More Trailer Work

[Kern O]

It seems like I'm spending more time on the trailer than I am the boat, but since every time I use the boat it has to come off and on the trailer, the trailer needs to work. I want it to be setup so I can load and unload by myself, no matter if it is at night or windy. That gets more difficult as the boat gets bigger. I'm still questioning my sanity for buying a 34, but I did, so I have to make the trailer help out.

Getting the boat off the trailer is easy. Once the trailer is deep enough, it will float right off. But putting it back on with a cross wind or current can be a fight. I've found that the toughest part is getting the bow centered to the bow stop. It seems like even if you think the boat is in line with the trailer, you can be off center and take a chance on running the bow into the trailer or the bow stop. If you can keep the bow centered long enough to get the winch strap on and pull the bow up to the stop, all is well. But it seems like every time I go from the dock to the winch, the bow has moved off center and is sitting across a bunk, which means a tug of war to get it back into the middle.

I fought that fight on the my Stamas until I put an aluminum V across the trailer and covered it with starboard. That improved things a whole bunch, but the bow was sharp enough that it tried to dig into the starboard. I thought about carpet, but figured it would cut too easily when the bow hit it.

The ramp I deal with is generally shallow, so I usually have to use the winch to get the boat forward on the trailer. I've found that it really helps to have rollers on the front of the trailer so you're not dragging the boat up carpet. When the trailer is in the water, it is sitting at a pretty good angle to the boat. The only part of the trailer that the boat even touches is forward of the trailer axles. So, I figured I needed t come up with something a little better than the aluminum and starboard routine. Here's what I did on the Jupiter:



The keel rollers let me pull it forward easily and the side rollers did a good job of centering it. Except, it was possible for the bow to go between the rollers and hit the aluminum arms, which is not good. I needed to come up with something that no matter where the bow hit it, it would both roll and slide to center. And once it was centered, it needs to stay there.

So, here's what I did today. First, I made a pivoting, three roller setup to support the bow and let me winch it forward easily. It is U-bolted to the cross member. None of the brackets are finished, they all still have square corners and will be cut down quite a bit. Once I got the three rollers in place, I sat there and stared at it to figure out how I could make the bow always go to center. I took a block of wood and drilled a couple holes in it at 35 degrees and stuck it under the rear pair of rollers. I put a 5/8 rod in the hole in the block to support some keel rollers in a V. I stacked three rollers on each side and it looked too long. But 2 1/2 rollers looked pretty good. So, then I made a support for the ends of the rods and mocked everything up. I'm not completely sold on it, but it looks like it ought to work. Here's what it looked like when I quit today.

[localangler]

WOW!!! you truely do some nice work. We need to mount a webcam on your hat so we do not miss a step of any of your boat projects.

[jenkinsph]

Looks good Kerno, can you add more support between the rollers segments to prevent bending the 5/8 shaft pins? Also would self centering rollers help at this point to correct the last foot of travel?


Steve

[Daddy'O]

Kern O,

What type of material are the rollers made of? Are you fabricating them also?

Wayne

[Kern O]

To answer both questions:

Daddy O: The rollers are standard off the shelf Stoltz keel rollers. They are about $ 20.00 at most marine stores.

Steve: You read my mind on that one. I looked at that for a long time yesterday and the problem is that every place I put a support bracket, it makes a gap that the bow can go into and chew up the gel coat. The 5/8 rod is 316 stainless, so it is pretty tough. I know it won't be able to withstand the force of the boat under power, but it only needs to exert about the same amount of force that I can with a rope. I know that's the theory, but reality is that that it is going to hit hard enough to bend the rod at some point. So, I made them easy to replace and set 'em up so they are just a simple section of rod with a bolt holding them in place. The alternative would be to use wobble rollers since they have a 1 inch I.D. The 1 inch shaft would be a lot stiffer. I suppose I can drill the rollers out, but drilling that deep in urethane can be a fight.

I'll post shots of the lash up later on.

[jenkinsph]

If you can have a wide v shaped guide that is raised and supported by a flexible mount that will capture the hull and guide to center while still floating the hull that may help alot. An arm mounted perpendicular to the lower face of the V could be mounted with a flexible torsion mount allowing the hull to ride over it and push it down. This way the V rollers would be in constant contact centering the hull, while having enough deflection to allow the hull to settle on the trailer keel rollers. With a trailer like yours maybe a vertical travel of 6 to 12 inches and 100 to 200 lbs deflection pressure for the V to be
pushed down? You may be able to use a simple torsion axle end mounted along a cross member on the trailer frame to accomplish this with the lower pivot point mounted towards the rear of the trailer and the extended arm to the V directed towards the tongue. Also needs to be ridgid enough to prevent any lateral movement across the trailer.


Steve

[Kern O]

Great idea, Steve. I like it and may well attempt to incorporate it down the line. I got so wrapped up in the present system that I killed a day and a half on it and have to move the project along. I milled a couple angled holes in a piece of stainless for the center support. It is held on with a U-bolt, which is the only simple thing I did. I The rods are held into the block with pair of 1/4-20 screws so they can be removed and replaced easily. I also drilled and tapped the end of the rods to hold the rollers on. It sure doesn't look like it should have eaten the time it did.

Here's the support block:



And here's the whole thing together and ready for weld and anodize:

[jenkinsph]

KernO nice machine work, hard to tell from the pictures but I assume the shafts are being pushed towards the block when loading. Any reason you did not drill sockets for the shafts to ride in? Seems like that would have reduced the screws to just being keepers for the shafts with all loading going to the sockets.

BTW, the V notch mentioned above could be lined with UHMW since the pressure against it is limited by the suspension, thereby giving you a smooth surface continuous from side to side with no places to snag.



Steve

[Kern O]

The picture of the block was taken looking forward. The block has 5/8 diameter "half bores" in it, so all the screws really do is to keep the shafts from falling out. I did not want to take the time to bore the holes, so I used a endmill to make them. You can usually count on an endmill to cut oversize, but not today. The shafts were a press fit in the bores. So, if you look carefully, you can see that the ends of the shafts were turned down a bit so they did not have to be driven into place. All of the loading is against the shaft seats and the outboard support. The block is a piece of 1.25 x 2.5 304 stainless, so it will be the last to fail. As I said, the only rational thing I did today was to hold it on with a U-bolt. I actually considered making the shafts out of 17-4 and heat treating them.

The torsion bar arrangement is an extrapolation of what they do with ski boats. Many of them a pivoting "bow bar" on the trailer that let the boat float above the trailer, but kept it centered once you managed to put the pin through the bow eye. I have a Carrera 20 ski boat with exactly that system on it.

[Southshore Marine Service]

That is some incredible work! Keep it up!