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Author Topic:   Trailers: Adjusting the keel rollers
kamie posted 05-24-2004 06:50 PM ET (US)   Profile for kamie   Send Email to kamie  
As I was putting the final touches on the trailer I was wondering. When you level the keel rollers do you:

a. Level the frame of the trailer and then level the rollers?


b. hook the trailer to the tow vehicle, park it on reasonably level ground and the level the rollers?

In the first case, the boat will probably not be level when towing where it will be in the second instance.

tuna1 posted 05-24-2004 08:17 PM ET (US)     Profile for tuna1  Send Email to tuna1     
I load boat on the trailer,then using a floor jack under the keel adjust each roller so it carries a equal load.The trailer will flex when the boat is on it,and the roller will not be loaded equally if the trailer is set up without the boat on it.In doing it my way one hand will lanuch a 25 footer or a 13 footer.
kamie posted 05-24-2004 10:10 PM ET (US)     Profile for kamie  Send Email to kamie     
This is probably the ideal way to do it, but I am not that lucky. I need to get the boat on the trailer and then drive her 25 miles home before I can make those type of adjustments. The most I think i'll be able to do in the marina parking lot is to snug up the new bunks against the hull and tighten.

jimh posted 05-24-2004 10:22 PM ET (US)     Profile for jimh  Send Email to jimh     
With the boat off the trailer, stretch a string from the most forward roller to the most sternward roller. All the intermediate rollers should just touch the string. The keel of a Boston Whaler is straight.
kamie posted 05-24-2004 11:46 PM ET (US)     Profile for kamie  Send Email to kamie     
Thanks Jim, I am going to guess that it doesn't matter if the trailer is level as long as the keel makes good contact with the rollers. I actually used a 2 X 4 to make sure that the rollers all touch and roll.
jimh posted 05-25-2004 07:49 PM ET (US)     Profile for jimh  Send Email to jimh     
The method suggested above (by "tuna1") using a jack to force the rollers upward is a technique that is interesting when trying to adjust the roller position while the boat is loaded on the trailer.

May I ask:

--how one measures the force under load when adjusting the rollers?

--how one knows that each subsequent adjustment has not affected the previously adjusted roller?

It would seem that as each roller were adjusted to bear a particular weight, this might affect the weight being born by adjacent rollers, and some of these might have already been adjusted to the particular weight.

In additional, the weight of the boat is not entirely uniform, so it would be difficult to say with certainty what the weight born by each roller ought to be. It would be reasonable to assume that the weight distribution on the rollers might be non-uniform because the weight distribution in the hull is non-uniform.

LHG posted 05-25-2004 08:50 PM ET (US)     Profile for LHG    
I set my rollers with the boat NOT on the trailer. Since the keel is perfectly straight, I stretch a string (tight) from the very back roller to the very front roller before the keel curves up into the bow. Then adjust all in-between rollers to the string. Any rollers forward of this point have to be set by trial and error by rolling the boat back and forth on the trailer until correct.

Then, winch the boat up on the trailer, with the bunks set so they DON'T touch the hull, letting it rock side to side a little. Then I set the bow stop and winch height, so that the end of the keel is only about 1" behind the last roller. The boat's bow eye should be snug up UNDER the 3" or 4" bow roller (much better than a "V" stop). This gives you panic stop protection.

Finally, the outside bunks are set last, with the boat ON the trailer. Set one side so that the boat is level. Then put a transom strap on it and crank it down tight on that bunk. Someone standing on that side of the boat also helps.
Then adjust the other side bunk up to the hull, tightening bolts for just enough resistance so that you can then use a hammer to force them up snug. Then tighten all the way and you are done! The boat will launch and retrieve extremely easy, with almost all weight on the keel rollers. Vertical guide ons, adjusted tight to the hull, are also recommended if your boat is longer than 18'

