rogerthebodger
Well-known member
As for wheel bearings on trailers that get dunked just replace the existing steel ball bearings with stainless steel equivalents.
Thanks Yes It sounds similar to plant trailers which have a bed able to be moved up and down to load and unload plant without steep ramps.Kneeler suspension is when the trailing arms and springs can be pivoted up to drop the frame.
Way back, when Lotus sold Elans as kits, they came out of the factory on a sort of bedstead, sans suspension and engine/gearbox. This then needed several blokes to manhandle onto a trailer for delivery.
We built them special trailers which had no centre structure, just side members. Four wheel independed suspension with Aeon rubber springs. Two of the wheels could be jacked down with hydraulic rams to lift the car off the bedstead, then back down and driven away. One guy, the driver, did this and there was a space up front, with a hoist for the engine etc. Client was told to supply something to reverse the process at the far end. Mr Chapman was most impressed when we demoed the first one.
For the boat, the the system could be similar, just lowering the frame rather than raising it. But prob easier to put the channels low and use ramps. I can get them under a foot off the ground with out complex framing.
Yes Will, I take your point, but I need a well maintained braked trailer for travel on the M5 and other trunk roads like A30 to Cornwall. The brakes are also degraded and it worries me that one day the bearings or the brakes may fail. That prospect is something I want to avoid at all costs never mind the safety issue there is the inconvenience and cost of getting the whole thing back to base.Well I have been dunking my trailer in water for 40 years. I won't say it has been maintenance free and I confess the brakes were removed long ago. The back half of the chassis has been replaced. However I do not find it onerous to jack it up and "do" the bearings virtually ever dunking. But in my case I don't tow it very far and when I get there the ramp (you call it a slip) is reasonably steep so yes the bearings go under but only just. (reminds me I must do the bearings right now) I also only launch and retrieve once per season. But I still reckon OP would be better off putting his energy into maintenance of a dunking road trailer. ol'will
What about brakes though, you need them legally for towing weights above 750kgAs for wheel bearings on trailers that get dunked just replace the existing steel ball bearings with stainless steel equivalents.
Thanks John, that sounds interesting, yes I have come across Bearing Buddies before I think you can get them in UK but you don't mention brakes. They are also subject to corrosion. It is illegal to tow without braked trailer over 750kgIn NZ and Australia it is easy and cheap to buy hub stubs and bearing kits for boat trailers. There are legions of trailered power boats and a good few trailer yachts like mine.
These hubs have marine seals and when used with Bearing Buddy or similar dust caps are effectively waterproof. I submerge mine every time i launch and retrieve my 7.8 metre trailer yacht and haven,t changed a wheel bearing for at least 4 years of regular use. The trailer has to pass roadworthy inspection each 6 months and would fail if bearings were at all compromised.
Link here for example: https://goughtwl.co.nz/images/products/TWL Light Trailer Parts Equipment Catalogue 2015 2017 Update.pdf
Surprised you cant buy similar in the UK?
As for trailer structure, stainless is wonderful stuff but comes with its own problems such as fatigue cracking and cost.
I built my trailer out of open channel section mild steel and had it shot blasted and zinc sprayed. (Its a long way to the nearest zinc dip bath.) two years on i am still happy with the result.
You could do the same with the angle iron trailer in an earlier post and it would most likely be a lot cheaper than Stainless steel.
Yes I am aware of the stainless fatigue issue but the launching trolley will only be used for a short time but I do wonder if it would be subject to fatigue when loaded on to another trailer as a 'piggy back' trailerIn NZ and Australia it is easy and cheap to buy hub stubs and bearing kits for boat trailers. There are legions of trailered power boats and a good few trailer yachts like mine.
These hubs have marine seals and when used with Bearing Buddy or similar dust caps are effectively waterproof. I submerge mine every time i launch and retrieve my 7.8 metre trailer yacht and haven,t changed a wheel bearing for at least 4 years of regular use. The trailer has to pass roadworthy inspection each 6 months and would fail if bearings were at all compromised.
Link here for example: https://goughtwl.co.nz/images/products/TWL Light Trailer Parts Equipment Catalogue 2015 2017 Update.pdf
Surprised you cant buy similar in the UK?
As for trailer structure, stainless is wonderful stuff but comes with its own problems such as fatigue cracking and cost.
I built my trailer out of open channel section mild steel and had it shot blasted and zinc sprayed. (Its a long way to the nearest zinc dip bath.) two years on i am still happy with the result.
You could do the same with the angle iron trailer in an earlier post and it would most likely be a lot cheaper than Stainless steel.
Have you considered disc brakes with a disc made from stainless steel.What about brakes though, you need them legally for towing weights above 750kg
Thanks yes I am aware of disc brakes.Have you considered disc brakes with a disc made from stainless steel.
thanks for the info, I have never weighed it but others say that the Privateer 20 say it is over a ton when you add the trailer itself to the total weight The road trailer will need brakes. I do try to wash the trailer after immersion but facilities are often lacking at launching sites. You can drill a hole in the brake drum backing plate and wash out the brake drums internally. It just seems to me though that this is closing the stable door after the horse is gone. The sea water has already started to do its damage. To me the long term solution is not to immerse the road trailer in salt water. It doesn't make sense to immerse the road trailer in a corrosive liquid. Yes The picture of the new Tyrone Nelson trailer is built with a central channel for the jockey wheel and a 2 wheel trolley system and you winch the trolley up some short ramps and the wheels of the trolley sit quite low down quite near to the road trailer wheels. This way the C of G quite low on the road trailer and this maintains stability. Unfortunately Tyrone Nelson went into liquidation last year. This design is not available from a commercial supplier as far as I know. I think Bramber do a piggy back trailer system. Other trailer manufacturers like Dehler and Hunter use 4 wheel launching trolleyLocal friend does a lot of T/S ing with his little gaff cutter. I usually change both wheel bearings on a yearly basis. Cost about €60 EACH from the trailer bods, less online. They are 'sealed' angular contact ones.
