What Axle

[Andrew]

Got to build a boat launching trailer for the local sailing club. The trailer goes 100yrds max in a straight line 2-8 times per week every week, and sits in water for up to 20 minutes at a time.

The current trailer has some heavy walled round tube as an axle, and some more heavy walled round tube rotating around the axle, welded to the wheel rims to make a very crude bearing. The trailer is rotten and the axle tubes have worn paper thin.
Some of the other trailers use indespension axles but bearings give up regularly.
Due to the nature of the place routine maintenance has to be avoided.

So which would be the better option - a proper axle with bearings or the 2 bits of tube. Can you get properly sealed axles designed to be submerged for long periods?
Needs to carry about 3t and be single axle.

 

[Shovelhands]

Got to build a boat launching trailer for the local sailing club. The trailer goes 100yrds max in a straight line 2-8 times per week every week, and sits in water for up to 20 minutes at a time.

The current trailer has some heavy walled round tube as an axle, and some more heavy walled round tube rotating around the axle, welded to the wheel rims to make a very crude bearing. The trailer is rotten and the axle tubes have worn paper thin.
Some of the other trailers use indespension axles but bearings give up regularly.
Due to the nature of the place routine maintenance has to be avoided.

So which would be the better option - a proper axle with bearings or the 2 bits of tube. Can you get properly sealed axles designed to be submerged for long periods?
Needs to carry about 3t and be single axle.

A big bronze bush should do the trick I'd think ? But a bit of grease now n then would be nice
If you did that, could you fit long grease tubes, with the nipples high enough not to be in the water, so they are not rusty every time you want to grease it?

Another thought would be some nice big nylon bushes?

 

[Mur Huwcun]

A big bronze bush should do the trick I'd think ? But a bit of grease now n then would be nice
If you did that, could you fit long grease tubes, with the nipples high enough not to be in the water, so they are not rusty every time you want to grease it?

Another thought would be some nice big nylon bushes?

On the subject of nylon bushes I build a tandem bale trailer years ago. Used a 70mm piston from an excavator dipper ram as a pin and was planning on using nylon bushes intill I noticed one day while cutting new PTO shafts to length that the guard tubes were exactly the right dimensions to act as bushes!! They're still there as good as new aswell!!!

 

[Dave W]

I would've thought nylon is the way to go.

 

[Sharpy]

As above but stainless stubs and hubs with nylon bearings? The hubs would need to be stainless to stop them swelling and niping the stub.

 

[Sharpy]

Or bodge some bearings out of 4 inch gas pipe like I did on the roller.

 

[Tim G]

One of my colleagues does quite a bit of sailing and had problems with wheel bearings on his boat trailer. Apparently cured it by using a special type of grease (may have been hydroscopic grease?)

 

[Mur Huwcun]

Or bodge some bearings out of 4 inch gas pipe like I did on the roller.

Wooden bearings could be another option

 

[joe soapy]

steel on steel is very under rated for this sort of application, with a bit of use it soon gets a mirror smooth surface with very little friction.
main thing is to have the tube as close to the centre of force as possible, to avoid any weight induced camber,
we had numerus stub axle and iron bosses from old wagons and carts at one time, the wheel boss was often fitted with a handle to use as a post tamper

 

[atlas]

How big is the boat I have a ex life boat launching trailer here for sale I think it has built for a large rib to launch off a beach galvanised chassis .

 

[joe soapy]

 

[Andrew]

A big bronze bush should do the trick I'd think ? But a bit of grease now n then would be nice
If you did that, could you fit long grease tubes, with the nipples high enough not to be in the water, so they are not rusty every time you want to grease it?

Another thought would be some nice big nylon bushes?

Think that’s definitely the way forward, why didn’t I think of that?

steel on steel is very under rated for this sort of application, with a bit of use it soon gets a mirror smooth surface with very little friction.
main thing is to have the tube as close to the centre of force as possible, to avoid any weight induced camber,
we had numerus stub axle and iron bosses from old wagons and carts at one time, the wheel boss was often fitted with a handle to use as a post tamper

The wheels are in the middle of pipe at the moment, so no sideways force at all, they have lasted the life of the trailer which is painted box. Next one is going to be galvanised open section so would like them to last a bit longer.

How big is the boat I have a ex life boat launching trailer here for sale I think it has built for a large rib to launch off a beach galvanised chassis .

Its about 20ft x 8ft and weighs 2t. Often moved with lots of kit and people in it so going for 3t. Fibreglass mid engine displacement boat though so quite fragile - has to have all the supports just so.

 

[Graham Smith]

Andrew, you can get plain cylindrical bearings here http://www.igus.co.uk/iglidur/cylindrical-bearing if required. G

 

[ACEngineering]

One of my colleagues does quite a bit of sailing and had problems with wheel bearings on his boat trailer. Apparently cured it by using a special type of grease (may have been hydroscopic grease?)

Yes there is a special grease i have some. Its green and i use it on landlords atv trailer that has rubbish seals on the axle stubs.

 

[Morph]

Plenty of greases available, could use stainless bearings about 2x the price of normal. If using 'nylon' bushes make sure to get the correct material as a lot of them swell when wet. Most boats use Delrin as underwater bush material.

 

[ACEngineering]

Nylacast will have something suitable.