planking, for the support I desired.

The solution to problem 2 was to use HDPE strips screwed to the planks.
Taco Marine sells a product called Glyde Slicks which are 2 feet long.

https://tacomarine.com/dockside-accessories-p06-06?srsltid=AfmBOopMBUl6tXra2LQiAtdyC4cCfmnjDmX2WkE7YK9jhFAgKVf2LWRd

I got several of the kits and screwed them down the length of my planks as shown below:
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Three columns of Glyde Slicks is really overkill, but the reason I did so, was because when the hull is coming onto the trailer, it can rub on the side of the planks until all the way up on the trailer. This way, the hull is always rubbing against a Glyde Slick and not a plank.

Another implementation detail:
I turned the original plank upside-down and mounted it to the support brackets. Then I placed the top plank over the bottom plank and then put the hull back on the two planks and screwed the planks together from underneath.  This helps maintain the hull curve.
You can just see the slight (un-loaded) curvature in the pic below:
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Here's a close up, which if you zoom in a little more will show the two planks screwed together.
You'll notice they are not lined up.  This is because there are grooves in the bottom of the planking and I off-set them, to get the most flush fit possible.
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The planks and slicks you are looking at are about 25 years old, so they have held up far better than any pressure treated bunks and carpet solution.
I no longer get hull blisters, since water runs off immediately.
I don't get scratches on the paint on the hull, either.

******* WARNING*******
They are VERY slippery.
They used to come with a sticker reminding you not to disconnect  your winch cable until ready to launch.
I never disconnect my winch cable until my hull is over water.

I once watched a guy at the Hollywood Marina in south Florida, backing up a 25 foot sports fisherman and his buddy shouted something to him and he instinctively hit his brakes and dumped the boat right onto the asphalt and put his lower unit through the engine compartment.

On the plus side, it is extremely easy for me to launch my boat.

Hope this helps,
Charles Brennan

gever

Charles (and Bud),
Thanks for all of the details, I really appreciate the way you've thought it through. I think that I'll put it on (carpeted) 2x6 that I have left over when I take the boat out tomorrow, and then I'll order some Glyde sticks and copy your full plan when I have all the parts.