tuna1 posted 05-26-2004 12:52 AM ET (US)     Profile for tuna1  Send Email to tuna1     
I grew up in the days(1950-60's) of Wooden lapstrake boats and a knowledgeable boater would only own a "Holsclaw Bros." boat trailer.They were the best tilt trailers(no longer made,i still have 2-1 under a 1969 20' Bertram Moppie,the other under a 21'Boston Whaler Yankee Voyerger(a Ray Hunt design 24 degree Deep-V hull- HiLiner mold) with a OMC(Jacuzzi YJ pump) 290HP 350 Chevy Jet Drive,purchased as a unfinished blank when whaler move south from the Rockland plant) with more than a half dozen black rubber keel rollers with bunker rollers by the dozens and a hand winch.You did not dunk the trailer in the water,you might at times get the tire's sidewall wet but never the rim.You never used the motor to assist the boat on or off the trailer.You pushed it off and winched it on(25'boats on down).

If your keel rollers weren't adjusted properly they set a hook into the keel of the boat and the keel rollers were crushed with flat spots and you could not move the boat off the trailer. The keel rollers HAD to support the boats weight and they were only 5" in width-that's why there were so many rollers.

That's why/how i learned to set up a trailer - if you didn't have it setup right you could not move the boat off the trailer no matter how hard you tried.Many a person at the ramps would try backing up fast and putting on the brakes or would submerge the trailer and tow vehicle.But the equipment would not last long at that rate.

tuna1 posted 05-26-2004 01:19 AM ET (US)     Profile for tuna1  Send Email to tuna1     
JIMH - you use a wooden block on the jack's top which is under the keel ajacent to the keel roller you are adjusting either up or down by comparing the impresssion left in the roller as to the ones on either side.Then as a final test you check how it rolls off at launch and compare the impressions left in the rollers as to how well you did the adjusting.You may have to do some little corrections before reload the trailer.

Yes it takes a while to do- but every boat trailer i have ever done can be lanuched and reloaded single handed and that is my "Reward"-not looking like the other 3/4 of crappy trailer setups out there.....

The best out there now is a properly done "Float-On" type trailer IMHO.

linust posted 05-26-2004 03:37 AM ET (US)     Profile for linust  Send Email to linust     
I have to question the string method mentioned by jimh and lhg. Disclaimer: I don't have keel rollers, in fact (as some of you know) have a galvanized EZ-loader roller trailer (32 rollers, 16 half of which are within 6" of the keel.

I just finished replacing the hardware package (U-bolts, rollers, bolts, etc) on my trailer. As I didn't have anywhere to easily moor my Revenge for the few days effort it took (spread out over a couple weeks) I took to doing the work with the boat on the trailer. In order to unbolt/remove the roller carriers (4 of them, each holding 8 rollers) I put a 4' long 4x4 with a groove cut in it under the keel to jack up either the front half or stern of the boat (while the other end was firmly resting on the trailer. When raising the front of the boat off the trailer, there is quite a bit of flex in the frame rails of the trailer--you could easily move the trailer coupler 6-9" up & down without noticable motion in the frame from the axles back. Granted, this is not a normal mode of operation for the trailer, but it does leave one wondering.

tuna1 posted 05-26-2004 11:19 AM ET (US)     Profile for tuna1  Send Email to tuna1     
Had a 23'Uniflite Salty Pup that came on a EZ Loader with no keel rollers.I did not like the trailer at all.When loading the bow i found it poped off 2 internal braces Uniflite had glassed into the bow area for added support because the rollers just so happen to load either side of those braces.

Uniflite at the time made all the US Navy Vietnam riverrine jet patrol boats used overthere in that war/fuc_up!(SORRY BUT THAT THE BEST ADJECTIVE I HAVE FOR THAT SCREWUP)

Those rollers don't have enough surface area to spreed the load over and can load a area with a very high load when being pull onto the trailer.Indeed there may be enough when all are touching when finally the boat is loaded,but in loading it a very poor design IMHO.Sold the setup because i hated the sounds the boat made when loaded on the trailer,but still loved that boat,wish i had foresight enough to have kept boat and found a "Float On" type trailer.

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