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S&S Swan General - Mark on the mast of a 411 and position
07 June 2018 - 18:52
#1
Join Date: 07 October 2014
Posts: 74

Mark on the mast of a 411 and position

Hello I am having another question:

I often see the mark on the mast and think, that is schowing the position of the hight.

but it is not flush with some think.

Is the mast ny be shorter?

Then there is the slider for the mast.

Is any body using this for doing trim?

Since i can not realy move the position, looks like it is in the middle. is that fine?

Looking forward to recive your knowledge of all that great stuff they did on our s&s swans.

Stefan 411 / 02

mark

mast step

10 June 2018 - 07:47
#2
Join Date: 02 January 2008
Posts: 1547

Dear Stefan

The mark is the "Lower I" used during the IOR rule day days, shows the calculated deck height without coachroof.
Recommended mast rake is 1 degree, this is 17.5 mm/metre. The distance from mast step to deck collar is about 2 metres, suggesting a rake of 35 mm below deck.
Kind regards
Lars

11 June 2018 - 01:54
#3
Join Date: 07 October 2014
Posts: 74

Dear Lars,

thank you for clearing me up.

Now i will not have some ??? when i see the mark on the mast :-)

So the "rake" i can measure when the boat is in level and i put some line in the back of the mast under the seiling with a heavy weight on the bottom close to the mast step and there should be a clearence of 35mm - is that right?

what´s about the mast bend, is that going also in that 1 degree measurement?

Kind regards, Stefan

11 June 2018 - 06:29
#4
Join Date: 05 August 2010
Posts: 162

Dear Stefan,

here are two pictures regarding your mast shoe arrangement, taken some five years ago when we did a major repair.

The base plate (what I call "shoe") is a stainless steel construction with a rim welded to a plate. The mast is placed inside the rim. With the help of the big bolt, you can move the complete assembly fore-and-aft, provided you have loosened the four bolts securing the shoe in place. That is how you can trim the rake.

However, the shoe is stainless steel and the mast is aluminium. You will have to make absolutely sure that water can drain out of the rim, and I suggest flushing the mast inside with fresh water every once in a while. Just put a hose where the halyard comes out, and water will run through the mast into the bilge. When the boat is on the dry and you have a functional bilge plug, there is no problem at all; when on the water you will have to pump out the bilge afterwards. Sounds like trouble, but if you take a look at the second picture showing the foot of our mast before the repair, you will understand. Check for corrosion at the lower end of the mast, as it may become really dangerous. The mast foot takes a lot of compression force when you are sailing.

Best regards,
Martin (Age of Swan, 48/039)

 

 

 

Base plate assembly

Mast foot corrosion

11 June 2018 - 07:36
#5
Join Date: 02 January 2008
Posts: 1547

Dear Stefan

You can measure the rake below deck as you described.
Assuming your headstay has the correct length for one degree rake, the mast will be straight when set up with this rake, and the backstay is slack. 
If you tension the backstay, the mast will bend aft at the top. Suggest you start with this basic setting - one degree rake and bend induced by the backstay.
The amount of bend can be adjusted by moving the mast lower end, moving it aft increases bend.
The white powder visible around the mast shoe is aluminium oxide, a product of mast corrosion, and I very much agree with Martin that you must make sure that water is not standing inside the mast. Big drain holes also improve bilge ventilation.
Kind regards
Lars

12 June 2018 - 00:08
#6
Join Date: 07 October 2014
Posts: 74

hello martin, hello lars,

thanks for that good pictures and good explaining. saw alredy somebody fixing the corosion problem, by cuting the bad stuff away and doing a mast feet with some epoxy with high density filler. so there will be also an electrical barrier.

think my mast looks not that bad, but earlyer or later i have to do the same thing. yes i found the holes for drain the water. in my case it is at the moment only rain water. i made kind of box to collect the water under the step and than it runs in a tube down to the bilge pump. because the section in between is quiete bumpy and for normal the water is standing there. want to install a vent in the bilge section of the forward cabin to blow air trough the whole bilge to blowthe moist out.

i measured and it will may be still fine after installing the new rigging next season. i will put the project about the maststep on another day.

the previous owner that was setting up the rigging and having the boat over 10 years, is having a sail and rigging company here - think he did it in a propper way.

will try to make the mast stepp movable again.

for you in europe the season must be on - fair winds

 

so helpfull to have this forum - thanks

 

Stefan

 

 

 

mast curve

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