Thread: Trailer build II... the long haul.

Hi again, found this US site, for boat trailer builds, specs etc, thought it may help someone wanting to build a boat trailer or adapt the drawings and build a box.
http://www.fishyfish.com/trailer.pdf
Know this is Yonees post, but like a few ppl like me, needing help, until they put a trailer section here, had to post in here, sorry Yonee. Couldn't see any copyright protection anywhere

Yonnee

Im about to build a boat trailer for my 7.3 meter center console alloy boat. I have built the boat, well almost anyway. I have all the steel ready to get going, I was wondering if you would be kind enough to offer advice as I go. I can post pics for your to scrutinize if you like. I will start another post so I dont hijack yours. I will be ready in the next day or two.

Stu
Sunshine Coast QLD

I hope this gets through this is the third time I have tried to post and for some reason I keep getting a microsoft message and the damn thing disappears.

Here we go. Lucky you guys asked for the photo's I need to get to and do a bit of maintainance, there is a few rusty bits that need attention.

First this trailer was made about 27 years ago.I used the measurements off a friends trailer who had it professionally made. It was so great to tow that I copied the measurements but made a few changes ( You can easily tow at 100Kmh with it behind a Falcon and it just sits there. )

There were a few things that I didn't like about his. One was the ramps he had were big heavy ones which bolted onto the draw bar. I made slides and the timber ones I use go up under the floor at the back. I made the tailgate drop below them so you can then pull them out and hook them onto the back floor. The tailgate also comes off by just lifting it off the hinges and sliding back the side straps. (Pic 3)

It is just a big box trailer 12ft long 6 ft wide 1ft sides in 18 gauge steel. The suspension is rubber torque, The floor is tallowwood floor boards. It is great for small cars and fantastic for anything else. The local garden centre once advertised you could have a box trailer full of mulch for $20 should have seen his face when I rolled up , It holds about 4 times as much as a normal box trailer. Great for moving big stuff.

You should be able to see how the draw bar works, two 1/2inch bolts fix it at the front of the chassis (pic 5)

the back bolts are 3/4" by 4" high tensile if you undo the front ones it pivots on the back. Take them out unplug the wiring unhook the handbrake cable and the draw bar is can be taken away. It only takes afew minutes.(Pic1)

I normally don't have the high tarp on but I have been using it to store junk while I organise the shed. The frame for it is 1" tube which has sockets to put it together (the ends are shrunk down to fit inside the the expanded other ends)

I have always had one rule I don't lend it for anyone to put a car on. The car I tow doesn't have doors so I can get out of it easily when its driven onto the trailer but modern ones you would have to climb out of the window. Its not built heavy enough for most cars anyway but having seen what people do to borrowed trailers I suggest you keep an eye on who you lend yours to,if you do.

Thanks durwood , looks and sounds like a good set up.

That's Ok I don't really mind.

Durwood,

Niiiiice. Looks like an AL-KO axle set.

For those that don't know, as well as standard trailer axles, AL-KO make an Independent Rubber Suspension that works on a twisting action of a clover leaf shaped inner tube, compressing three solid rubber rods against a hexagonal (more like a triangle with its sides bowed out) shaped outer tube. Welded to the inner tube is a trailing arm with stub axle. They're great for boat trailers as you can option the outer tube to be galvanized and the mounting brackets doubled to allow you to 'U'bolt the axle/s to the trailer rather than welding or drilling through the chassis.
Their big drawback is overloading and subsequent failure. If you break it (usually you'll tear the trailing arm off the inner tube), you have to remove the whole axle and send it back to AL-KO to pull apart, re-make and replace a new arm assembly, and send it back to you.


Waz,

Be careful of using American based websites for trailer information. Our regulations may differ from those in the States and you could end up with advice that's not applicable or legal here.
Try this one. This is my trailer "Bible". It's the Australian Fedral Reg's and will give you all the technical information as to lights, reflectors, mudguard requirements, etc.



Stufart,

Firstly, Welcome aboard.

I'd be happy to help in any way. The biggest trick with boat trailers is axle placement. You don't follow the standard rule for a box trailer, and even two trailers with the same boat but different size motors will have different axle placement.

Is this a salt or fresh water boat? And if it's salt, are you planning to Gal dip the trailer? If not, we'll be doing this all over again in 5-10 years.


I'll be ready when you are.


Cheers,

Yonnee.

