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winston
12-01-2011, 08:33 PM
My mate and I (together) tried to lift the drawbar of my boat from the ground. The boat is a 5.6 m plate half cabin with a 140 Suzuki on a single axle trailer. I thought that the two of us could have lifted this. So, we moved the axle forward 12.5 cm, however we could still not lift the drawbar (we had to return the axle to its original position since the brake arm would now contact a trailer crossmember). I should add that I had a full tank of 150 L. I rang the dealer who said that this was normal i.e. not to be able to lift the drawbar. He also noted that it is not unusual in boats above 5m to have to use a trolley jack to aid placing them on a vehicle. I thought that about 10% GVM should be on the drawbaw and two men should lift this. where to now? Thanks Winston.

FishHunter
12-01-2011, 08:36 PM
I cant lift mine either, my car hardly sags it tows fine so I am not losing any sleep over it.
I also read in one of the boat magazines that more towball weight makes the rig more stable, up to a point obviously

fisho64
12-01-2011, 08:58 PM
lighter on the drawbar makes it more prone to "wagging the tail" to the point of the tail wagging the dog

Raesen
12-01-2011, 09:08 PM
I'm with winston and fisho 64.... I have a Jayco hawk camper approx load 1500 kg (not a boat but a towing load none the less) rigged with boat, trailer etc on the van. Can not lift the unit but moves with ease with ALKO wheel and travels a treat under tow..

Cheers
Pete

Moonlighter
12-01-2011, 09:31 PM
Generally it is accepted that between 5 - 10% of BMT weight should be on the towbar. Lots of articles around from experienced people to that effect. As others have said, too little weight = wagging the tail.

I'd estimate your boat probably weighs somewhere around 1300-1500kg depending on how heavy built and whether its on a single or dual axle trailer, so somewhere between say 70kg and 140kg on your towbar would be ideal, subject to that not being more than your car's manufacturer prescribes.

If you dont know what the BMT actually weighs it's a very good idea to run it across a weighbridge and find out. (then compare to what your trailer VIN plate says it can legally carry - might be surprised....)

There are of course 3 ways to shift the balance in order to lighten the weight on the towbar - one is to move the axle/s forward, the other is to move the winch post backwards, or a combo of both. I suppose at a oinch there is a 4th way - to move weight inside your boat to the stern.

If you can't adjust these to mean you have the correct weight on your drawbar, I'd be wondering if your trailer is too small for your boat or something like that.

TOO MUCH weight on the towbar can be just as much of a problem as too little.

And illegal!

The problem is that all modern cars and SAA approved towbars will have a max downforce weight prescribed for them, and you can't legally exceed that.

Plus, it may simply weigh the bum of the car down too much. With independent rear suspension on most cars these days, that can result in bad rear tyre wear and other problems.

I have also seen pics of an alloy trailer in F&B mag with a 7m+ boat on it that had too much weight on the draw bar, and not only had it distorted (bent) the main draw bar, it also resulted in too much weight on the front tyres on the tandem axle trailer - tyres overheated and blew as a result.

Hope that helps

Cheers

ML

winston
12-01-2011, 10:04 PM
Thanks for your replies guys, the boat tows ok but I was quite concerned over the trailer drawbar weight. Perhaps I should have gone with a tandem trailer or maybe I worry too much. Cheers Winston.

finga
13-01-2011, 08:59 AM
What is the downward weight rating of the towbar??
It should be stamped on the plate that's on the towbar.
This rating would/should have a lot of people worried as it must be remembered it is usually only smallish bolts that hold a towbar onto the back of the car.

Sheik
14-01-2011, 12:21 AM
What is the downward weight rating of the towbar??
It should be stamped on the plate that's on the towbar.
This rating would/should have a lot of people worried as it must be remembered it is usually only smallish bolts that hold a towbar onto the back of the car.
Exactly right... check for the rating of the towbar. There should be a downward rating and a total weight allowable. So for example a little 4cyl mmight have a 70kg downward and a 700kg total whereas my ssangyong has i think 250 kg down and 2500 total.
An easy way to check what your boat weighs is just to pop bathroom sccales underneath the towball and gently place the towbar onto the scales. Make sure you have solid scales as by the sounds of it you might have well over a hundred kg loaded up. And that's true obviously about moving the trailer post backwards to put the boat more over the axle. You will find though that sometimes that can make it difficult to put a motor support bracket into the fitting on the trailer if you go back too far.
Good luck with it.
regards Jim

Moonlighter
14-01-2011, 09:58 AM
The other way to check how much download on you towbar is to go on the weighbridge and stop in a position with the car just past the end and trailer and its wheels on it.

You can first weigh the trailer when its attached to the car (that's the GTM), after that make sure the jockey wheel is also on the weighbridge, then take the weight of the trailer on the jockey wheel (that's the ATM), and the difference between the 2 is the weight on the towball.

Cheers

ML

winston
14-01-2011, 12:21 PM
Thanks Sheik, I also have a Ssangyong. I checked and the maxium download is 230 Kg. I am now much happier to know this. Cheers Winston.

Sheik
15-01-2011, 08:37 AM
Thanks Sheik, I also have a Ssangyong. I checked and the maxium download is 230 Kg. I am now much happier to know this. Cheers Winston.
Yeah mate they don't look much but they can carry a fair load...must have decent little coils there. Yours a diesel or petrol? How do you rate it? I love this little beast. Diesel SUV 2 litre goes real well. trade in price is the only problem...

winston
15-01-2011, 02:16 PM
Shiek, mine is a 2008 Kyron 2L diesel auto. Very pleased with it so far but does need a new set of shocks as the original ones are too harsh. I lowered the drawbar gently onto my wifes bathroom scales but stopped at 120 Kg, therefore it has more download than that. Cheers Winston.

Sheik
17-01-2011, 08:35 AM
Shiek, mine is a 2008 Kyron 2L diesel auto. Very pleased with it so far but does need a new set of shocks as the original ones are too harsh. I lowered the drawbar gently onto my wifes bathroom scales but stopped at 120 Kg, therefore it has more download than that. Cheers Winston.
OK. Mine goes quite well, and only pulled a 485 Stacer (when I owned a boat) but did it easy. It's a great little motor the 2L diesel, just time will tell how the rest of the car stands up to things. So far so good.

Kevaclone
18-01-2011, 10:10 PM
With both my trailers I can lift the front of the trailer easily enough, I'm guessing about 40kg over the ball, but I can also climb into the rear of the boats and not have the trailers tip up, even bouncing on the transom(I weigh 115kg) so I'm guessing even my 5.8m plate boat with 90 merc doesn't weigh much. I did however move the trailer axle back 3 inches but I might move it back some more.


It tows very well at 110 but it didn't have any gear onboard. full tank of fuel(150L mostly forward of the axle) and some eskys should put enough over the front to make it quite stable at speed

winston
18-01-2011, 11:06 PM
Moving the axle tomorrow, I will have to move it at least cm forward to clear the trailer crossmember. I was told today that each 30 cm of axle movement forward will reduce the drawbar load by 50 kg, therefore I expect a reduction of approximately 60 Kg . I also have to add 20 Kg for the spare wheel and tyre located on the drawbar. This should do it. I will let you know of the outcome. Cheers Winston.

deckie
18-01-2011, 11:27 PM
I know we like to do stuff ourselves, but i'd be using a good trailer guy. An experienced one would just get it right straight up and not cost much.

Kevaclone
18-01-2011, 11:53 PM
undoing two Ubolts and using the suck it and see method is hardy a time consuming deal, even moving it a couple of times to get it right should only take an hour, took me 10 minutes to move mine the one time

winston
19-01-2011, 07:48 PM
Success at last (almost). I took my boat to my local boat yard this morning, they moved the axle forward 35 cm (I was dropped off on the river in the boat) and boy o boy did that make a difference. I could and did move the axle myself with the help of a mate , but did not have the gear to lift it high enough to clear the trailer crossmember. The rig tows so much better and safer. I probably need to move it slightly more forward as it still tops 120 Kg , however this is very easy for my mate and me to do. Very pissed off with the dealer at this stage for assuring me that it would be set up correctly. p.s. $110 to rectify. Full review of BMT to follow soon. Cheers Winston.