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BTR69

Approximate boat weight??

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Does anyone out there have a 60ft Hancock and  Lane 1986 boat?? I am trying to get a rough estimate of the weight so I can get the right size crane to lift her out. I work in the crane industry but can’t find any information/specs on this boat.

Im sure someone on this forum must have the answer.

Thank you guys and girls

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depends on the ballast.  if the boat is average 2ft draft (measure at half length) then 20 tonnes is near enough.  pro-rata if the depth is less or more.

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Do it with displacement.  60' × 7' × 2.5' as a volume of water weighs about 30 tonnes.

 

It will be more than the actual weight of the boat, but that's helpful when sizing a crane.  Don't forget to allow for the reach though!

 

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Well my boat drawing 2' 4" at the stern and around 2' at the bows weighs in at about 18 tons. remember it is not a 57' rectangle. The swim at the bow  and stern make it more like a 45' rectangle

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Generally a 70ft boat has a draught of 1" per ton, so a 60ft boat has a draught of about 15% more than that. Measure the draught at each end of the straight sides to get the average and work it backwards from there.

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Since a cubic metre of water weighs a metric tonne it's a bit simpler to do the displacement calculations in metric even if that means you have to convert feet to metres first.

15 hours ago, TheBiscuits said:

Do it with displacement.  60' × 7' × 2.5' as a volume of water weighs about 30 tonnes.

 

It will be more than the actual weight of the boat, but that's helpful when sizing a crane.  Don't forget to allow for the reach though!

 

 

There's no way a 60ft narrowboat comes close to weighing 30 tonnes and since the limit of most yard cranes is about 25 tonnes I'm not even sure your gross overestimate is helpful.

 

My widebeam weighs about 30 tonnes and I had to hire a 100 tonne crane, but you're not going to need that for a 60ft narrowboat.

Edited by blackrose
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20 hours ago, BTR69 said:

Does anyone out there have a 60ft Hancock and  Lane 1986 boat?? I am trying to get a rough estimate of the weight so I can get the right size crane to lift her out. I work in the crane industry but can’t find any information/specs on this boat.

Im sure someone on this forum must have the answer.

Thank you guys and girls

I have a slightly earlier H & L which on the crane weighs 11.2 tonnes. It is 40' 6" in length so you can extrapolate from there!

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2 hours ago, Up-Side-Down said:

I have a slightly earlier H & L which on the crane weighs 11.2 tonnes. It is 40' 6" in length so you can extrapolate from there!

not quite, 'cos the swims at either end will be similar regardless of the length of the boat, whilst the only the central part of the hull (perhaps 40ft in OP's case, perhaps 20ft in yours) can be treated pro-rata.  And it doesn't take account of the draft and ballast.

 

irrespective of the maker of the hull, you need to measure the draft at the mid-length of the boat, and go from there.

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6 minutes ago, Murflynn said:

not quite, 'cos the swims at either end will be similar regardless of the length of the boat, whilst the only the central part of the hull (perhaps 40ft in OP's case, perhaps 20ft in yours) can be treated pro-rata.  And it doesn't take account of the draft and ballast.

 

irrespective of the maker of the hull, you need to measure the draft at the mid-length of the boat, and go from there.

All part and parcel of the extrapolation eh!

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After numerous precise displacement calcs I arrived at approx 18.5 British long tons for 60' nb Innisfree fully fitted out and loaded inc full water and diesel tanks. 

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8 hours ago, blackrose said:

 

My widebeam weighs about 30 tonnes and I had to hire a 100 tonne crane, but you're not going to need that for a 60ft narrowboat.

You might.
A lot depends on the distance the crane is from where the boat is. Remember at school studying "Moments" in physics?
https://www.bbc.co.uk/bitesize/guides/ztjpb82/revision/1

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4 hours ago, Graham Davis said:

You might.
A lot depends on the distance the crane is from where the boat is. Remember at school studying "Moments" in physics?
https://www.bbc.co.uk/bitesize/guides/ztjpb82/revision/1

Not necessarily the case if the strain gauge is reading the lift cable tension, then it doesn't matter how far out the jib is angled.

Roger

Edited by Albion
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16 minutes ago, Albion said:

Not necessarily the case if the strain gauge is reading the lift cable tension, then it doesn't matter how far out the jib is angled.

