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Pete McCrary

Trailer without rollers . .

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The original trailer for Chessie (a Core Sound 20 Mk 3) carried her (1" yellow pine keel w/SS half-oval) on three hard-rubber rollers.  The side bunks were adjusted to carry loads just enough to keep her balanced at the verticle.  That arrangement concentrated her load on just three places and, over many miles at highway speeds, the stresses caused by potholes, RR Xings, unseen speed "humps," etc., -- caused the rollers to be severely damaged at their centers (the only load-bearing part).  Note that there has been no noticeable damage to the keel.  The chipped-away rubber pieces made the roller no longer cylindrical to the point that they often didn't "roll" at all -- causing launching and retrieval problems.

 

I learned that Graham had similar problems and was considering a trough with many rollers.  That reminded me that I had used flat platforms to carry my CLC PocketShip and a Com-Pac Eclipse (both had, respectively, wide ~2" & ~4" flat keels).  So, maybe the concept would work for a CS20.3 and other boats without flat keels.  So, here's what I came up with.

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This shows the rip-cuts made on a 16' X 2 X 8 straight piece from Home Depot.  The bottom of the board was covered with two epoxy saturated and overlapping (only by an inch at the center) 4 inch X 10 ounce FG tapes over the entire length.  The top and sides were covered with three coats of neat epoxy -- and the top with a final coat of neat epoxy mixed with powered graphite.  For Chessie's trailer I trimmed the 16' trough down to just 14 feet.


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The "rough cut" cross section.  The sharp edge of the half-round centerline trough was rounded over with a smooth plane.  The 4 coats of neat epoxy tended to collect (at bit) at the bottom of the half round -- which was desired, as it would carry the concentration of stress and sliding fiction.  BTW, the half round SS screws (thru the keel's SS half oval) were "smoothed" over.

 

I measured the height of each roller (above) their wooden mounts and planned to mount the trough such that it's bottom would duplicate the position of the [three] rollers being replaced.  Alan provided me with offsets (from the waterline) of the keel at the three points where the rollers were mounted on the trailer.  From this I determined that the mid support (under the trough) should be ~ 1 and 15/32" lower than a straight line from the forward mount to the aft mount.

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Trough lined up on the trailer centerline.

 

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Forward support with spacers.  Notice X-beam doubler (new wood) under.  View from port side slightly aft.

 

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Middle support.  Trough is not loaded.

 

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Now the trough is artificially loaded with clamps.  When the boat was lowered onto the trough, there was ~1/2" space -- into which was placed a spacer.

 

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Aft support.

 

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Shallow-V guides to help guide the keel into the trough.  Note that the CB catcher is raised so that the CB won't hang up on the X-beam.

The centerline of the trough was further lubricated with paste floor wax.

 

Next I'll report the proof-of-concept trial launch and recovery.

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Yesterday, April 1, was the launch test -- abbreviated.

The trough worked just fine for launch and recovery.  Much better than the three rollers that I was using.  Here's how it went.

Hampered by a very low tide and shallow ramp caused by three days of strong winds pushing water out the Potomac.  I wanted to be into the water as little as possible -- but I was worried that the sliding boat might "plow" into the concrete ramp (just about 15" where the boat would plunge into the water off of the trough).

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The above photos show where I wanted (but didn't) launch.  The tires were in the water, but the wheel hubs just above.  So, I backed down a little deeper.  Later in the season, I'll try a shallower launch.


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Wheels under, but not the fenders.  Boat not yet floating. 

 

Next I unhooked the safety chain and the bow eye, drifted back a few inches and "tapped" the brakes.  Chessie just smoothly slid into the water -- pretty-as-you-please.

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Shown above she floating but secured by her bow eye ready for recovery.  Notice the yellow stripe on the dock -- that marks the end of the concrete ramp.  You can see that the trailer wheels are not far from it.

 

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Recovery was easy, single-handed.  Nudging boat's keel onto the trough (above photo) -- I took the winch cable and hook onto the walking-boards and secured it to the bow eye -- then (using the "high-gear" on the two-speed winch crank) she was easily pulled full-up onto the trailer.  The effort was much easier than that required to recover over the rollers, where near the end I'd have to switch to the low gear.  I think the damaged rollers weren't "rolling."