More interestingly, while the trailer is galvanized, the square in square 'indespension' type suspension was not on the internal square tube and after seven yrs they rotted and failed. The trailer was never immersed down to that level, but splashes and general salt atmosphere was enough. No brakes, as under the limit.
Just one further thought about flatbeds. If there is doubt about the point load on one not aimed at carrying wheeled loads, then perhaps get some channels folded up and fixed with a frame to the trailer (if borrowed/rented) or just bolt them through. The dolly I have planned will be 1.80 x 1.20mt. with the front pair steerable, using plastic wheels with plain bearings 4x8" (wheelbarrow type) rated at 200kg each, already in the boat shed..
Yes, I used a boatyard in Cornwall where I was lifted off the road trailer ( to avoid submersing the road trailer) onto a slipway and waited for the tide to come in as you describe. It worked ok until we put the anchor down to sort ourselves out and promptly fouled the anchor on some mooring chains on the river bed! That was a another story though.My Sonata came with a launching trolley. In essence the normal cradle for onshore storage is on wheels and can be winched on and off the road trailer. In practice at low tide (it is fin keel) offload boat and trolley onto slipway. Wait for tide to float boat off, recover trolley. Reverse for recovery. The trolley can be very basic, but will add weight - check your towing weight.
thanks for your reply and your experience what was the weight of your boat?Back in the last Millennium I bought a 16 foot Contender dinghy, it came with a wooden trailer! Basically hard wood fence rails, steel u bolts and some steel plates at the gooseneck. To say I was sceptical was an understatement. It was the best trailer, left natural no one in their right mind would steal it. One day a bearing virtually seized, off to the bearing shop and the assistant commented "never had anyone replace their wheel barrow bearings"!! We found box trailers rust out, so wheels and axles readily available and very cheap. Waterproof bearings and the occasional lick of paint, maintenance done. This trailer did thousands of motorway miles and was last seen heading for Tasmania from Sydney. Don't rule out timber it only has to go up and down a ramp.
OK thanks my boat weighs 750kg so quite a bit heavier.Peter, my Contender was probably less than 100 kgs - the trailer was probably heavier. But you are only on the ramp. The setup virtually balanced so the towball had about 5 kgs on it. For construction it was just layers, the axle on the bottom with springs,, next the longitudinal stringers, then the boat supporting frames, gravity working for you. If you are only going around the boatyard and into the water I would keep it as close to the ground as possible needing the least tide to float off. You could use a crane to lift off the road trailer onto the wooden trailer and take your better one home, believe me no one will steal a wooden trailer!! Cheers from Down Under.
A lot of sense in that.I fear that youre making things very complicated for yourself. I look after 4 trailers which spend much of their lives sitting round doing nothing and they all need a couple of hundred quid spending on them every year to keep them roadworthy. That includes, brake systems, bearings, jockey wheels and electrics. They are never immersed but not used enough to stop things slowly getting gummed up and failing. So unless your road trailer is used frequently, say once or twice a month throughout the year, I’d expect you to need to spend time and money on servicing the thing.
Given the servicing costs and the hassle that entails, I’d tend to opt for the simple life with a trailer which you use to both transport and launch. Accept that before driving down to visit us you need to service the thing: take the wheels off and check bearings (replace them if you’re worried about their condition, doesn’t take long and bearing are cheap), make sure the brakes are working, check the electrics, jockey wheel and hitch. Carry the tools and spares needed to change a bearing or brake shoe. So much simpler to my mind than going to the expense and hassle of building a launch trailer.
Final point. Any launch dolly you use will need to be able to sustain the G forces imposed by the boat as a load during towing. That’s one of the reasons why the commercially available systems are expensive, as the whole road trailer/launch dolly combination has to be constructed to meet the regulations as a whole. Constructing a dolly to put onto a flatbed trailer and then taking the combination down the M5/A30 isn’t a trivial challenge. If memory serves me correctly, the cradle needs to be able to withstand 2-3 G fore and aft and 1.5-2 G side to side and vertically. So for your one tonne of boat, your cradle/dolly will need to be able to accept loads of 3 tonnes or so fore and aft and 2 tonnes side to side. Vertical load resistance is mainly done via lashings but the support keeping the boat vertical also need to be substantial. You should talk to an engineer about this sort of stuff before committing any money to what may not be a viable concept.
That's all good if you only ever want to launch at the perfect slipway.There is no need for dipping wheels, brakes etc. when launching from a standard trailer.
In my case - much lighter boat, a Drascombe Dabber about half the weight - I reverse on the slip until trailer tyres are just touching water. The trailer end overangs shallow water. .......