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Stufart
15th Apr 2008, 04:19 PM
I’m building a boat trailer for my new sport fishing alloy boat which I have almost completed. I can see why some charge what they do, its dam hard work. Anyway, my boat is a 7.3 meter centre console. It’s made from 5083 H116 alloy construction. The boat will in at around 1500kg as a hull with engine and full of fuel. For the trailer, I have gone with main chassis rails of 158mm by 50mm by 3mm rolled steel. My mate who supplied me with this steel uses the same rail in his production car carriers and bob cat trailers. The cross members are 50 by 65 by 4 mm wall RHS. I have cut and welded the cross members as you can see, in one or two of the photos you may have noticed some gaps, the cross members are the same length its just the side rail which has a bit of a kick out in it. I can almost pull this in by hand so I’m not worried.

I have to cut the angles at the front where the chassis will meet the draw bar. I’m going to put heaps of reinforcing around this area. This is the first trailer I have ever built, I’m thinking maybe a I bitten off a bit more than I can chew but then again if I go slow and make sure every thing is over built and true I should be ok……god help me. I figure if I keep progress reports going every day or two on this forum I should be pretty much ok. The boat I built myself and I’m hoping the trailer shouldn’t be much harder. Please, if you see some thing im doing wrong or about to, please scream at me.

Stu

Fossil
16th Apr 2008, 08:49 AM
Hi Stu,

Sorry I can't help with advice regarding the boat trailer. I have built a few trailers, but never one for a marine craft.

Good on you for giving it a go though. You may be able to pull the side rails in with a rope or strap while you weld it up.

The boat looks good. Where did you get the design? I was intending to build one like that many years ago. I was looking at getting all the ally supplied cut from a mob in WA. The cost of it put me off though.

Stufart
16th Apr 2008, 11:56 AM
The boat sis a custom design the naval architect and Myself put together. Adam Schwetz is the guy who designs not only small boats but also ships and masive passenger ferries. The alloy is in fact cheaper to by like this than one sheet at a time of in bitz and peices. My alloy come in at 1200kg with a bit of waste. It works out around 40% cheaper to build it yourself than to buy it off the shelf so to speak.

Stu

2sub
17th Apr 2008, 12:38 PM
Your project looks great. What sort of welder do you use to weld aluminium with?. Thanks

Stufart
17th Apr 2008, 04:24 PM
The welder is a Uni mig 270, which has so far been very good, "touch wood". I have heard some people bag them but I personly havent heard of anyone that owns a Uni Mig that has problams. I would love to get a Fronius pulse welder, I have used them on alloy and man are they sweat to use. The only thing I didnt know until I got home with the welder was it needed a 20 amp plug. This was a problam because all houses are only 10amp. I had to get a 20 amp switch fitted to the house, no big deal realy.

Stu

sabian631
17th Apr 2008, 08:55 PM
with the trailer make sure you put plenty of drain holes in all the low points and have a hollow draw bar. if you can get the whole thing hot dip galved. also you may need to get trailer brakes, we do in s.a.

Stufart
17th Apr 2008, 11:13 PM
As for the draw bar, I was going to go with 150 by 50 by 6mm. This should be ample to support the weight. Im going to put a bit triangle shaped checker plate over the draw bar section to lock it all in place. As for gal dipping, Im going to get some prices on that.

Stu

2sub
18th Apr 2008, 01:16 PM
A pusle Mig would be good but very expensive to purchase. Do you know a rough cost to buy one ?. Have you any close photo of the weld using MIG. I have used Mig to weld on small aluminum project but not very happy with the result. Thanks.

Stufart
18th Apr 2008, 05:05 PM
I will have to a few for you mate. What thickness are you welding?.

Stu

Yonnee
18th Apr 2008, 06:30 PM
As for the draw bar, I was going to go with 150 by 50 by 6mm. This should be ample to support the weight. Im going to put a bit triangle shaped checker plate over the draw bar section to lock it all in place. As for gal dipping, Im going to get some prices on that.

Stu

That size drawbar will be OK, I was wondering when the first pics showed a piece of 50mm sq at the front. When you do fit it, make it extend back past the join of the main chassis rails for 600mm to a metre and then weld in a cross rail at this point. It will give it more strength. Have you decided on what brakes to run? You're going to be close to the limit for requiring breakaway, which is 2000kg GVM, if you can get the trailer around 500kg.

