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Capt. F. E. Peera
8th May 2012, 10:14 AM
Can GUN TCKLE be used to discharge/load 10 ton wt with 5 ton SWL derrick. never experienced before.

Capt. Peera

Ivan Cloherty
8th May 2012, 11:05 AM
Well Cap'n, I wouldn't try it in Oz, NZ,or UK or other EEC countries, so legally the answer would be no, theoretically it can be done because a 5ton SWL derrick would have had a 15 ton load destruction test, but not to forget also that the derrick head blocks SWL has to be taken into consideration, also the angle of the derrick so that you dont lift the heel.

Is this something you have done, or something you want to do, if the latter it's back to the drawing board with your paralellagram of forces, but it's a good way to end up in jail if anything goes wrong

Has it been done, I've seen it done in India and Pakistan on their own flagged ships and also on Greek ships, but not ships under my control and I wouldn't have sanctioned it, always remember ten tons of feathers weighs the same as ten tons of lead when it's under the hook

No doubt you'll get more technical reasons coming your way

John Pruden
8th May 2012, 05:09 PM
yes 1 third of the braking strain is the safe working load{but stay clear}if you can.JP:p:)

Les Woodard
8th May 2012, 05:35 PM
I think you will find that the the SWL is just the same as a mobile crane's SWL. Say you have a SWL of 10 ton for a crane it will only be achieved when the boom is at its shortest and topped up closest to the crane with the maximum amount of falls in the runner. The devil in the SWL of a derrick is not in the purchase power of the running gear but in the purchase power of the topping lift. I know we used to quite regulary increase the purchase power of the runner by using a block with a hook and tying the runner to the head of the Derrick so as there where two falls of runner. All derricks where not suited to this because of the SWL factor. From memory we would know when to do this when they used to come down the accomodation shouting out doubling up on number two or some other hatch.

Ivan Cloherty
8th May 2012, 06:35 PM
I think you will find that the the SWL is just the same as a mobile crane's SWL. Say you have a SWL of 10 ton for a crane it will only be achieved when the boom is at its shortest and topped up closest to the crane with the maximum amount of falls in the runner. .



Sorry Les, but not quite true, having been supplying equipment for cranes over 25 years you will find that the only thing that equates closely to a ship's derrick, is a shorebased fixed sheerleg, as neither a sheerleg or a ship's derrick have to take tipping centres, outriggers or ground bearing loads into consideration, all other non-fixed cranes do and that is their achilles heel. Also a ships derrick is designed to have it's effective SWL available at all angles when used in Union Purchase mode where a pair of 10 ton derricks could lift a maximum of 2.7 tons in single whip.

When doubling up on Union gear to say lift 5 tons with a pair of 10 ton derricks then you would use a gun tackle (Doubling up) on each derrick. The Topping lifts on a 10 ton derrick were usually rigged for a 15/17.5 ton SWL.

If wanting to lift more than 5 tons with a 10 ton derrick you would use a gun tackle or a 2/1 or 2/2 purchase and use the derrick as a swinging derrick, using either the spare winch as a topping lift or as an inboard steam guy, when in this rig you have to be careful of the angle of the derrick, not so much because of the SWL factor but because the heel pin is liable to jump out of its socket, as a lot of derrick heels were only secured with a heavy duty split pin, very few were fitted with locking nuts, as these tended to seize up.


Others may have different experiences

Tony Wilding
8th May 2012, 06:45 PM
I am amazed at the complexity of lifting gear, all the different terms used, how were they all learnt, ? some lifts were huge just using ships gear, who decided what method to use for a heavy lift, and work out the stresses, i can see why the topping lift is very important, ,were there many accidents with gear giving way, :th_thth5952deef:

Ivan Cloherty
8th May 2012, 07:40 PM
I am amazed at the complexity of lifting gear, all the different terms used, how were they all learnt, ? some lifts were huge just using ships gear, who decided what method to use for a heavy lift, and work out the stresses, i can see why the topping lift is very important, ,were there many accidents with gear giving way, :th_thth5952deef:

Tony surprisingly few on well run ships, unless of course you really are daft enough to try lifting a 10 ton object with a 5 ton derrick then your chances of not having an accident do increase expotentially.

Heavy lifts are something else again and tipping centres have to be taken into account even on ships.

