Littlehamton winter shore storage £22.50 a week - craning in the Centaur - £90 -

[Blueboatman]

The rubbing strips on that age of Westerly are 2" x 1" teak, through bolted (1/2" UNF bolts) every 6" or so. A vertical lift would make no difference at all that I can see; the straps would still go round the hull and over the rubbing strips on their way up. The only difference is that the inwards force without spreader bars would help push the rubbing strip more firmly against the hull and resist the shear force better.

Nope. Without spreader bars and with an impacting vector load, any movement of the slings as they take up the strain is applied vertically at the contact face to the teak. You can usually see it as shinier, scuffed or polished or abraded areas on the wood . ( strain being elongation as we both know). Why do it?

1/2in bolts @6in centres? Nowt is going to actually tear out eh?

 

[Seajet]

Blueboatman,

I'm afraid experience does not bear out your worries; plenty of Centaurs and a wide variety of other boats were craned out at my club with never a spreader bar in sight; they are not necessary if the slings are long enough.

This was twice a year for every boat from about the early 1950's to the time the EU decided mobile loads on cranes were a no-no and we bought a travelhoist.

Never a problem once including some old underbuilt wooden boats.

 

[JumbleDuck]

Nope. Without spreader bars and with an impacting vector load, any movement of the slings as they take up the strain is applied vertically at the contact face to the teak. You can usually see it as shinier, scuffed or polished or abraded areas on the wood . ( strain being elongation as we both know). Why do it?

I really don't think that a very slight change to the direction of the force applied above the rubbing strip is going to make much difference here. Anyway, it's with spreader bars that any sling movement will be mostly vertical at the rubbing strip. without them it will be slightly inwards at the top. I suppose you could use spreader bars to wide that the straps don't touch the rubbing strip at all, but they would have to be very wide indeed.

1/2in bolts @6in centres? Nowt is going to actually tear out eh?

Sorry, my mistake. 1/4" bolts, or possibly 5/16" (it's been a while). Still pretty damn tough.

 

[JumbleDuck]

This was twice a year for every boat from about the early 1950's to the time the EU decided mobile loads on cranes were a no-no ...

When did that happen? And please don't tell the yard till they have launched my boat again ...

 

[Searush]

Very bad practice to lift a boat like that. The boat could have been crushed, usual way is to spread the load so that the strops hang away from the sides of the boat. Lucky that the Centaur is strong.

Dont forget to add...: That 200kg will be applied to the wooden rubrails. Those strops stretch a tad . Which means there is now a tearing -or shear if you like- force applied to the rubrails' fastenings ( prob alloy rivets glassed over on the inside and as old as the boat).
A vertical lift via spreader bars would allow stretch without friction applied to the wood and fasteners..

Because it is not visible dont mean its not ' there '

Ah well, job done

Nope. Without spreader bars and with an impacting vector load, any movement of the slings as they take up the strain is applied vertically at the contact face to the teak. You can usually see it as shinier, scuffed or polished or abraded areas on the wood . ( strain being elongation as we both know). Why do it?

1/2in bolts @6in centres? Nowt is going to actually tear out eh?

Blueboatman,

I'm afraid experience does not bear out your worries; plenty of Centaurs and a wide variety of other boats were craned out at my club with never a spreader bar in sight; they are not necessary if the slings are long enough.

This was twice a year for every boat from about the early 1950's to the time the EU decided mobile loads on cranes were a no-no and we bought a travelhoist.

Never a problem once including some old underbuilt wooden boats.

There will be another 30odd boats lifted like that by mobile crane at Caernarfon at the end of the month, including an elderly folkboat. It will be happening all up & down the country thoughout the spring (just as it did last autumn). Can anyone point to an example of damage caused to an otherwise sound boat? I've never seen a problem in over 30 years of watching boats being craned in & out, mostly by mobile cranes with long strops but without spreader bars. Then there is the fact that the vast majority of the Westerly range is built like a brick shithouse & almost uncrushable, even if leaned on by a trawler.

