Yacht Yard Trolley

aitchem

aitchem

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Hi folks,
I am looking for constructive comments on my yard cradle design, I have to bite the bullet with this one.

YardTrolleyChassis.jpg


Imagine the blue beams with indespension units under and a tow coupling at the front.
The member sizes will have to be lightened, as it comes in currently at just under 1 tonne.
I will work out the main members deflection in the office Monday, they are modelled at 200x90 PFC.
My idea would be that the keel would sit on removable round bars, this would enable a keel drop should that unlikely event occurr.
The pad supports are shown as 80x80 SHS with 60 SHS running inside.
Comments, Suggestions.?

thx
Howard
 
Some thoughts

1. Do you really need Indespension units for a yard trailer? It seems an expensive option to me.
2. I'm trying to remember how the Indespension axles fit onto my trailer but, if the load is carried on the blue beams it will need some good welding
3. Would it be worth looking at Acrow props for the pads?

I'm not sure what size your boat is but my trailer, which is road going, has an all up weight including suspension and wheels of 600kg (boat 25 ft, 2+ tonnes).

I like the idea of the removable bars. I want to drop my keel and am trying to work out a way to prop the boat up, drop the keel and then wheel the trailer out from under the boat. I'm sure it can be done, but I do feel a bit nervous about doing it!
 
I had a trailer with Indespension units which just sat around for 99% of the time. The elastomeric filling hardened up under the load (about a ton) and that meant new inserts after three years. Unwanted trouble.

Why have flexible axles ? Why not put on bigger tyres and let them absorb any bumps and ruts - it works on farm trailers up to twenty tons..

Very neat drawing BTW - Ain't CAD wonderful for seeing components groups !

Don't forget some drain holes in tubular or rect. cross section members, or rust will eat through in twenty years time. :)

The positioning of the axles seems influenced by road trailers Would it be easier to put the wheels at each corner, with a swivelling axle at the front ? Like this platform trailer on Ebay ?

http://cgi.ebay.co.uk/Heavy-Duty-St...ailers_Transporters_Parts&hash=item27b8787740

It would give you a much tighter turning circle.
 
You don't mention what weight of yacht?

Anyway, I was wondering about the suspension units. The problem with having the removable bars is that when you put the weight on, you're loading the longitudinal channels in torsion (and they're lousy in torsion)! Even if a bit of twist doesn't bother the yacht or the cradle, I can see it pinching the round bars such that they wouldn't come out.

Also, I wonder what effect it would have on the yacht itself? The structure looks quite weak in torsion down its length because the longitudinals are so close together. If you're towing it over uneven ground, I don't know what it would do to the yacht hull as it twisted.

I think I'd be tempted to move the longitudinals to the outer corners (even if it means ditching your bar idea) - OR having additional longitudinals down the sides, but obviously, weight is a consideration. That said, so what if a yard trailer weighs a couple of tons? It's not like it's going on a public road behind something with a limited towing capacity!

I think I'd also be inclined to put the wheels as close to the props as possible - even it it meant having to make the front pair castor.

Lastly, if there's any possibility whatsoever, of the boat "rolling" forwards or backwards on those bars, you'll need to brace the hull supports fore-aft as well as laterally.
 
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If you are going to be able to manoeuvre it around corners the two "axles" need to be practically as close together the wheels will allow.
Also important to get their position right relative to the centre of gravity. I'd also want the axle cross beams to be continuous lengths not just short bits welded on the sides.

You don't need suspension for a yard trolley only for road use.
BUT
I'd definitely move the axles towards the ends but then if you want to do anything other than go in a straight line you will need to make one axle steerable.

I think you will need some means of locating the boat correctly length ways but remember if its a bow post/support you need to locate it to allow for the gradient of the slipway


I'd advise you to discuss your plans with the boat yard that will be expected to use it. I think you'd be told what to do with it if you came into the yard where I'm based with it!
 
3 tips:
Keep the axles under the centre of gravity (keel) for ease of turning and to lessen the beam sizes, not at the trailer ends
Use short acrow tubes inset into tube inserts at the upper support ends so the pads will rotate and orient to hull curvature. Pins in the acrow holes for height adjustment.
Use tractor type bottlescrews for easy lateral support angle adjustment.
 
I am about to start on a yard trailer. 3.5ton boat. Two off rear axles off Renault Master, fairly close coupled with one steerable, no suspension (why?). Side props, 'acro' types braced sideways and fore & aft. The boat is a motor sailer with .85mt draft, long keel. When I get a bit further I will put up a pic.
 
