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S&S Swan Maintenance - Model 431 Mast Step Removal
18 November 2014 - 13:55
#1
Join Date: 17 November 2009
Posts: 38

Model 431 Mast Step Removal

I am beginning the process of replacing the mast step in Andiamo (431/25).

The forum's history with this topic has answered all but one of my questions (thank you S&S Swan association for your very existence).

For a 431, can the mast step be removed without cutting it into pieces (and without enlarging the main hatch above the engine)?

"Its often useful to know where you will be.. before you get there."

Thank you, Kendall


18 November 2014 - 20:19
#2
Join Date: 02 January 2008
Posts: 1547

Dear Kendall
Suggest you measure the length of the mast step transverse steel floors, and check if they pass through the hatch.
Kind regards
Lars

24 November 2014 - 21:29
#3
Join Date: 17 November 2009
Posts: 38

Thank you Lars for answering.

It seems it will likely fit through the hatch.

The metal fabricator at the yard (she is in) wonders if the rust observed (and associated loss of material thickness) warrants replacement of the step. As such, the current plan is to expose and thoroughly clean the step when the mast is removed next week. Then measure thicknesses and compare with as built specs from Nautor.

My question is: Is there an accepted rule of thumb.. suggesting how much loss in thickness in the metal plates which make up the step is "permissable"? Certainly a 1% loss might be deemed structurally sufficient. What about 10%? 20%?

Of course the location of the rust and associated loss is location dependent. A good steel brushing could make the upper half look new with no loss in thickness (I suspect).

So if there is a rule of thumb on assessing the thickness loss (and we are less than that), then.. we will clean, install thick washers and prepare the surface to resist further rusting).

Does the experience gained in the association here suggest this approach is reasonable or a waste of time? Anyone gone this route and been happy/sad with the approach?

Much appreciated.

Kendall



Also I wonder if the Nautor supplied blueprints are "as built"?

25 November 2014 - 10:35
#4
Join Date: 02 January 2008
Posts: 1547

Dear Kendall
There is a rule of thumb on the Forum, see post dated 15 June 2010 in the Maintenance section.
Referring to your question about the blueprints it is assumed this refers to the keels, which are slightly different for early and later hulls. For hulls from 016 upwards there is a GRP wedge between the hull and the lead keel forward. The wedge is 100 mm high at the forward end.
Kind regards
Lars

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