I'm impressed your club has a travelhoist, Seajet, but their reason for buying might just be different than you think.

 

[chewi]

Can anyone point to an example of damage caused to an otherwise sound boat? .

On camera on Quest TV.
A famous northern heavy lifting firm took the rowing boats off the deck of HMS Victory after their gung-ho operators made out they had done it all by now.
I braced myself for the uncomfortable consequence, and as expected the lack of either spreaders or deck beams squashed the first boat.

A carpenter quickly fabricated a compression strut to stop that happening to the second one.

The fact that it doesn't happen more often seems to be a fortuitous testament to the strength and style of the typical boats rather than the skill of the cranemasters.

We use spreaders on all our boats at my club.

 

[emsworthy]

Nice! Did you get to keep the fancy blue polyprop mooring lines too? layful:

 

[bluerm166]

The ability to resist crushing forces depends on the construction of the hull and its ability to distribute them.Jeanneau specifically forbid lifting without spreaders on certain wide beam modern open plan type hulls and having owned such it makes sense that with a thin grp 'shell' outer hull strengthened by a bonded inner floor pan the last thing that you want is undue flexing that could separate the two.I also witnessed a delivery pallet loaded with kee-clamps crushed just as it got craned to second storey roof height.(yes,it should not have been used).So despite also making the calculations of the reduced inward force you get with long strops I also made my own shaped end spreaders of paired scaffold planks to lie between the strops.I don't need the planks any longer because I bought a British boat.

 

[Seajet]

Jumbleduck & Searush,

our club always hired in a mobile crane for lift in & out, traditionally all the club cruisers go in or out of the water over a period of about 3 days.

That was until roughly 15 ?? years ago, the message was that having a load while the crane moved is now verboten.

As it's an all volunteer club there was a whip-round between members and we bought a tractor driven travel hoist - and a couple of tractors, one pretty good one and a slightly tatty Plan B.

The hoist is worked off the hydraulic take-off and as well as lift / lower it can adjust its' width and allow tilting back or front, ideal for fitting new keels to Anderson 22 's !

A few of the regular team at the club have trained themselves to operate the thing, looks like playing an organ to me but touchwood they do very well; I'm surprised more clubs don't have one but then we concentrate on this sort of thing and gladly go without paid staff in white tunics !

View attachment 40944 View attachment 40946

 

[EuanMcKenzie]

some cranes are designed to drive with a load hanging such as an iron fairy & some are not

The law asks for planned lifts etc in accordance with LOLER but i don't think specifically bans moving cranes if they are designed for it

That said you'll need spreader bars with an iron fairy as the jib needs to be low for stability when minoevering so maybe it just didn't work

 

[Seajet]

We always used Marsh Plant mobile cranes; they were big machines and the guys knew what they were doing but it was sometimes a bit fraught with boats swinging around, it was common to see the members on the hanging bow & stern lines being dragged along trying to dig their heels in to prevent the boat contacting the jib.

 

[prv]

The law asks for planned lifts etc in accordance with LOLER but i don't think specifically bans moving cranes if they are designed for it

Presumably the ones the club formerly used were not designed for it. The scheme worked fine in practice, but once bureaucracy got involved they found they couldn't justify it on paper?

Pete

 

[Searush]

Some interesting extra details coming out now.

I can understand the need for a travel lift if you have been driving cranes with a 5-10 ton load dangling off them. Our Harbour Trust uses a large stabilised crane capable of picking up, swinging & dropping in the water without moving. That has also been the practice wherever I have seen boats craned in elsewhere.

And craning open boats like whalers with only rowing thwarts for cross bracing is very different from a monococque (sp?) GRP hull with internal bulkheads designed to resist the forces applied by mast & rigging.

Mind you I'd expect a decent sailing Admiralty style Whaler should still be pretty strong if in good condition, they would be designed for picking up or dropping over the side while the parent vessel was still sailing & releasing or attaching strops with spacers might be fun. I'd assumed they would have single attachment points on the stem & stern posts, I must go & look it up in one on my old C19th sailing manuals.