I would use rectangular tubing.I would also want to know where the C of gravity of the yacht was to place the axles.The axle bearers I would place under the longitudinal pieces.Unless you can get a second hand commercial axle I would use indispension units as they are reasonable in price,to what you get.I would also place the longitudinal pieces further apart.I had a 2.5 ton cruiser many years ago and bought a 4 wheeled trailer for it.(It had been used on a "Coronet") It never looked" right to me",so I fitted another axle on it.It travelled OK on the road,the tyres coped OK with the wind up.To get the trailer in the drive we had to manoeuvre it by hand so I would take one set of wheels off.I am sure my neighbours used to dread me bringing it home, as they helped manoeuvre it.I had the trailer 10yrs and had no trouble with the indispension units,in fact the 4 originals were probably older.I used to tow it about 22miles twice a year behind a Transit van with a piano in the back! but thats another story.
 
From experience with several other people's own-built yard trolleys - including for heavy 35' Ferro' boats - I'd definitely say put the wheels towards the corners and you will need one end steerable - the ones I've seen use a lorry front axle, the actual steering by a long bar either pulled / leant on manually or pushed by a tractor.

Even a 22' boat on a 4 wheel road trailer is an absolute pig to try to manouvre at close quarters, pushing and pulling the tyres sideways - and the ground will probably be rough too.

I'd say Acro's are worthwhile to the point of essential.

I agree the longitudinal members need to be more widely spaced re. torsion.

Rigger Mortice,

What size boat ? There are several Anderson 22 lift keelers at my club, including mine.

I winter my boat on high trestles at the club, so fortunately do not need a yard trolley; however a friend alternates between taking his boat home on a trailer one winter, then leaving her on trestles the next.

One winter when he had the boat at home a problem came up meaning a season out of the water, so he ( being a good engineer ) adapted his standard road trailer to allow raising the boat on the trailer Acro's to permit keel maintenance.

Puffintrailermod90029.jpg


As I say I don't know what size your boat is, a fairly large Southerly at the club managed it by having the club hoist lift the boat a foot or two on substantial chocks, then digging a pit; this was obviously far from ideal.

I once enquired with Hayling Trailers about having a custom trailer made. As you'll know, the problem with standard road trailers is that the axles run right where one wishes to lower the keel; I proposed stub axles and a removable 'tray' for the keel, and large hull support pads.

They were quite happy to do this, but my house has a tight crooked entrance with high walls; when I asked the trailer people for some guidance as to whether I could get the trailer in or not, the helpful answer was " buy it and find out ".

I didn't fancy a £3,500 experiment, so as they could hardly bother to look up as I went in despite what would seem a good order, my money - and boat - stayed firmly put !

It does show the idea was possible though.
 
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Seajet said:
Rigger Mortice,

What size boat ? There are several Anderson 22 lift keelers at my club, including mine.
Click to expand...

The boat is 25ft long and weighs a little over 2 tonnes. I'll be able to reduce the weight to under 2 tonnes by removing everything that isn't fixed.

The trailer is blocked up at the moment.
I'm thinking of blocking the boat up at the stern and using a beam (or long railway sleeper) blocked up at both ends to support the boat just forward of the keel. I've also got legs, so I'll put them on and block them up to prevent the boat heeling over.


Then unbolt the keel, lower the trailer and (hopefully) the trailer and keel will come away from the boat and I'll be able to pull the keel away leaving the boat perched up on its blocks.

That's the theory. Doing it is another matter. My main concern is the strength of the beam which will need to be about 10ft long to allow clearance for the trailer to pass through the gap.
 
Thanks for the input guys,
I weigh in at 4 tonnes.
Although I am calling it a yard trailer, it is for wintering at home, the marina is an 40 mile each way hike which dampens the desire to do maintenance.
I have crane access problems at home (trees) so need to get the boat to the end of the 200metre drive for the bi-annual trip.
I will explore your suggestions, steering, maybe all 4 wheels.?
My initial thoughts were probably not "out of the box" enough

thx
Howard
 
Rigger Mortice,

Your idea doesn't sound unreasonable, the hull should not weigh that much when not supporting the keel.

I presume she will be stabiled laterally, fore & aft, ie the bar will have pads or something to stop her toppling ?

I have home made full depth trestles ( she draws 4'6" keel down ) and when it comes time for antifouling apply one layer, then use a packed up bottlejack.

Between hull and jack I place a 1' long wooden block, veed on it's upper surface and steel plated beneath.

I can then jack the boat up one end at a time enough to get her slightly off
the trestle, so as to move the trestle just enough to clear the unpainted area.

The keel is resting it's weight on the ground.

Obviously any trestle etc must be under bulkheads, these are suprisingly easy to locate by tapping a knuckle on the hull - assuming she's grp !

The beauty of this is that should the jack fail or something unpleasant, the trestle is still under the boat an inch or so below.

