How long is a piece of string?

[Twister_Ken]

I know the question comes into the piece of string category, but...

The Med marina where I currently have my itsy-bitsy sailing yacht (5 tons dry) is considering developing the hard-standing and equipping with a 100 ton capacity travel hoist.

So, roughly how big would a 100 ton motoryacht be in length terms? I'll take feet or metres, not fussy!

Thanks in advance.

 

[Firefly625]

quite long.

 

[Andrew M]

Yeah it'll be plenty long enough for most folks ! To give some idea of scale, I'd day a 60 footer would be roughly around the 30 tonnes mark.

 

[Cymrogwyllt]

http://news.bbc.co.uk/1/hi/sci/tech/8363934.stm

 

[BruceK]

Google being a friend shows this to be one of if not the longest 100 ton vessel:

Spirit of Yorktown
Gross Tonnnage: 97
Length (ft.): 257
Beam (ft.): 43
Passengers: 138

So I guess anything under that

 

[BruceK]

I still am struggling with that being only 100 ton though.

 

[l'escargot]

Gross tonnage isn't the weight of the ship.

 

[jfm]

Tonnage is volume not weight. A 100 tonne (weight) boat would be around 90-100 foot if a mobo. My 78 footer is about 58 tonnes for example.

 

[BruceK]

Gross tonnage isn't the weight of the ship.

Google is not my friend :disgust: Ah well, I'm still pottering around in 7 tons and still have a lot of growing up to do before I reach those weights :encouragement:

 

[thecommander]

When you own a boat that weight you soon realise your hobby has gotten out of control.

 

[Pinnacle]

In rag n stick speak, an Oyster 885 has a displacement of 71.5 metric tons. So that would fit nicely on a 100T hoist.

 

[Bandit]

Its not so simple.

You often run out of width, height under the crossbeam or the ability to spread the vessels weight equally between the front set of strops and the rear set.

With a narrow low steel boat you will probably max out near to max weight ( not GRT or net tonnage) providing the vessels shape allows you rig the front set and rear set of strops optimally, problems are stabilisers, exhausts, shafts and wing engines etc a 100 ton machine would probably have three strops per pulley block so you need about 6 foot clear length for each set without appendages in the way.

Large sailing yachts the fore stay and back stay may need releasing as they conflict with the cross beam (at the top of the hoist) also old style yachts with a keel shape like the old J class Vesheeda where you pick up with the forward strops on the keel at an angle of say 30 to 40 degrees off the horizontal are difficult to lift.

Modern fast motor boats are quite voluminous for their weight and on a standard width hoist you will often run out of beam before you hit the max weight capacity of the hoist.

Also motorboats with long saloons , the wheelhouse may conflict with the crossbeam.

Sailing Catamarans are a pain in the ass, often a 38ft or 40 ft cat weighing about 12 tons is too wide for a 75 ton capacity hoist.

A 100 ton hoist assuming not a super high or wide machine will probably lift a modern planning motorboat of say 120 ft and about 80 tons but probably a modern sailing yacht of say about 80ft, but a catamaran of no more than 45 to 50ft.

The other problem is large hoists cant lift very small boats a 75 ton machine wont lift smaller than a 20ft boat.