Originally Posted by Iain Mac
Good afternoon all - This is my first time and I hope you'll be gentle with me - I also hope I don't offend anyone! I own a 1939 12 ton Hilyard called Lady Corinne. She normally comes out @Birdham Pool in Chichester and they know just how to handle her. Unfortunately, due to developments at the marina they can no longer accommodate us and we are moving to the new shed in Chichester Marina. The people who would lift
the mast have asked for the weight and I have absolutely no idea. I wonder if anyone might be able to help me please.
The mast is 49' of Solid Douglas Fir in total (It's keel
stepped ) and goes from 7" diameter at the base to 4" at the masthead. All the standing rigging
is oversized @ 10mm stainless and consists of:
Forestay with Roto stay furler
Inner forestay with Roto stay furler
2 sets of solid Douglas fir spreaders
set around 3/4 of the way up
2 stays from the hounds on each side
I realise that this will be a bit of guesswork to say the least but would be very grateful for any sensible suggestions that you might be able to make
Simple weight of a column calc. I'm assuming a round, not square, mast.
Also assume mast is 7"diameter over whole length. It's not but we dont want calculate the weight of all fittings. I've rounded up after calculating to allow for all the rigging and mast mounted paraphenalia.
Douglas fir density = 530 kg/ m^3
Length = 49' assume 13m
Diameter = 7" assume 0.178m
Area of a circle=pi*(diameter/2)^2
Volume of a cylinder=Area of circle * Length
W=530×0.32=170kg or 375#
So assume max lift weight of 500# (227kg or 1/4 US ton)
I would then use a crane and rigging gear
rated for 10 x the calculated lift weight. 5 tonne crane with a pure vertical boom lift will be fine.
In reality any boatyard crane should be able to handle this weight. The biggest load may be cracking rhe mast free if its stuck. Lift height and boom reach and swing will also need to be calculated.
To be honest I dont know why the yard expects you to provide them with the mast weight. Is this their first lift?
I'd have the yard show me their calibration certs for the crane, lifting gear
and crane operator. If they can't and I don't like the look of their gear then they don't lift it.
Sounds like a nice boat. How about a pic...
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