Stufart
19th Apr 2008, 04:37 PM
Yonnee

That piece of 50mm was just to see if the angles I had drawn where close. I figured the draw bar would need to go back into the frame by about a meter. I was then going to use the same size RHS to use as the cross member. As for the trailer coming in under 500kg, I think Im going to be pushing you know what up hill. I have Al-Ko Axles which need disk brakes for.

Stu

Yonnee
19th Apr 2008, 11:31 PM
And where do you mount the chickens? I haven't seen them used on a trailer before! Some kind of reversing beeper? Or maybe a depth guage... when they stop squawking,...

Stufart
19th Apr 2008, 11:38 PM
Great ideas for the chickens mate. It was pooring down all day here so the chickens move in under the shed for protection.

Stu

Yonnee
19th Apr 2008, 11:59 PM
Sorry...

You say your axles need disc brakes as if you've already got them. If you have, could you post a pic of them so I can see what setup they've put on. You are on the right track with discs for boat trailers. Give Melbourne Trailer & Caravan Supplies a call for a price on their Electric over Hydraulic brake unit. It mounts on the trailer, is a fully legal breakaway system for hydraulic brakes, and is controlled from the tow vehicle by any standard Electric Brake Controller.
The AL-KO version of this, the Sens-A-Brake, only works as a package. The only way to control the trailer part of the Sens-A-Brake is to have the other part fitted to the tow vehicle (part of which is a pressure sensor fitted to the brake pedal).
I don't know about anyone else, but something foreign attached to my brake pedal doesn't fill me with confidence. And my automotive background tells me that pedal pads wear. How expensive is a replacement pedal attachment going to be, if they even sell it separately?

Looking good Stu.


Yonnee.

Stufart
20th Apr 2008, 11:02 PM
I have the Al-Ko axles sitting here at home. They are second hand froma mate and need sand blasting. There in pretty good condition and has only light rust, no real deep stuff. I cant complain as he gave them to me as he was up grading his trailer with new leaf springs. The axles suite are for ford, I think I will ned to replace the brackets that hold the calipers onto the axles. As for the brakes, I very confused about this whole side of the trailering game. I cant see Electric being very good in a salt water environment. I money is getting quite low now so Im getting a bit worried about the breakaway system costing. :C

Stu

Yonnee
20th Apr 2008, 11:36 PM
Get me some pics, if you can, of the current caliper brackets.

Your biggest drama is going to be weight. Even a kilo over the 2000kg GVM mark will put you into the breakaway catagory.

It seems you're not familiar with the new(ish) Electric over Hydraulic system. The main unit is bolted to the front of the trailer and is basically an electric pump. Controlled by the Electric Brake Controller from inside the tow vehicle, it then provides variable hydraulic pressure to any form of hydraulic brake, drum or disc. Also contained in the unit is a battery and a separate switch, which in the event that the trailer parts company from the tow vehicle, the switch pulls apart, providing full battery power to the pump and applying the brakes.
The beauty of the Electric/Hydraulic unit from M.T.C.S. is that it has all the advantages of electric brakes from a towing and braking point of view, and the benefit of running marinised disc brakes for better saltwater longevity. You can also use this system with any brake controller, so anyone who has a controller (with the right sized vehicle) can legally tow the boat, whereas with the AL-KO Sens-A-Brake, only another vehicle with the same system fitted could tow it. Great for security (although if someone's going to knock it off, they won't be worried about brakes), but not good if you're stuck somewhere.

Hope this helps.

Stufart
21st Apr 2008, 04:22 PM
Yonnee

Dont laugh to loud mate, these axles are second hand and need sand blasting. I will then get them hot meatl sprayed which will make them last for years. I also noticed on one of the plates that the holes dot quite line up, Im wondering if I should just cut them off and weld new ones on? As for the electric brakes, will they work out more expensive than the normall breakaway system. I dont know much at all about brakes on trailers so its all a bit new to me.

Stu

Yonnee
22nd Apr 2008, 03:06 PM
:rotfl:


Sorry...