Roger

Sorry Roger the crane may well fall over

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33 minutes ago, Albion said:

Not necessarily the case if the strain gauge is reading the lift cable tension, then it doesn't matter how far out the jib is angled.

Roger

this thread is getting surreal.   :banghead:

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33 minutes ago, ditchcrawler said:

Sorry Roger the crane may well fall over

As far as the weight reading is concerned. Yes, you are correct that  the balance of the crane and the load capability of the crane is another consideration but the comment was about the weight reading and whether the moment would affect the reading.

Roger

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26 minutes ago, Albion said:

As far as the weight reading is concerned. Yes, you are correct that  the balance of the crane and the load capability of the crane is another consideration but the comment was about the weight reading and whether the moment would affect the reading.

Roger

Which is what I replied to!


 


My widebeam weighs about 30 tonnes and I had to hire a 100 tonne crane, but you're not going to need that for a 60ft narrowboat.


No mention of "weight readings".

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46 minutes ago, Albion said:

.....but the comment was about the weight reading and whether the moment would affect the reading.

Was it? are you sure?

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43 minutes ago, Graham Davis said:

Which is what I replied to!


 


No mention of "weight readings".

The thread is about the weight of a narrow boat which is what I thought you were replying to. However, if you are bringing in a scenario where the reach of the crane is required to handle lifting the boat over others to reach the water or distance to the water from the quay for example then you are correct that the further the reach the greater the crane capacity to handle that reach safely and within the load capability of the crane. The load on the cable is the same it is just a matter of the capacity of the crane at varying reaches and whether it is sufficient for the situation.

Roger

Edited by Albion
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I was always led to believe that a boat made of steel, fully fitted out with furnishings, white goods etc weighs approximately  1 metric tonne per metre length, ( give or take a little bit), ie a 40ft boat is nigh on 11 metres and will weigh approx 11 tonnes.

Also regarding the arching  of a jib relates to how far the reach is( in practicality  a 50 tonne crane can lift 50 tonnes at a distance of 1metre from the central upright point of the cranes jib, then at a reaching distance of 50 metres from the upright, it can only lift just 1 tonne without falling over or being secured in other ways to its foundations.

It was a matter of physics  I learnt at school many years ago.

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17 minutes ago, Karen Lea Rainey said:

 

....................  in practicality  a 50 tonne crane can lift 50 tonnes at a distance of 1metre from the central upright point of the cranes jib, then at a reaching distance of 50 metres from the upright, it can only lift just 1 tonne without falling over or being secured in other ways to its foundations.

It was a matter of physics  I learnt at school many years ago.

you may have learnt about moments at school, but crane ratings are far more involved than that.    you have simplified it by assuming a 50 tonne crane has a moment capacity of 50 tonne.metres, which is not correct.

 

actually many cranes have a nominal rating based on what they can lift at a radius of 5ft, which is practical inasmuch as a dense load as close as possible to the side of the crane will be at a radius of about 5ft.

 

 

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Probably not much help to you but my 40ft H&L weighs just over 8 tons i was told on the cranes scale when lifted out last year which surprised me how light she was :blink:

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1 hour ago, Murflynn said:

you may have learnt about moments at school, but crane ratings are far more involved than that.    you have simplified it by assuming a 50 tonne crane has a moment capacity of 50 tonne.metres, which is not correct.

 

actually many cranes have a nominal rating based on what they can lift at a radius of 5ft, which is practical inasmuch as a dense load as close as possible to the side of the crane will be at a radius of about 5ft.

 

 

 

Indeed.

 

I needed a 1000 tonne crane to lift a 40 ton packaged generator from the road at the side of a Docklands building and to place it in the centre of the roof 14 stories up.

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11 hours ago, cuthound said:

 

Indeed.

 

I needed a 1000 tonne crane to lift a 40 ton packaged generator from the road at the side of a Docklands building and to place it in the centre of the roof 14 stories up.

 

I'm surprised ANY mobile crane would weigh that much!!

 

:giggles:

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21 hours ago, Graham Davis said:

You might.
A lot depends on the distance the crane is from where the boat is. Remember at school studying "Moments" in physics?
https://www.bbc.co.uk/bitesize/guides/ztjpb82/revision/1

I remember a lesson on electromagnetism where my physics teacher (who I saw again last year) was talking about couples having their impulsive moments in fields. Cue some sniggering, which he expected.

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