"Barge falls off trailer"

[cuthound]

17 minutes ago, Murflynn said:

no trailer is safe to tow if the weight distribution is wrong, regardless of the towing vehicle and compliance with the weight restrictions.  I found my boat trailer had a tendency to fishtail on the motorway at 55mph if disturbed by a passing truck, although the nose weight on the towing ball was well adequate.  I cured it by removing all the moveable weight from the back of the boat to the back of the car (outboard, anchor, fuel and water containers).  

Very true, I once specified the generator set for some 100kVA mobile generators when working for BT and project managed the build and roll-out to the field operatives. BT Fleet specified the trailers they went into. The whole shebang weighed 3500kg so that it could be towed by a Land Rover Defender, and deployed by local field people. Previously the largest mobile generator they could tow was 44kVA.

As the rig was on the legal limit for towing I insisted that the field operatives passed a specialised towing course before being allowed to take them back with them. 

In the first week two turned over, so I put a ban on them until we had found out what was going wrong. Various theories were put forward, including being disturbed by the draught when overtaken by LGV's and 7.5 tonners (which can legally do 70mph on a motorway).

To get to the bottom of it, I booked Bruntingthope vehicle proving ground, and took the trailer designer, a 42 tonne artic and a 7.5 tonne van from BT Fleet.

Turned out that BT Fleet had specified a 50kg nose weight (more appropriate to a caravan), and this was the cause of the instability, especially when subjected to the side draught from a fast moving large vehicle, exacerbated by the official advice to slow down when the trailer starts snaking. (We found it was better to accelerate hard to pull the trailer straight, and then slow down when it had stopped snaking).

The fix was to move the axles back a couple of notches (there were bolt holes for several positions), to increase the nose weight to 150kg, the maximum permitted for a Land Rover Defender.

Interesting work, which took me a long way from comfort zone, but learnt a bit about trailer design and towing, as well as having a go at  towing and driving the artic.

 

[cuthound]

33 minutes ago, Murflynn said:

it's only about 15ft long in that picture.  

Must have been shortened as a result of the accident 

[Mac of Cygnet]

The first thing that occurred to me was what was it doing there anyway?  The Caledonian Canal is unsuited to narrowboats, with substantial waves possible on the lochs. Or can Sea Otters really cope with this?

[haggis]

8 minutes ago, Mac of Cygnet said:

The first thing that occurred to me was what was it doing there anyway?  The Caledonian Canal is unsuited to narrowboats, with substantial waves possible on the lochs. Or can Sea Otters really cope with this?

Sea Otters have slight V bottom which make them a wee bit more stable than your normal narrow boat. Although we have cruised our Sea Otter, Gamebird, the length of the Caledonian canal  we had agreed that there was no way we would cross Loch Ness unless the forecast was favourable. On the morning we were due to cross, the forecast was for the wind to pick up after 4 hours and we reckoned that was enough for us. Also we had arranged for a grp boat which moored up there to be our escort  so we set off. It went well although we were glad that we were nearly at the other end when the wind did pick up. Not really narrow boat country ad Scottish Canal don't encourage narrow boats up there.

 

Haggis. 

[bigray]

4 hours ago, Ray T said:

Whoops duplicated by me.

 

Topics now merged.

[Amber34]

Interesting post on facebook. 

 

I've hidden the name of the poster, but still unsure whether this is allowed. I'm sure I'll be edited if it's not

[LadyG]

And it seems owner was not a risk taker, having blacked the bottom, though in my ignorance, I thought that Sea Otters don;t need paint!

[DHutch]

2 minutes ago, LadyG said:

And it seems owner was not a risk taker, having blacked the bottom, though in my ignorance, I thought that Sea Otters don;t need paint!

Sea otters need paint all over, and good paint, else they become a sacrificial anode to anything steel.

[tree monkey]

9 hours ago, Murflynn said:

no trailer is safe to tow if the weight distribution is wrong, regardless of the towing vehicle and compliance with the weight restrictions.  I found my boat trailer had a tendency to fishtail on the motorway at 55mph if disturbed by a passing truck, although the nose weight on the towing ball was well adequate.  I cured it by removing all the moveable weight from the back of the boat to the back of the car (outboard, anchor, fuel and water containers).  

I've had it happen to me once, badly loaded trailer and I fishtailed wildly across the Flint bridge crossing the river Dee.

It was one of the scariest things thats ever happened to me, I had no training and no idea how to cope, completely out of control swerving over two lanes, no idea how I stopped it but luckily I did.

To this day I am obsessive about towing and how the weights loaded.

 

[Simon (Hawksmoor)]

Here is a fascinating YouTube video showing how bad weight distribution can impact trailer stability

If this link does not work Search YouTube for "Trailer weight distribution"

 

Edited July 29, 2017 by Simon (Hawksmoor)

[Sea Dog]

^^^^  I've never seen that so well illustrated; a revelation in under 30 seconds. 

On a purely selfish note, as one who far too often has travel disrupted by destroyed caravans on the A38 in Devon, this should be compulsory viewing for anyone with a towbar.

[DHutch]

11 hours ago, tree monkey said:

I've had it happen to me once, badly loaded trailer and I fishtailed wildly across the Flint bridge crossing the river Dee.

It was one of the scariest things thats ever happened to me, I had no training and no idea how to cope, completely out of control swerving over two lanes, no idea how I stopped it but luckily I did.

To this day I am obsessive about towing and how the weights loaded.

 

I too have had it happen once, put the kitcar in its trailer backwards so the engine was at the wrong end. With driver it has a near 50;50 distribution, so we're only talking 80kg being 2ft behind the centreline not infront, which isn't that much when you're talking a total size of 1200kg and 12ft.

However be that be, it made all the difference and when the speed crept slightly above the limit on a mild decent on the A50 I got what felt like all eight wheels squealing and we took up both lanes for a a moment.

Suddenly learnt what people meant be accelerating out of it, as with my foot planned on the accelerator, we where still slowly down rapidly while also applying a mild and correcting forwards pull. 

 

3 hours ago, Simon (Hawksmoor) said:

Here is a fascinating YouTube video showing how bad weight distribution can impact trailer stability

If this link does not work Search YouTube for "Trailer weight distribution"

 

Really good that isn't it.

 

Daniel

[Neil2]

IIRC those little grp Wilderness boats are towed "backwards" on their trailer, presumably for this very reason.  Most boats will be tail heavy, difficult to offset the weight of the engine in a Sea Otter especially as there's no ballast and I would think to keep the overall weight down to 3500kg you would have to empty the water tank?   

[haggis]

15 minutes ago, Neil2 said:

IIRC those little grp Wilderness boats are towed "backwards" on their trailer, presumably for this very reason.  Most boats will be tail heavy, difficult to offset the weight of the engine in a Sea Otter especially as there's no ballast and I would think to keep the overall weight down to 3500kg you would have to empty the water tank?   

We tow with the water tank and calorofier both emptied and as much weight removed form the boat as possible

haggis