From what I can see, the inner brackets were possibly for another set of rims. The little 9" alloy wheels you see on alot of boat trailers are too small to allow calipers and disc rotors to tuck inside the rims, so there's a different set of brakes for these that the rotor has a long snout which places the disc part of the rotor and caliper beside the wheel and tyre. My guess is that someone has put 14" wheels and tyres on with standard rotors, hence the second caliper bracket. They don't need to line up with each other as they are not used together.

It also looks like you have "Slimline" bearings too, which with non load sharing suspension, will give you a carrying capacity of 2400kg on those axles.

The electric system is a normal breakaway system, and probably the most cost effective. Until the Electric-over-Hydraulic system was developed, the only other way of running a breakaway system with hydraulic brakes on the trailer was to set the tow vehicle up with either a compressed air system, or a vaccum system, both of which require major additions to the tow vehicle and were in the vacinity of a couple of $K plus labour. The Electric/Hydraulic part for the trailer should be around $1500 and a controller in your car start at around $100 plus fitting for a good one. (Beware the controller brought out by a reputable towbar manufacturer, IT'S RUBBISH) I'm not going to name names here, just covering my 'backside'.


I dont know much at all about brakes on trailers so its all a bit new to me.

Mate, that's what I'm here for.:2tsup:

Yonnee.

Stufart
22nd Apr 2008, 04:18 PM
Yonnee

Is the $1500 plus $100 all I need to spend on brakes or is there more to it than that? Im glade I dont have to cut those brakets off the axles that would could be a messy job. I have older ford alloy rims, will the rims fit over the calipers or do the rims sit away from the disc and calipers to some degre? The brakes, rims, axle set up is far more complex than building the trailer. I thought the trailer was going to be the hard part as it turns out, its the rolling stuff that is the headach.:yikes:

Stu

Yonnee
22nd Apr 2008, 06:35 PM
The headache is getting all the clearances right.

The $1600.00 is the tow vehicle and breakaway side of it. You'll still require the brake kits themselves for each axle. And your rims should fit over the calipers, same as your car ones do. I say 'should', as some alloys are thicker than the normal steel rims and their offset can make them a tight fit, but you shouldn't have any problems.

Have you made the trailer to suit the axle mounts? And what mounts are on the axles? You only showed me a picture of the swing arms.

Y.

p.s.
If you look at it this way, spend the money now on the right gear for the trailer and it will last you alot longer, and do a better job than a cheaper alternative. You can scrimp, but yours, and others safety is at stake when it comes to braking nearly 4500kg of boat and tow vehicle.

Stufart
22nd Apr 2008, 08:41 PM
Yonnee

Thanks mate, No way Im going to scrimp on the braking side of things, just needed to know what Im up for. I will have to post up another pic of the axle mounts. I have built the trailer to suite the axle mounts, they sit right in the middle of the mounts, 1445mm that way I can easly get the U bolts on with out any trouble what so ever. Is there any extra bits I need for this breakaway sytem that fits onto the breaks on the trailer or is it just the disks and calipers?. Buy the way is that $1600 from the company down in Vic, if so thats heaps cheaper than up here in QLD. I have had quotesw of over $2500 for the airtank type.

Stu

Yonnee
22nd Apr 2008, 10:32 PM
Well don't "quote" me on the price, I have a four year old price list, but give them a call, 03 9772 2333. They supply axles all over the place, and it shouldn't cost you more than $100 to freight it from Melb. to Sunny Coast.

For the record... You need;
1 x Electro/Hydraulic unit (H1600 for disc brakes) (http://www.dexteraxle.com/electro_hydraulic_actuators)
I'm pretty sure the kit sold by Melbourne Trailers has the breakaway kit included. Even for those under 2000kg, it's still a good way to have "Electric" Disc brakes.

1 x Electric Brake Controller for tow vehicle. (Tekonsha, Kelsey or Dexter recommended)

2 x pair hydraulic calipers, disc rotors and bearing kits. (Here the spacing of the holes in the caliper mount brackets will determine whether you require PBR or Trigg calipers.)

4 x Flexible brake lines and enough bundy tube to plumb it all up.

And that's pretty much it.

It sound like you've got the mounting of the AL-KO's sorted, my only concern is if you're going to 'U'bolt them (best way for adjustability), you'll need to brace the 'C' channel along this point or you'll collapse your chassis rails by tightening the 'U'bolts.

Y.

