What is a tall hitch height for a bumper pull trailer?
 

I am making a trailer dolly - basically a second trailer that sits between the truck hitch and a boat trailer for shallow water launches - and am making both ends height adjustable.

My ball is set to 20-3/4" on the truck so that is the number I am working around for now. Adjustment increments are 1-1/4".

Based on the hitch height question - what I am getting after is how high I should make the top end of adjustment. Another 2"? Another 6"?

I suppose the height isn't "critical" - I just like things to pull level so not knowing everything the dolly would be used for in the future I am trying to plan in for some more flexibility now in adjustments.

Sorry, I have no input on the hitch height question, but I have a question of my own about the dolly.
Is the dolly going to be articulated at the truck and boat trailer ends? Or fixed at one end or the other? This dolly will have it's own axle, correct? With it able to swing at either end I would think reversing with any kind of control would require lots of practice and patience.

Tom - the dolly is articulating on both ends with its own axle.

I thought about a rigid extension but there are a few problems with that theory.

With the boats I am working with right now (both open camp/utility style boats with bench seats - a 16' and and 18') the tongue weight isn't too much, but I want to build one of these once and have all my future bases covered and tongue weight becomes a bigger problem the heavier it is. Cantalevering that weight off a 20ft extension hitch would be a nightmare I would imagine.

The other problem is launching boats where there is no launch ramp - isolated lakes in the middle of no where. We have dropped the trailer off an embankment by a bridge to drop the boat in a stream going out to one of the lakes before. In such a launch a rigid connection would prevent the dolly from articulating over the edge of the embankment, instead riding on the extension frame and folding it in 2.

On a normal launch where we're just dealing with shallow water on a regular launch ramp the backing up part won't be hard. If we're lined up straight anyway there isn't much moving around other than rolling backwards.

The dolly will extend to about 20 feet or so - that is longer than axle distance from the hitch to the axle on the boat trailer itself. So from a maneuverability perspective, the dolly will react slower to turning than the boat trailer does to begin with since it is longer.

I’d use tubing to lengthen or shorten the tongue as needed. Like pup trailers loggers and dump trucks have. I’d also have a winch set up to retrieve or launch the boat while keeping the pickup on solid ground.

Ryan - thanks for the note.

I have the winch covered. I use a Superwinch Terra 45SR for my utility purposes. I have a jumper cable I cut one end off of and put a big 150A powerpole connector on, same for the winch and some other things. It works wonders on moving all kinds of things. I just used it in the past couple weeks to replace the steering gear box in my truck. I hung a block off a couple ladders and hooked the winch to the bottom, dropped the line through the engine compartment, and looped the line around the gear boxes. I also pulled the track bar and mounting bracket back up in to place. Good stuff. There is plenty of power in that little winch for the boats. In fact, if I block the line a few times (I have 3 or 4 of the 9k Superwinch snatch blocks) I can pull the truck too.

I'd just rather make things easy and float the boats on and off instead of winching. Though, I will have the option of both.

I will post up when I am done with the dolly. I would say I am about 2/3 of the way there. It may be through the weekend to get the rest of the fabrication done. It is coming along, though.

Hey Steve, as Tom mentioned above, backing that rig will be a nightmare. You will need to be able to see the wheels at all times to be able to make corrections, which will be many. I've hooked thousands of sets of doubles when I was driving trucks and even backing them short distances was a challenge. Also, how are you going to transport the dolly you are talking about to your launch location? Are you going down the highway with it already attached?

Hold your questions until you see it. I'm sure that will answer most of them.

I'm a few days out of having a "rolling chassis", but things are coming along. Today's task is to try to iron out my welder. I swapped wire on it and the welds are terrible. It may be a voltage issue. If not, I'll try to find some different wire. I went through 2 new spools, both different brands, and they both won't hold an arc like what I ran out of. Between some welding, making holes, and cutting some more parts from stock I have quite a bit more work to do.

I got the welder situated and ended up needing a new mask/helmet. The one I got had a battery in it that was negative voltage... So needless to say it wasn't working right. I took it back today and we got the batteries ironed out - works now. I'm hoping to make some more headway today. I don't think I will get to a rolling chassis tonight, but if things go well it is a possibility. I am done re-working parts (with the voltage issue on the welder I cut out all the welds I did before and re-welded them - lotsa work). The new mask/helmet is a Miller Digital Performance. I can see my welds a million times better with it so that should improve my weld quality tremendously.

With any luck I will have things rolling today. I got slowed down on the axle assembly yesterday. I am making struts to stabilize the axle tube fore/aft as well as from rotating about the main frame. They are 2"x1/4" angle iron and I was having trouble getting the geometry to mesh right. I still can't get them perfect, but I can press the angle I need on one side in my hydraulic press that will "work", not pretty, but it will "work". Once I get that out of the way I will tackle the front frame section. I have the coupler and adjusting sleeve already fabricated ready to throw on - I just need the frame to line it up with and start making my holes. Both the coupler and ball ends of the dolly are height adjustable in 1-1/4" increments.

Not rolling just yet... but close. I have 2 more brackets to weld and about 16 holes to make.

I ended up spending more time on the struts than I anticipated. The bending I was trying to accomplish with the press ended up not working. The parts just weren't fitting right and I wasn't happy with it so I spent the time to straighten the bend and ended up making another cut then bending and filling the crack with weld. I didn't do anything with the second strut other than my initial cuts, no bends, until I had the first one right. Once I got the first one reworked and welded up I modeled the second one after it - mirror image. The problem I ran in to is the first one was slightly "off" and the problem was magnified in the second one. So I had to make another cut, bend, and then re-weld to fix.

The joys of custom fabrication...

The rear frame/axle/hitch assembly is basically done, the last bit of work is on the tongue and a couple of the main frame segments.