Heavy duty tilt trailer plans

[driveshaft22]

Hi, I thought id share my plans for the new boat trailer I have designed and will be building in the next few weeks. Im a big fan of SketchUp 8 for making 3d Plans, so if anyone wants a sketchup file of this drawing please let me know and that way you can rotate and zoom to see all the details and modify it any way you like.

Here is a screen shot of the plans. All the materials including rollers and axle kit so far have cost me about $800AUD.

Any feedback is welcome, at this stage Im not quote sure of the axle distance for the hitch but Ill have a better idea once the frame is together.
Thanks

 

[Ranchero50]

Be sure to make your winch post movable. I'd also suggest figuring out how low you can get the hull to the ground as it makes it much easier to splash in shallow water or beach areas. I chose to widen my axle so the hull could hunker down closer to the trailer frame without hitting on the tires.

 

[driveshaft22]

Hi, thanks for the reply.

I had the same idea, keep the boat as low as possible, but not for launching as it is a tilt trailer, but the wind resistance while towing is a factor.

The height it sits now is as low as I can go, as long as I get the rollers positioned in the right place it will be fine. The reason being that it is set up with 31" Landcruiser wheels and the wheel track width has to match the tow vehicle because it will be used offroad as well as normal conditions. For example when driving in sand if the trailer wheels don't follow the vehicles wheel tracks it can be like towing double the weight.

The springs are eye to eye with greasable shackles and it will have shock absorbers as well. This trailer needs to be able to handle rough roads for long periods. Some roads out here in the outback are 1000 kilometres of corrugated dirt, the poor boat will take more of a beating on the trailer than in the water.

Yes the winch post is movable.

 

[Ranchero50]

If that's the case I would not use rollers. I would go with 4 wooden bunks with UHMWPE pads. I think the roller setup will just pound divets into the bottom of the boat where the rollers sit over time. Make sure you are supporting the transom as well. If not the floor will buckle causing a hook which will keep the hull form planing out as easily as it should. The UHMWPE will allow the hull to slide off very easily.

UHMWPE = Ultra High Molecular Weight Poly-Ethylene.

 

[RiverBottomOutdoors]

I have no experience with tilt trailers. I don't understand the benefit of them. Educate me...

 

[Ranchero50]

Non tilt trailers require the bow to ride over a keel roller on the rear frame cross member putting all the load on that cross member. A tilt deck will rotate as needed to balance out the load as it goes on and off of the trailer. It'll also kinda let you load a boat that's barely floating easier than having to lift the front all the way up to the last cross member.

To me it's just another area on the trailer that is weaker than it needs to be. If the OP is going to be running off road with it, I expect the pivot and latch to wear pretty fast.

 

[driveshaft22]

I thought the same as you that it would be weaker, but after using a couple and designing this new one, I am convinced that it will not be in any way weaker.

I should mention that I have been a Boilermaker for 10 years and my father was a builder and his father was a sheet metal worker. Add to that my middle name should be "overkill" and you end up with 1 very tough trailer.

Here is a pic of the tilt action, obviously it stays connected to the tow bar of the vehicle. As the weight moves backwards, the wheels will creep forward allowing the tilt.

 

[overboard]

To me it's just another area on the trailer that is weaker than it needs to be. If the OP is going to be running off road with it, I expect the pivot and latch to wear pretty fast.[/quote]

I would also think that to be the weak point. Don't know if it would help to sheath the tongue in an inverted square U, that's added between the pivot and the front of the trailer for added strength and less torque on side to side movement of the tongue.
My tilt has that on, as I think most do.

 

[riverbud55]

Looks good on paper,, just built a trailer for my jon https://www.tinboats.net/forum/viewtopic.php?f=49&t=32006,, Used a torsion axle from Northern tool https://www.northerntool.com/shop/too..._620183_620183 ,,, I'll never buy or build another trailer without them,, my trailer came out 14-1/2'' to the bottom of the frame with 175/80-13 tires that are 23'' high,, my axle is 10* could make it lower by using a 0*,,, torsion axle allows each tire to move independent of one another,, gives less un-sprung weight by not having a live axle taking away the spring bounce, much lighter, nothing to wear out unless the rubber give out on the inside and don't think that will happen in my life time

 

[driveshaft22]

Hi thanks for the replies.

I thought about the independent torsion axles but the axle kit came up cheap so I went that way.

Here is a close up of the A frame where it meets the draw bar. It doesn't have the lock pin drawn in but you can see where it goes.

As you can see it does have an inverted U which I can add a pin to go thru the draw bar as well. I can also use some neoprene or similar material to make sure there is no play in it.

 

[Ranchero50]

I wonder if it wouldn't be better to use a bolt running vertically to lock the tilt mechanism.

Or to use the plate setup in the drawing weld a bit of pipe onto each of the flat plates so that a bolt would fit through snug. My concern is with a simple drilled hole in a metal plate is that you are loading your pin in shear and all the vibration / load is going to be transferred through that small area. I expect it'll wallow out pretty quickly from vibration. The pieces of pipe would transfer the load through a longer area and wear much less.

 

[MikeA57]

A few years ago I rebuilt an old Holsclaw tilt trailer from 1956. Had it powder coated back to original colors (or as close as I could get), and posted it here. A link to it is in my signature. Some of the pictures didn't make that post though, but they are applicable to this conversation. Here's some detailed shots of the tilt mechanism. Some say that the tilt area would be the weakest point and I can understand that but the hinge pin on this is a 1/2" piece of allthread that was replaced when I rebuilt it. There was nothing wrong with the original hinge pin, I just decided that it was over 50 years old at that point so I may as well replace it.

You will notice a weld in the area where the main tube meets the split. That was done at some point in the mid-late 70s when my Uncle Charlie backed the boat into a tree. It didn't hurt the boat, but the main tube was a little bent. They cut out the kink and re-welded then put the additional plating around it to restrengthen that section.

I too, would suggest making the crankstand moveable. I've included a picture of mine showing how it is set up as well.

I hope this helps with your design. I can attest that this is one heavy duty trailer that, like I said was 50+ years old when I finally got around to finishing the job I had started several years before and I feel very confident that this trailer could last another 50 years.


Mike

 

[MikeA57]

Oh yeah, and one of the things that I have not gotten around to trying is putting a heavy spring on the hinge pin itself so that it would automatically spring back to the closed position but I'm not sure that it would work when the tilt was coming back down with the load on it. The cotter pin drilled through the pin keeps it from coming all the way out when you unlock the tilt and I would have put a washer against that, then the spring in front of that (towards the front of the trailer) and it would tension against the inner block as you pulled the pin. Hope I didn't over-explain it and confuse the issue...

Maybe a picture will help.

It would help if you "accidently forgot" to lock the pin. (Don't ask how I know this... :roll

Mike

 

[driveshaft22]

Hi, thanks for the reply.

Your idea is similar to the original trailer this boat came off, which does have a spring loaded latch and where I got the idea from.
I didn't reinvent the wheel so to speak.
Here are the pics.