Stufart
22nd Apr 2008, 10:45 PM
Up here in QLD e need 4 calipers or one on every wheel for trailers over 2000kg. Will a standard caliper be ok or do i need a special type of caliper to fit the electric system. When you say electric disk brakes do you mean that literally or do the calipers hook up to normal hydrolic hose with fluid and then that goes up into some electric pump system? What is bundy tube? As for bracing the C channel I was going to use some 6mm plate the entire lenght of of where the U bolts will be situated.

Stu

Yonnee
22nd Apr 2008, 11:25 PM
Up here in QLD e need 4 calipers or one on every wheel for trailers over 2000kg.
As does the rest of Australia.


Will a standard caliper be ok or do i need a special type of caliper to fit the electric system.
The standard caliper that bolts onto your existing mount will be fine.
There are two main options in the trailer industry. They run different bolt spacings and won't interchange.


...do the calipers hook up to normal hydrolic hose with fluid and then that goes up into some electric pump system?
Got it in one!:2tsup: That's exactly what the Electro/Hydraulic system is. A system to control hydraulic brakes on the trailer with an electric controller in the tow vehicle. It also allows the hook up of a battery and switch as a breakaway system.


What is bundy tube?
Sorry... the tube the brake fluid runs in. Can be either steel or copper, although copper is not legal in some states.


As for bracing the C channel I was going to use some 6mm plate the entire lenght of of where the U bolts will be situated.

Stu
Cool!

wtrueman
23rd Apr 2008, 02:29 AM
What suspension are you going to use? If leaf springs, make sure you can mount so you can shift up or down the length of the trailer in order to get a good tongue weight at the ball hitch but a weight that you can still move yourself when unhooking from the tow vehicle. Wayne

Stufart
23rd Apr 2008, 11:12 AM
Wtrueman

I will be using Al-Ko axles, like or much the same as tor axles. Yonnee, Im now with it mate:;. By the way, how much weight should be on my tow ball? My boat trailer will weigh around the 2100kg mark maybe 2200kg. I have had heapes of differing opinions on this matter, some say 10% of total weight, others say so you can pick the trailer up at the tow point. I dont like the idea of being able to pick 2200kg boat and trailer up by myself, means there is stuff all weight on the tow ball, things could get bad out on the highway. :o

Stu

Yonnee
23rd Apr 2008, 03:28 PM
Yeah, the 10% figure is usually the one thrown around, but I beg to differ. 10% might be a good rule of thumb for most single axle caravans that weigh between 800kg and 1500kg, but these days with so much variety in trailers, most ideal towball weights need to be assessed on a case by case basis. One thing people don't take into account is the wind loading on a trailer at 110km/h. A tall trailer can seriously lose all its ball weight at that sort of speed (even though the stationary ball weight might be quite high), and the next thing you know the tail's wagging the dog and trying to drag you off the road. Suspension can also have an effect; load-sharing versus non load-sharing.
For yours, I'd be aiming for 120kg or so. But having said this, be careful of some cars towing capacities that limit ball weight maximum to this, even though their actual towing capacities may go close to 2200kg.

Stufart
29th Apr 2008, 07:03 PM
Ok, I have welded the drawbar on but haven’t yet welded the cross member on. This was a nightmare doing this on my own. The drawbar is 1800mm long by 150 by 50 by 5mm wall. This Is all I could get on the whole Sunshine Coast. I have one concern with the drawbar though, over the length of the trailer the drawbar is ¾ inch to one side. I have 1 meter of drawbar hanging out past the welded “A” frame section of the trailer. I’m really miffed because I hate things that are out more than 5mm. I’m going to put a couple of sash clamps on hr in side of the drawbar to see if I can pull it over a bit. I suspect that I can make the adjustment when I put the axles on though. The other Idea I hade was to place the coupling a bit further over than normal.:doh:

Stu

Yonnee
30th Apr 2008, 10:39 AM
72433

You could try this, if haven't welded the cross rail in at the back of the drawbar.
(I hope it's clear enough)

Stufart
30th Apr 2008, 06:50 PM
Yonnee

I ran two string lines along each main rail; I then measured from those points to the middle and then come to the disgraceful conclusion the drawbar is in fact 40mm to the left of the photo. I was going to cut the right hand section right off and then bend the left over a bit utilizing the cuts as you mentioned. Not Happy Jan.:doh::~

