Customizing a trailer for CP 23, a "situation" re bunks has arisen

[BruceW]

I bought a double axle trailer which has been under a powerboat.

What I did was:

a. bought some uprights, connection hardware, a keelboard & associated mounting hardware, boards to help thread the keel, etc.

b. first time, a couple years ago, the distance between the front cross brace and the middle revealed itself to be so long that the keelboard bowed. I braced that with some angle iron going longitudinally, and went back to work.

c. I had to replace all the springs, and took my time getting around to it. Then, new hubs, wheels, and tires.

d. This spring, I realized that my uprights were no longer the right height, because by bracing the keelboard, I kept the boat from lowering to touch the bunk. That is, they weren't really the right height after all.

Do yawl see the missing variable that I never thought of until now?

Well, I never realized the length of my bunks, and where the uprights are, might be different from the standard CP 23 setup, due to my having to put the uprights where the cross supports are.

Anyway, right now, my boat sits on the keelboard, and only the middle upright is touching the keel. The back is about 4" away, and the front is maybe a little less.

I can't just raise the uprights by hand, so I thought I would use a floor jack to press up and get the front to touch. The back ones are out of room to adjust, so I would have to bolt on an extension (which I already have done for the front.

Here's my plan:

1. get the bunk wet, to help it bend instead of crack.
2. jack up the front, see how it goes, stop partway, let the wood adjust.
3. hope for the best.

Here's what I would like to know from any of you who can do some measuring for me:

How long are the bunks you have, how are the uprights distributed (one on each end, middle one exactly in the middle?), and how much of the board touches the hull?

I have an extra set of uprights that I can put in, or I could, in fact, move the rear ones forward to another crossmember to better adjust and simulate the normal distribution, etc.

Also, I am at home now, being a worrywart over the plan, and when I go down to the boat to do all this, it might not be as complicated as I am making it, but I'd like to play this through mentally to see the best plan I can have, realizing I will have reality set in.

After all, Ike said something to the effect that planning is everything; the actual plan is nothing.

Thanks in advance for any input!

Bruce

[Shawn]

Bruce,

Can't give you any exact measurements as my 23 is long gone. I think they were just pressure treated 2x4s about 8' long.

I would suggest you don't worry about getting maximum contact from the bunk boards. I replaced my bunk boards on the trailer and when I then readjusted them with the new boards I made it so I had great contact all over. When it was time to launch it was *very* difficult getting the boat off the trailer. After I finally got it floating I adjusted the rear uprights to not curve up to meet the hull and instead kept them flat from the middle upright back. (Also made it so that the extension could extend even further on the trailer) The bunks are really just keeping the boat from falling over side to side, the majority of the weight is on the keel. The 2x4s are very easy to bend as needed by jacking on the uprights. After sitting in position for a season they tended to take a set and I dropped them each year to paint the bottom.

Hope this helps,

Shawn

[BruceW]

Thank you, Shawn,

Yes, that was a helpful comment. I particularly like the part about the back uprights. I do want the boat to slid off! Also, that would be better for me if I don't have to put in some extensions to those.

What I will do, is try to get the front to touch. I think jacking the front ones up will be worth the effort.

Something I didn't mention is that I might want to arrive at the boat when it is too dark to launch, sleep aboard, and feel good that my weight added to a quarterberth won't tilt the boat.

Regards,

Bruce

[brackish]

The bunks on a stock trailer are nine feet long, and are 2 x 6 treated.  The uprights are 44" center to center longitudinally.  They are curved to conform to the hull, so your idea of bending them is sound.  When my boat is on the trailer the last six or so inches of bunk fore and aft do not make contact with the hull, but the uprights fore and aft are still providing support.  I never tried to "bend" them up any more, particularly in the after area, because I thought it would make the boat harder to retrieve.  Pic shows the curve.  There is a post on this site that gives the dimension at each set of uprights so you can determine the relative difference, although the exact dimensions may not be the same for your trailer.  But the relative difference should be right.  The second pic shows the location of the uprights relative to the hull, so you can compare with your trailer.  Good luck, my boat isn't on the trailer now, but the trailer is in the back yard available to measure.

[BruceW]

Thanks, Brackish.

I will get down to my boat next weekend, and see what the relative lengths are from upright to upright, and see what I can make happen. I feel like I can lower the middle ones a tad, and jack up the front ones a tad, and then let the rear ones just be where they are, but will do some comparing when I get there.

[Blown Away]

http://cpyoa.geekworkshosting.com/forum/index.php?topic=4893.msg34303#msg34303

Bruce, I set up a new trailer a few months back and received this thread from one of our members that proved to be most helpful. I set the trailer up, drove out of state to pick up the boat and all measurements were within a 1/2 inch accuracy when the travel lift set the boat on the trailer. Good luck and hope this helps.

[BruceW]

Yes, I used that thread originally; now with my fixes, the issue seems to be the relative position of the uprights.

Still those measurements were very helpful.

Now on to more experimenting next weekend.

[BruceW]

Well, I made progress! upon launching the boat, I went back and looked at the bunks. Based on my previous calculations, I was going to raise the starboard bunk a bit. I decided to go up 2 inches. Went over to port side, and, Shazzam! It was already up that mount. Hmmm, I must have interrupted myself with original adjustments.

Anyway, I just left the port as it was, and when I retrieved, the boat was more stable. Two things: some barnacles had washed or scraped off, and the higher starboard bunk pushed the boat closer to port one also, and it seems nearly just right. Next time, I will raise them each a scoash more and measure them to get them even.