Hi Yonnee,
You are right they are AL-KO axles. One of the reasons I don't lend it as you explained overload them and they fail I made sure the ones I used were way higher rated than I really needed.

One thing that really got to me when I built my trailer was the poor quality of most of the hardware for them. Especially the ball couplings, the castings are so rough with saw tooth notches for the parking brake lever that were not deep enough for a lever to lock into and ball sockets which were way loose. Even the safety catch notch stopping the lock under the ball didn't work as they didn't have the casting finished well enough for the spring loaded catch to actually hook into the notch. I havn't needed to buy any parts for years but they still look to me to be lousy. I noticed the ones available overseas are of much better quality, especially the ones in the USA. They are made like a piece of high tech equipment not like a bit of back street casting. When I'm in the States later on this year I intend buying one to replace my ball coupling.

Originally Posted by durwood

Hi Yonnee,
You are right they are AL-KO axles. One of the reasons I don't lend it as you explained overload them and they fail I made sure the ones I used were way higher rated than I really needed.

One thing that really got to me when I built my trailer was the poor quality of most of the hardware for them. Especially the ball couplings, the castings are so rough with saw tooth notches for the parking brake lever that were not deep enough for a lever to lock into and ball sockets which were way loose. Even the safety catch notch stopping the lock under the ball didn't work as they didn't have the casting finished well enough for the spring loaded catch to actually hook into the notch. I havn't needed to buy any parts for years but they still look to me to be lousy. I noticed the ones available overseas are of much better quality, especially the ones in the USA. They are made like a piece of high tech equipment not like a bit of back street casting. When I'm in the States later on this year I intend buying one to replace my ball coupling.

Back then, you did say it was 27 years old, you wouldn't have had much choice over Carter Wesco. Now AL-KO have their own range of couplings, and Melbourne Trailer & Caravan Supplies use Trigg Brothers' couplings. Neither of these I've had a major quality issue with. As for the separate hand brake lever, the cast ones are rubbish. There are some fabricated steel one that are much nicer and neater.

The only thing I'd be careful of with a coupling from the States is the lack of the Australian Standards number. The problem would arise if the coupling failed in any way and caused an accident resulting in injury or a fatality.

Yonnee

Thanks very much for the offer of help. The trailer is going to be for a saltwater boat. I was going to get it hot metal sprayed as I have been informed that this method is 10 times better than hot gal dipped. Im using Al-Ko axles. Would it help to find out the center of gravity from my naval architect who designed the boat for the placement of the axles?.

Stu

Love your work Yonee. I have to rebuild the work trailer except Im going for an Aluminum box tray to reduce the rusting out.

Thanks autogenous, love doing it.

* Why do people leave out the 2nd 'N'?? It's such a simple name, even has a meaning in some dictionaries (spelt with an 'IE')...
*


Stu, (BTW, my 8yr old son would love your user name. He reckons potty humour is the funniest thing!)

I'll take your word on the hot metal spraying, but I can't see it getting inside the tubing as gal does. Probably pay to look into it further.

As for the centre of gravity, might be handy, although if the trailer chassis is parallel and you get the "Marine" brackets on the AL-KO's, then you can slide the axles back and forth to get the ideal coupling weight.

...just a thought...

If you are able to get the centre of gravity measurement, then you can keep this area clear of cross rails that get in the way of axle placement and adjustability.

Hi Im only new on here, im about to start building my own trailer and was wondering where i should put the axel. should it go in the centre or just behind? im going to be making a 7x4 aluminium trailer. i will make the draw bar about 1500mm long. anything else you can help me with?

By the way yours looks tops

Josh

Hey Josh,

Thanks, and Welcome.

The standard rule for box trailers is for every foot of body length (7' in your case) the axle is placed 1/2" to the rear of centre (3.5" in your case).

1500mm from the front of your front cross rail is a good drawbar length.

Hope this helps,

Yonnee.

Awesome thanks Yonnee but i don't understand the 1/2" 3.5" thing

does that mean i put the axle 3.5 inches behind halfway?

Thanks

Originally Posted by Yonnee

...for every foot of body length, the axle is placed 1/2" to the rear of centre.

7' x 1/2" = 3.5"

Originally Posted by potter24

does that mean i put the axle 3.5 inches behind halfway?

You got it!


And that's the centre of the box, or tray part of the trailer, not overall!



Yonnee.