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She's part-way up.

 

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I think this is the full-up position at recovery.  At launch the mooring lines would have been cleated to the dock.

 

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She's full-up and secure.

 

Next time I'll try launching (and maybe recovery) with the trailer backed down the ramp just so the wheel hubs are dry.

 

So far I feel pretty sure the wooden trough approach is much superior than the rollers.  And simpler!  KISS.

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Very nice Pete, gives the keel great support full length.  I have had good luck with boat trailer carpet.  When wet it’s slick and seems to provide good protection against chafe.  In fact I have it on my sprits and after 4 years no damage to mast or sprits. 

 

We installed the planks  along side of the trailer frame,  makes a big difference in ease of recovery.  

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When I wrote a reply to your thread right above the box where I typed my response there are several editing buttons. One of them controls strike-through. Simply select the text that you inadvertently enabled strike-through and then click the strike-through button.

 

Edited: I tried to go back and edit my post and I notice that the strike-through button is not available when editing an exisiting post.

Edited by Mike Vacanti

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Thanks for the suggestion Mike -- but I couldn't make it work.  However Frank Hagan got into the "codes" and all is well.

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Nice solution Pete; thanks for the pictures. 

 

My boat still rolls off it's five rollers (I haven't had to put the trailer lights in the water yet), but it isn't rolling as well as it did at first.  The Stoltz rollers are holding up well though; there are no flat spots and they still roll.  I think the cause is that the board supporting one of the rollers has sagged.  I'm thinking of adding another trailer cross member and roller.

 

If people are going to go the roller route, I do think it is worth spending the additional money for Stoltz rollers. 

 

I do think your solution is best in the long run Pete. It was a lot of work to get the rollers to work right as roller brackets have such a limited range of adjustment I had to modify them to get the rollers high enough to support the boat weight.  Stock trailer cross members aren't always in the best spot and there aren't enough of them.

 

Nice work Pete, as usual I'm jealous of your drawing ability.  That is a skill that many of us that grew up in the computer age lack.

 

 

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A few days ago I was able to recruit an onlooker at the ramp to take a video of Chessie's launch.  This time I backed the trailer into the river with the water just about an inch below the the WL boot.  That put the wheel bearings just under water.  Here's what it looks like:

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This shows position of the rig just prior to the launch video.

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Next is the video of the actual launch.  I just let the pickup and trailer coast backward about a foot, then hit the brakes!  That overcame the "slip/stick" effect -- and she slipped smoothly into the river.

 

In the pickup I carry a can of Johnson's  paste floor wax -- and before recovery give the trough a good swipe.  This time the trailer wasn't so deep into the river [than the first time] which caused a little harder cranking on the winch.  The last foot or so I shifted to the low gear.  The winch hook was attached from the dock and the boat nudged onto the end of the trough.  Once in the right place the tug of the winch cable kept her "lined-up."

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Shown here after recovery.

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I consider the modification a significant improvement for both launch and recovery -- AND a much gentler highway ride for the boat.  Probably less trailer maintenance as well.

 

Next time I'll see how it worke if I back only so far as to keep the wheel bearing dry.

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Your design engineering and math knowledge are wicked smooth, I wish I paid better attention in Physics! 

I’m very impressed and hope to incorporate your design whenever I get a trailer. The incorporated graphite is a super idea and got me thinking of a plastic like Delrin or even Teflon which have similar coefficient of drag that might work. Just the same, I think your ideas’ are pretty rock solid, especially like the old school Johnson paste wax idea!

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Chessie has been launched again -- and this time the trailer was backed less deep down the ramp.  The photo below shows that the keel at the transom was just into the water rather than up to the bottom of the boot.

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The water level was still just above the wheel bearings.  I did the same launch maneuver (drift back a little, then hit the brakes) -- and the boat slid off, but not all the way.  To get her all the way off I had to pull quite hard on the mooring lines.  But she did slide off.  Apparently the stern needs to have a floating component to assist in the launch.  Next time I'll back down the ramp so that the water comes up to the bottom of the boot.

 

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Ready for the launch maneuver.

