Thread: Boat Trailer Build

Hi Tas.

Is that 300-400kgs with motor?
And fuel. Batteries. Esky full of bait. anchors...............

I have a 17ft Haines. 5.25m plywood and fibreglass boat. 90 hp Yamaha.
Fully loaded, ready to go with 150 liters of fuel. Boat with trailer is over 1400kg.

There is a couple of pics of my half trailer rebuild here.
https://www.woodworkforums.com/f184/m...-build-137398/

Rod

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It cost me $250 to get a boat trailer frame galvanized last year, just build out of mild steel and get it hot dip galvanized. Gal steel is horrible to weld, it'll make you sick and the welds look very average.
I agree that a 5.25m boat will no way come in under 750kg with trailer, put brakes on it (surge brakes are all that's legally needed in the 750-2000kg trailer range)and they're cheap). It will save your car one day.

Hi Rod and Canvasman,

Thanks for the replies. The boat will weigh around 300 kgs (that's the weight of the ply and framing timber, with a margin on top), and I'm going to put a 50 or 60 hp outboard on the back, which will be around the 110 kg mark. I'm not sure about the weight of some of the chandlery, so let's say the final weight of the boat will be 500 kgs.

I have no idea how much steel weighs, which is why I'm trying to figure out the thickness I need. But based on the above, it sounds like I'll be well over the 750 kg mark. I'll look into the surge brakes.

I have a feeling that the hot dip galvanising will cost a bit more in Tassie (everything costs more down here!), but will make some enquiries.

So if I go with mild steel, what thickness would you guys suggest? And what shape?

Originally Posted by Canvasman

It cost me $250 to get a boat trailer frame galvanized last year, just build out of mild steel and get it hot dip galvanized.

Out of interest - where did you get it done? I've been interested in getting stuff dipped, but assumed there was nowhere around Canberra to do it.

G'day Tas,
I also agree that you wont get a decent boat on a decent trailer under 750kg. (Even if you could, cars that will eat this extra weight for breakfast un-braked without much reduced stopping performance are in the minority.)
One more vote for brakes.
While more expensive, I can think of two benefits of electric brakes: They are safer (do a search on the forum) and they discourage "mates" from wanting to borrow your trailer because their car is not wired for it.

Originally Posted by Tasmerican

From what I've read, it looks as though I should avoid choosing square/rectangular tubing.

I'd actually suggest you should avoid angle or tube, especially in structural areas like chassis rails and draw bars.



Canvasman - When building a 7x4 last year, the best quote by a long shot I could find in Melbourne was $700 for the chassis only. While dipping would have been ideal, I ended up fabricating the whole trailer from gal (Including gates, guards, sides and floor. Welds painted with cold gal. Not a hint of zinc poisoning by being careful). Would have had it dipped if the cost was only $250, though. You did well at that price.

Made a few calls about dipping today, and the best quote I could get was $800. But that's okay, because I ended up buying a trailer off of Gumtree for a song. It needs new wiring, and I'll have to set it up for the shape of my hull - but it's got brakes! They're the kind where the cylinder pushes out when the ute's under brakes, which in turn pulls some wires that apply pressure to the brake pads...not sure what the proper name for that is (hopefully someone can enlighten me!).

It's a hair smaller than 2.1 m across the outside, and somewhere around 6 m long. I'll try to post some pics over the long weekend.

The next step now is for me to figure out what to do about the wiring. I'm not sure whether the lights work or not, but was thinking about starting afresh and buying something like this:
eBay Australia: Buy new & used fashion, electronics & home d

Am I correct that - along with the above kit - I'll also need side lamps on the trailer?

If you are going to mount he lights on your trailer make sure they are submersible.

The other option is to use a "light board" to hang off the back of the boat but remove when launching.

The brakes you have are surge or over-ride brakes.

If they are disc brakes they won't rust as much as drums but will still like a good hose off after a swim in salt water.

Personally I wouldn't want electric brakes on a boat trailer as too much to rust away and cause problems.

I just replaced two axles under a mate's drum braked boat trailer where the drums had rusted to the backing plates over winter as he never rinsed them out.

Firstly, Welcome to the forum. I trust you'll find a wealth of information with a few keystrokes and mouse clicks.

Originally Posted by Tasmerican

They're the kind where the cylinder pushes out when the ute's under brakes, which in turn pulls some wires that apply pressure to the brake pads...not sure what the proper name for that is (hopefully someone can enlighten me!).

The Industry calls them over-ride brakes. Legal up to 2000Kg they come in Hydraulic and Mechanical, both in Disc and Drum. My preference for boat trailers for cost effectiveness and long term serviceability has been to recommend Mechanical (cable operated) Disc. (From your description, I gather this is what you have.) There's only two moving parts to the caliper, and the fittings should be stainless (bushes, bolts and spring), but you do need to keep the adjustment up to ensure effective braking when you need it. There's an adjuster as the pads wear, and the cable does stretch a little, so there's an adjuster at the coupling end too. It's a fine balancing act between getting the cable taught enough to have effective brakes, but not too taught they cause drag, prematurely wearing the pads and causing them to get hot.

It's a hair smaller than 2.1 m across the outside, and somewhere around 6 m long. I'll try to post some pics over the long weekend.

The next step now is for me to figure out what to do about the wiring. I'm not sure whether the lights work or not, but was thinking about starting afresh and buying something like this:
eBay Australia: Buy new & used fashion, electronics & home d

Am I correct that - along with the above kit - I'll also need side lamps on the trailer?

"Technically", over 1.6M wide you are required to have white front clearance lamps, but there is a provision in the VSB1 for boat trailers that allows them to be Red/Amber, and be placed on the mudguard. There are plenty of trailers on Australian roads, over 1.6M wide, that got registration without extra clearance lamps, but I'd rather the oncoming truck see the trailer behind me that's a little wider than my car...

Hi Guys, thanks for the replies. It's been pretty miserable weather all day, so I haven't had a chance to post pics of the trailer yet.

Zuffen, I nearly ended up going with a light board, but found a cheap set of submersible LED lights.

If they are disc brakes they won't rust as much as drums but will still like a good hose off after a swim in salt water.

The last owner didn't do a great job of keeping the discs clean, but they should scrub up fine. I may replace the pads.

Yonnee, Thanks for the tip about tightening the brakes.

"Technically", over 1.6M wide you are required to have white front clearance lamps, but there is a provision in the VSB1 for boat trailers that allows them to be Red/Amber, and be placed on the mudguard.

I'm trying to find this in the VSB1 - is it 13.8? When you say placed on the mudguard, is that on the top of the mudguard, or the outside?

I'm definitely finding this forum useful!

Actually, it's part of 13.1, but if fitted in accordance with 13.8, then you can fit a pair on the guards. And they can be either on the top or the outside. Usually on top gives the lights better protection from being bumped by walls and other cars.