What I have been trying to do is keep the answers into the context of the original question asked about relatively small lifts, which we came across very often on general cargo ships where a particular piece of cargo just exceeded what was considered the norm for the Union Purchase Rigs on a single whip which were the prevalent rigs when us oldies were at sea. We always erred on the side of safety when it came to derrick work, no quicker way to lose your job (or your life) than having two derricks coming together at a rate of knots and damaging each other and you still have a full hold and a couple of tween decks to discharge at that hatch. Caution and safety were the name of the game and you were always kept on your toes by stevedores trying to break the rules if they were on "Piece Work" and if we were in doubt we had formulaes and our pencil and paper to work out the streses on a particular piece of gear in the rig. Like everything else in life it comes with experience no matter what your calling.

Hope above helps

Les Woodard
9th May 2012, 02:07 AM
Ivan do not be sorry mate as you pointed out I stuffed up on the information and stand corrected. That is one of the reasons I switched to rigging when I left the sea because there is always more than one way to rig a load and each way is unique to that load. Might bring up one point though. I was always under the impression that the heel that the toe end of the derrick was always called a goose neck for obvious reasons. Not trying to gain back any brownie points mate as I said we all had different ways of talking about rigs. As for mobile cranes well that was to try to point out that the maximum lift is when the load is closest to the base but should not have mixed up the two systems.

Ivan Cloherty
9th May 2012, 08:12 AM
Ivan do not be sorry mate as you pointed out I stuffed up on the information and stand corrected. That is one of the reasons I switched to rigging when I left the sea because there is always more than one way to rig a load and each way is unique to that load. Might bring up one point though. I was always under the impression that the heel that the toe end of the derrick was always called a goose neck for obvious reasons. Not trying to gain back any brownie points mate as I said we all had different ways of talking about rigs. As for mobile cranes well that was to try to point out that the maximum lift is when the load is closest to the base but should not have mixed up the two systems.

Hi Les, you are correct "Gooseneck" was the correct word and it was the word that escaped me whilst I was pontificating. Of course you are correct on mobile cranes the SWL only really applies when the boom is near vertical.

Also another fact about mobile crawler cranes is that a circa SWL 250 tonne crane has only a grabbing capacity duty of circa 15 tonnes (including grab weight). In my business of 25 years of supply equipment to contractors it was incredible how many contractors had based their expense calculations on the basis that a 50 tonne crane could handle a 12/15 tonne grab at any angle and got a bit of a shock when they found they had to finance the purchase or hire of a 150/250 tonne crane, this really affects the profit margin! you would be surprised how many did not do their homework before signing their contracts. Small cranes were ten a penny the bigger ones like hens teeth and then there was the grab, so many types not compatible with the cranes available...a different and interesting world

Bob Hollis
9th May 2012, 10:02 AM
Ivan and Les, you are both correct in that there is a heel (immovable) on a derrick which is connected to and supported by the swivel arrangement called the Gooseneck.

Ivan Cloherty
9th May 2012, 10:40 AM
Can GUN TCKLE be used to discharge/load 10 ton wt with 5 ton SWL derrick. never experienced before.

Capt. Peera

Well Captain Peera, you have no doubt read all the replies to date, what do you think?, are you going to do it?, or play by the rules to safeguard those who would have to carry out the 10t lift with 5t gear, and not even contemplate the exercise.

Whilst we are not waiting with baited breath for an answer an inkling of your thoughts on the matter would be appreciated

Les Woodard
9th May 2012, 11:14 PM
I to am interested in how one would do that lift. First thougts would be to do it very carefully.


Sounds like you had an iteresting life with lifting gear as well. As I said I was into rigging so involved with all types of gear and as you say could take a long time in the planning so that you only did it once and got it right. I know that I would be hard pressed to do the formula's now and after a while it was just knowing that caused this to happen especially when it all went metric even though it made it easier to work out. One soon learns to listen to others and accept opposing views in that game do they not.

Ivan Cloherty
10th May 2012, 08:11 AM
I to am interested in how one would do that lift. First thougts would be to do it very carefully.


Sounds like you had an iteresting life with lifting gear as well. As I said I was into rigging so involved with all types of gear and as you say could take a long time in the planning so that you only did it once and got it right. I know that I would be hard pressed to do the formula's now and after a while it was just knowing that caused this to happen especially when it all went metric even though it made it easier to work out. One soon learns to listen to others and accept opposing views in that game do they not.