 

Cranking her up on recovery was also a bit harder.  But the trough keeps her lined up nicely -- making solo recovery much easier than the roller setup.

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Dave, a roller wouldn't help.  I used to think so and installed one [at the trough end] for my CLC PocketShip.  But when I sketched the ramp-trailer-boat geometry I could see that the roller didn't touch the boat's keel until it was almost fully on the trailer.  Here's a side-view sketch of my CS20.3 approaching the trailer on a typical ramp.

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River water surface shown by the blue "wavey" line.

 

The crank effort is not any greater than when I had three rollers.  But I suspect that one or more rollers were not "rolling" because of damage.  So I was probably just sliding the keel over a roller or two.  Towards the end (of the recovery) the crank effort naturally increases more because the radius of the cable shaft [probably] doubles, which would reduce the winch's mechanical advantage by half.  But the lower gear can offset that.  And, of course, the boat displaces less water as it moves up the trough.

 

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The reason I suggested it was because it seems you want to keep your bearings dry.  Your boat wouldn't achieve the position in your sketch  during a shallow launch or haul.

 

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Yes, I had hoped that with the trough setup I'd be able to launch and recover while keeping wheel bearings just above the water.  After two launch/recover sessions, I don't think that will be achieved.  However, launching and recovering [solo] is definitely easier AND a softer highway ride for the boat and no more damage to rollers.

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8 years of managing a small boat marina and the only really successful dry launches and hauls I have seen require many rollers (hull and keel) and a power winch.  Your trough and a deep set may just be the best way to solo.

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I think you're right.  At this early stage my only concern is how well the wood trough holds up to the wear and tear of launch and recoverys.  I tried to smooth over the oval-head screws (holding fast the 3/4" half-oval) -- but the job isn't perfect.  If need be, I could cover the sliding surface with something like vinal siding -- carbon fiber?  Only time will tell.  Maybe what I have will do ok.  We'll see.

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Hi Pete, our local boat trailer supplier has a spray that lubricants the carpet on our trailer.  A quick spritz of this stuff and our boat glides on and off the trailer.  We do have the carpeted bunks, but if friction is a problem possibly consider carpet and this lube on the carpet.  Doesn’t make a mess on the boat either 

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7 hours ago, Hirilonde said:

8 years of managing a small boat marina and the only really successful dry launches and hauls I have seen require many rollers (hull and keel) and a power winch.

   I used to dry launch Southbound with only three or four rollers, carpeted bunks under the hull and a manual winch - It worked quite well for me.  I parked the trailer shallow enough to keep the rims dry.

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I remember having a hard time getting Carlita off the trailer while I was at Port Townsend. I have worked on my rollers since and they all turn smoothly. The forward roller is grey but it is not in contact when the boat is being pushed due to trailer flex. The next two are yellow and the aft one is one that I made out of uhmw plastic and it rolls very well. 

 

I usually launch Carlita at the shop and use the tractor where I can keep tilting the trailer until the boat has no choice but to roll off. I had a really difficult time launching Carlita at the ramp in South Carolina. I started with the wheel bearings clear of the water. It became very clear that there was no way that I could get it off without going deeper. I cannot remember how many iterations I went through including climbing on the boat twice to make sure that it was not he centerboard causing the problem. The exhaust was almost in the water by the time I floated the boat off. I had spent a good deal of the previous day on the trailer lights and hated to have to submerge the trailer.

 

I want the boat to roll off easier than Petes trough as I am still not keen on submerging the wheel bearings.

 

On Friday evening I refined my version of Pete's trough but with 10 home made PVC rollers.

 

Wish me luck. I will let you know how well or bad it works.

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IMHO, the secret is ramp angle, as in Graham raising the tongue with the tractor. I remember an add from the 50's for a trailer with the tongue pinned under the trailer frame back in front of the axle. The frame locked onto the tongue for travel and unlocked at the ramp letting the frame rotate to an angle to let the boat slide off. There was a photo of launching a skiff with the rear wheels on a 3' high culvert!

If the trailer is too flat with just the rims in the water at a given ramp, changing supports (trough, roller trough or whatever) won't allow a launch. Two options to consider would be a snatch block under the boat for the winch wire to pull the boat off, or a 'brake tongue' to increase the angle.

 

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