If I can help with any further description or photo's please PM me.
 
aitchem said:
Thanks for the input guys,
I weigh in at 4 tonnes.
Although I am calling it a yard trailer, it is for wintering at home, the marina is an 40 mile each way hike which dampens the desire to do maintenance.
I have crane access problems at home (trees) so need to get the boat to the end of the 200metre drive for the bi-annual trip.
I will explore your suggestions, steering, maybe all 4 wheels.?
My initial thoughts were probably not "out of the box" enough

thx
Howard
Click to expand...
So really it has to be a road trailer, and comply with all the laws relating to road trailers. That will include suspension and brakes.
I don't know if a close coupled arrangement will be suitable/ acceptable for the weight. If a true twin axle (as opposed to a close coupled) trailer is necessary then the front axle at least will have to be steerable.
Ive no idea what sort of vehicle will be needed for towing ... not the family hatchback thats for sure.

I think you need to look deeply into the relevant legislation.
It may not now be permissible to build your own trailer for road use and a firm of trailer builders may not be prepared to put their name ( required by law I think you will find) on a trailer they did not design.

You may be better off with a professionally purpose-designed and built road trailer which the marina can lift the boat onto.

A useful site is http://www.ntta.co.uk/

(But to get the comment in ahead of the smart asses it does not consider trailers for long indivisible loads like gliders)
 
Ok, it's a different game now that it's use includes road and a GWT of >5tonnes.

I suggest that you are better off buying a used small step frame trailer, which has all the lights, test certs, hydraulics / air etc., and then modifying it to provide supports.


They do come up on ebay from time to time. e.g. http://shop.ebay.co.uk/i.html?_nkw=...trailer&_osacat=0&_trksid=p3286.c0.m270.l1313


and there may be one for sale privately already set up for a boat.

R31/32/34 Trailer - Single axle articulated truck trailer with cradle for Rival 31-34. Plated for 10 tonnes. Loads of work done to electrics and brakes - have the receipts to show. Very good condition with very little rust. This trailer would require testing prior to using it on the public highway. Now £1000 or near offer. Ideal if you want to put your Rival in your drive. Contact me for pictures: tristanmortimer#gmail.com or tel 07818 040057 (22/03/10)
 
Agree with the above, build a 5th wheel trailer, or buy one and have a local owner driver haul it each way. I'm in the process myself, of building a 8250Kg 5th wheel rig for moving boats up to 30' long and 4500Kg. Even then, I may have to go to 12000Kg There are a few single axle artic trailers around that can be modded. The cost of steel alone is going to make it expensive from new. Certainly if your unit attracts police or vosa attention you'll be pulling it with a push bike for six months. A 50mm ball is normally 3500Kg MAM. With a 4500Kg boat, and 1500Kg of trailer,your hanging 6000Kg on it. A big pickup truck with a fifth wheel in the back is still not going to handle it. Forget indespension units, the wheels and stubs will rip out at that weight. Solid axle, on steel springs and a nato ring coupling, tow it with a Fastrac Get a ford cargo chassis from the truck breakers and start there, rails and rear axle already fitted. Put a drop well in for the keel.
 
aitchem said:
Thanks for the input guys,
I weigh in at 4 tonnes.
Although I am calling it a yard trailer, it is for wintering at home, the marina is an 40 mile each way hike which dampens the desire to do maintenance.
I have crane access problems at home (trees) so need to get the boat to the end of the 200metre drive for the bi-annual trip.
I will explore your suggestions, steering, maybe all 4 wheels.?
My initial thoughts were probably not "out of the box" enough

thx
Howard
Click to expand...
The most manoeuvrable trailers are those with steering at both ends. Two front axles from transits or preferably lorries. These trailers will crab sideways or turn sharply. The photo gives an idea of how the steering works. The steering arm is pivoted on the front of the channel that sits over, and is bolted to, the axle; it is also pivoted on a bracket welded to the track rod. Same system both ends.
This trailer carries my 3.8 Tonne boat up a rough slip for 200 yards without problem. These are transit axles but they are near the limits of what they will carry. Lorry axles steer more easily. PS you need steel belted light lorry tyres, NOT radials.
trailer steer.JPG
 
I also read that as off road. i.e. from his gate up to the house @ 200mtrs. So no road regs. Best get a tractor to haul it. Around here, most of the farmers have smaller old tractors for the odd jobs. Still strong enough for this sort of work.

Edit: missed Alohol's post. That is exactly what I am up to, might make it a bit sleaker(:-)) and slap some paint on. The brief is to haul it up a local slip from the river and store it at a nearby farm. Bit of public road use, but highly unlikely to be noticed (or commented on) by the local Gendarm, esp if we do it out of working hours.
 
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