Hi Les, don't think I would do it, unless it was absolutely vital to save someones life if they were trapped etc

Don't know about an interesting life, it certainly has been varied and certainly wouldn't have changed a thing, apart from my first wife dying at an early age from the "C" I have really nothing to complain about.But as my old mum used to say "Remember no matter what happens in life to you there are always other people worse off" and that has always stood me in good stead

Les Woodard
10th May 2012, 11:07 PM
The one I have always bored my kids with. I once complained about not having any shoes until I met a man with no feet. That has always put things in perspective for me.

Now duck as the incoming sayings fly.

robpage
11th May 2012, 06:10 AM
Due to a contractor who did thinking not checking I once had a five tonne evaporator to lift across a roof , he had a twenty five tonne crane booked which was ( 2005 ) 300 for the lift , Big error the 132 tonne crane required cost 1500 . The best of it is the local crane hire guys here will always advise on the lift free of charge to save later arguments . One of them gave me a "Sparrows " ( now British Crane Hire , I believe ) handbook , showing all their cranes , and radius of lifts at various tonnages . II used to favour all terrain cranes because they were more manouverable around site , but the short wheelbase severely restricted their capacity at the extremes of radius . The worst example was a lorry mounted 60 tonne Hi-Ab type crane that lifted 60 tomnnes at 1 M , and less than 20 tonnes at 2 M then 10 at 3 M , so the capacity was effectivly useless .

j.sabourn
14th March 2014, 08:07 AM
Tackles... Rigged to Advantage and Disadvantage, Rigged to Advantage was when the hauling part and the load were moving in the same direction and vice versa for disadvantage. Nearly every case of using a tackle was rigged to disadvantage, I used to wonder about this but gave up years ago trying to figure it out. Unless I have picked this up and being misinformed in which case I have had this bit of useless information gathering dust for donks in the back of my mind. JS

John Pruden
14th March 2014, 09:03 AM
weight versus radius modern day cranes weather wheel crawler or tower have built in electronic limits built in so you cant go over the radius of the load in the cab an alarm rings and the limits shut down the crane until you bring the load closer to the crane frame I spent nearly a year driving a tower crane and if you notice there are flags along the jib with safety weight limits on them? I did have one job lifting a section of a railway bridge from across a canal using sheer legs and the winch of the crane we could not get close enough for the lift we got the section onto the canal bank and cut it up it did bring back lots of rigging skills six fold purchase came in handy even the boss was lost made a few bob on that job?jp

Chris Isaac
20th March 2014, 03:58 PM
Tackles... Rigged to Advantage and Disadvantage, Rigged to Advantage was when the hauling part and the load were moving in the same direction and vice versa for disadvantage. Nearly every case of using a tackle was rigged to disadvantage, I used to wonder about this but gave up years ago trying to figure it out. Unless I have picked this up and being misinformed in which case I have had this bit of useless information gathering dust for donks in the back of my mind. JS

As far as I can recall and it has been a long time. A gun tackle and handy-billy are almost the same except that a gun tackle is rigged to disadvantage and would be most likely on a derrick hoist but a handy billy is rigged to advantage and would be put to such use as hauling in the tricing pennant on a life boat.
The reason I know is that I failed my Second Mates orals because I didn't know.
When I went back a week later to resit the orals I got the same examiner and he only asked me that one question again. I got it right, he said I would never forget it and what do you know here we are 47 years later and I still haven't forgotten.

Ivan Cloherty
20th March 2014, 05:37 PM
Wonder whatever happened to Capt Peera, did he try his 10 tonne lift with his 5 tonne derrick, was it successful, or is he laying under the load and that's why we are not getting a response, or was he after all a budding Mates and Masters examiner and was just testing us, it would be nice to know!

Des Taff Jenkins
7th April 2014, 04:31 AM
HI All.
Biggest lift I ever was involved in was a locomotive we discharged in Freemantle, If I recall correctly[ it was in 1950} it was the only bit of cargo in number two hold. We had to rig the jumbo derrick, as a JOS to me this was seamanship the bosun in charge directing the rigging most of it was already rigged and under canvas, but we had to get all the guy blokes in place and heavy duty wires out, long time ago now but oh! the memories. Thank you Capt Peera wherever you are.
Cheers Des

15259

Ivan Cloherty
7th April 2014, 06:36 AM
Des, like you I enjoyed rigging the Jumbo's and operating them, as the stevedores wouldn't touch them in a lot of ports, as you say real seamanship skills required. Don't think I would be too happy with working with one rigged by Capt Peera if his standard was examplified by is original question.