Stu

cfish
30th Apr 2008, 09:33 PM
Nice looking boat there Stu I’d love to d a similar project if the shed my sded was bigger. I’m sure the trailer will turn out OK but there are a few minor problems there . It’s a bit late to change now but if the rails have gal coating most people will want to charge you extra to acid strip it off before it goes in the zinc, the other thing is you need venting holes or the cross members will explore or if there is zinc trapped inside your end up paying for it. You can fix these problems with a lot of drill holes but you might to read http://www.corp.indgalv.com.au/technical/manual.htm (http://www.corp.indgalv.com.au/technical/manual.htm)
and check out how some factory trailers are built, their made the way they are to deal with the galvanising issues.
Regards Charles

Yonnee
1st May 2008, 01:03 AM
LOL, Now you know why Dunbier and MacKay trailers use a jig for their boat trailers. At least you've found out now rather than when close to being finished.

But I do feel your anguish.


Y.

Stufart
1st May 2008, 12:28 PM
Im not angry anymore, just miffed that I let it happen. As you said, at least I found it now rather than when its all welded up. I hate re doing things, going over the same ground twice. I suppose thats how we all learn when we do things ourselves. Its the first trailer I have built little lone welded in steel. As for gal, I dont know yet mate, I dont think I will get it gal dipped. I was looking at hot metal zinc sprayed. Lasts ten times longer but they may not be able to get in to the hard to get at places like gal can. I recone gal would cost me a mint to get this trailer dipped, not that the cost is a big issue. I was also looking at hammer paint, whats your thoughts on that fellas.

Stu

Stu

Stufart
1st May 2008, 05:57 PM
OK, I spent half a day straigtening the drawbar and by the looks of things I have it right. I ran two straight lines downb each side of th emain rails and then one up the guts of the trailer. I measured 100 times until I had it spot on, actually 1mm out to one side. See if it looks straight to you guys.

Stu

Stufart
4th May 2008, 06:16 PM
The trailer is coming along quite well now. Im finally happy. Their is a few things I havent finnished like the coupling mounting plate. I think it should be plenty strong enoungh.:;

Stu

Yonnee
15th May 2008, 12:39 AM
The trailer is coming along quite well now. Im finally happy. Their is a few things I havent finnished like the coupling mounting plate. I think it should be plenty strong enoungh.:;

Stu

I thought you said this boat weighed 1500kg... not 5100kg??

Must have been a typo.:2tsup:


So... those gussets on the coupling mount plate... adding some ball weight to the front are we?:;


:q:q:q:q

Fossil
16th May 2008, 12:11 PM
I recone gal would cost me a mint to get this trailer dipped, not that the cost is a big issue. I was also looking at hammer paint, whats your thoughts on that fellas.

Looking good Stu,

Hammer paint will last for about a week after you first dip her in the
water. (I am assuming salt, by the design of your boat)

I know the cost $$$$ will hurt a lot, but sand blasting and then hot dipped gal is the only way to go for a boat trailer. If you paint it, it will be next to impossible to blast the paint from the inside of joints when you find that you will need to get it dipped, which will hurt more than getting it dipped from the outset.

jatt
23rd Aug 2008, 01:09 PM
The boat trailer that the boss and I built was painted in hammertone earlier this year. So far so good. Obviously it is hard to beat hot dip gal tho.

This trailer was designed to accomodate a fold out camper on top. When one arrives at the river its simply a case of back into the water as with a conventional trailer and unload the boat into the river. The camper unfolds off the side of the trailer as per most designs on the market.

basically the boss didnt want to have the trouble of manually lugging the boat and motor around once he got to the campsite.

The latest project we are doing is a horse float. Its almost complete. If u want a challenge, have a go at building one. Seen some folks use em as a furniture van as well.

Got a Unimig 240. The only prob I had was a connecter came loose near a contactor inside the box. Place I bought it from found the prob in minutes and I was back in action the next day. The binzal torch on it is quite ok for a cheap unit. Best thing is can get spare parts easily. As most would know, the torch cops a lotta abuse. Fortunately mine only needs a 15 amp plug.

sconly
23rd Aug 2008, 08:52 PM
hey stu nice hull there is it you design or one of a plan the reason im asking is that i would like to make my own i have had a bit of exp weldiny allo and have a fronius 2700 transpulse
cheers:2tsup: