Trailer Upgrade to Dual Axles

[boleropilot]

G'day youse mob, I have good news and bad news - after some serious number crunching on the new outfit I have decided to upgrade the trailer on 'the outfit' to dual axles. Main reasons relate to safety, I just don't think the trailer is as good as it can be considering the driving we will be doing chasing those finny thingos all over S E Qld. Plus we live on a road that is partial dirt - every time we go in/out we do 8km of potholes that are getting bigger every day. And a lot of the bitumen roads are in terrible conditions after all the rain, which is why I am leaning towards roller rocker springs.

Luckily I have a good mate who lives nearby with significant engineering skills - he has got the job of doing the work. After getting the outfit/car weighed, the next step will be to hit the books for all the relevant numbers for the new dual axle suspension. Then it's just a matter of sourcing all the replacement parts. The old axle, brakes and wheels/tyres will be sold on, and the trailer moved to the workshop to add the new components. We reckon it would be a right royal pain in the khyber to do the work with the boat still attached to the trailer, so the BIG question is simply how to remove the boat from the trailer while the work is being done.

I have an excellent workshop with a Happ 4000kg car hoist, so I am wondering if anyone has any experience with using one of these lo lift a boat up off a trailer. It seems to me that two heavy duty straps (1,000kg minimum) attached to the four arms of the hoist would do a perfect job of lifting the boat a few inches off the trailer, moving the trailer from under the boat, then carefully lowering the boat onto soft material. Those two main straps would be connected to other straps to avoid the main straps from slipping forward or backward.

Hoping ya's can give some advice here, I intend to take photos of the entire process and post it all here.

Regards,

BPasset.jpg

[disorderly]

Just tie a rope to one of those trees in the background of the photo and tie it to the 2 rear cleats on the boat, get a few tyres ready and place them against the hull as you slowly drive forward and drop it off the trailer onto the tyres...saves tying up your hoist for the trailer build period as well..


..

[Mopheus]

By all means use your workshop and hoist with slings if that suits you, but I've dropped my 16' hull on the grass out the back a half dozen times while getting the trailer set up right and doing some other work. I didn't even use tyres - just straight onto the fairly thick buffalo grass and packed beneath the chines at the transom with some scrap timber.

The main thing is to disconnect the trailer from the car when winching it back on, so that the trailer is winched under the boat rather than the boat onto the trailer. That avoids any belly rash.

With respect to your planned work, I didn't think roller rocker suspension was particularly well suited to corrugated roads? Have you considered a single HD torsion axle instead?

[boleropilot]

hey thanks Mopheus, I will definitely check out the option of the HD torsion axle option. I just checked out the prices for lifting slings at good old Bunnings, no problem there, cheap as chips...

the reason I was going for the roller rocker option is because there is a lot of stuff on the hinternet thingy that says they are very good for rough roads and a smooth ride - more reading to do methinks

BP

[gunna]

Never done it myself. But after 30 odd years of seeing this question asked across different Forums, the answer has always been to do what Disorderly said.

[Dignity]

Never done it myself. But after 30 odd years of seeing this question asked across different Forums, the answer has always been to do what Disorderly said.

And another for this method, to retrieve it I don't disconnect the trailer, just take the vehicle out of gear and brake off it will roll back under the boat. I've done it on my own.

[Mopheus]

And another for this method, to retrieve it I don't disconnect the trailer, just take the vehicle out of gear and brake off it will roll back under the boat. I've done it on my own.

Depends on weight and friction - I had the outboard off and the ~450kg hull was still dragging while I had the car attached. Rolling resistance of the car + trailer on thick buffalo was higher than sliding resistance of the hull once the bow was up on the rear rollers. Just try out of gear first and unhitch if necessary.

[NAGG]

Some kind of lubricating spray on the rollers or skids doesn't hurt either

Chris

[boleropilot]

The Nova is an '86 model, so no doubt built like a brick shisenhousen (I think that's the German word I'm looking for). One thing I have discovered is that public weighbridges are few and far between away from high population areas - I'm gonna take my boat for a 'fishing trip' via the Scenic Rim Council Refuse Station (which I am authorised to use)...entry there is via the weighbridge !

BP

[Dignity]

The Nova is an '86 model, so no doubt built like a brick shisenhousen (I think that's the German word I'm looking for). One thing I have discovered is that public weighbridges are few and far between away from high population areas - I'm gonna take my boat for a 'fishing trip' via the Scenic Rim Council Refuse Station (which I am authorised to use)...entry there is via the weighbridge !

BP

Done that myself, generally they won't let you unhitch the boat but see if you can get a reading with the vehicle as it comes off the weighbridge so just the boat is on there. You'll be able to work out virtually everything if you have weighed the vehicle previously. I also use a towball weight stand that gives me the towball weight, pretty cheap to buy, often on special at the auto stores for well under $100, not that accurate but worthwhile using as an unloaded boat and a loaded boat can have significantly different towball weights. Doing offshore trips of more than a day I carry up to 80 kg of ice (should look at a portable fridge freezer setup) and where this is loaded can change the dynamics greatly, let alone all the other gear I carry.

[gazza2006au]

G'day youse mob, I have good news and bad news - after some serious number crunching on the new outfit I have decided to upgrade the trailer on 'the outfit' to dual axles. Main reasons relate to safety, I just don't think the trailer is as good as it can be considering the driving we will be doing chasing those finny thingos all over S E Qld. Plus we live on a road that is partial dirt - every time we go in/out we do 8km of potholes that are getting bigger every day. And a lot of the bitumen roads are in terrible conditions after all the rain, which is why I am leaning towards roller rocker springs.

Luckily I have a good mate who lives nearby with significant engineering skills - he has got the job of doing the work. After getting the outfit/car weighed, the next step will be to hit the books for all the relevant numbers for the new dual axle suspension. Then it's just a matter of sourcing all the replacement parts. The old axle, brakes and wheels/tyres will be sold on, and the trailer moved to the workshop to add the new components. We reckon it would be a right royal pain in the khyber to do the work with the boat still attached to the trailer, so the BIG question is simply how to remove the boat from the trailer while the work is being done.

I have an excellent workshop with a Happ 4000kg car hoist, so I am wondering if anyone has any experience with using one of these lo lift a boat up off a trailer. It seems to me that two heavy duty straps (1,000kg minimum) attached to the four arms of the hoist would do a perfect job of lifting the boat a few inches off the trailer, moving the trailer from under the boat, then carefully lowering the boat onto soft material. Those two main straps would be connected to other straps to avoid the main straps from slipping forward or backward.

Hoping ya's can give some advice here, I intend to take photos of the entire process and post it all here.

Regards,

BPasset.jpg

Have u looked at minimum eye to eye spring weights usually they are designed for big loads and going tandem you may have too stiff a trailer on the lightest springs

I used 600kg leaf springs on my tandem trailer once the hull went on it was only just ok not sometbing i would tow down a rocky road or one of those bumpy outback roads up north QLD

[Dignity]

The single torsion axle setup does not offer weight equalisation and therefore not suitable for heavy loads, rough roads or off road work, sick to the roller rocker suspension.

[Volvo]

Whichever way you go once you alter the original trailer you will have to get the alteration certified legally..
Had to do so with my caravan..

[disorderly]

Whichever way you go once you alter the original trailer you will have to get the alteration certified legally..
Had to do so with my caravan..

Good point Volvo..

When I imported my dual axel Chinese trailer it had to be inspected , measured up and certified by a HVRAS inspector before it was able to be rego-ed..

Even though it was brand new everything from axel spacing, load sharing and rating, tyres etc were measured and inspected to be sure they complied...

Probably best to make sure that its even do-able first before spending time and money on the existing trailer...

Its possible you may find it easier to sell the current trailer and buy or build a dual axel one from scratch..

[Volvo]

if one decides to get a new trailer rather than do up the present one (Homework re cost done prior mindyou) , i was in a simillar position when i had my reef Boat though my trailer at that time needed work galore so decided on buying a Newy..
really got the head down n bum up searching and ended up buying one from Hervey Bay made by a mob called "Sydney Trailers" for a third of the cost of what some others were asking and not a badly made Trailer either .
Tandem offcourse , though dont know if those Trailers are still available as i had a hunch thee might have been a tad of Chinese in them ??, though was told they were made here in godd old Asiieland,.
Trailer was still Spik when i sold the Boat so had no reason for complaint ey..