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New mast building #280056
07/27/15 05:26 AM
07/27/15 05:26 AM
Joined: Aug 2011
Posts: 182
Grafton, NSW
Greg/Debra Offline OP
member
Greg/Debra  Offline OP
member

Joined: Aug 2011
Posts: 182
Grafton, NSW
Hi Mossies,

Over the last few months I have been slowly working on building a new mast. I have never built a mast before so this has been very much a learning experience. Matt has given me a lot of help and advice for which I am grateful (thanks Matt).

Now I have come to the curly question of how far to put the diamond T-bolts below the hound. Obviously I want the diamonds as high as possible without hitting the shrouds when the mast rotates.

The first thing I did was look at the three old masts we have; their dimensions vary from 230mm to 350mm.

Then I got to thinking about what factors would affect the shrouds hitting the diamonds, and this is what I have come up with...

If the hound is such that the shackle has free clearance from the mast, and if the shackle pin is smaller than the hole in the hound so it is free to move, then when the mast rotates the leeward shroud will won't be affected much.

However if the shrouds are closely fixed to the hound then when the mast rotates the leeward shroud will get wound around the mast (like a rope around a windlass). And that will effectively lower the position of the top end of the leeward shroud, and cause it to come closer to the diamond.

I am sure there are a few old crusty mast builders out there, so if anyone has followed me this far, could you please tell me if you think I am on the right track?

Thanks,
Greg.


1140 Gadfly
1434 J.I.B.E.
1727 Atreus
-- Have You Seen This? --
Re: New mast building [Re: Greg/Debra] #280114
08/03/15 04:13 AM
08/03/15 04:13 AM
Joined: Apr 2013
Posts: 858
Victoria Australia
Pirate Offline
old hand
Pirate  Offline
old hand

Joined: Apr 2013
Posts: 858
Victoria Australia
About to start putting Karps new mast together....

pic and measurements would be awesome everyone

grin


Yar, & this ere post be done without a sin'le drop o' rum passin' me lips

Kingy
started with Impara Cadet #3 / Mosquito #245
& now Mosquitos #1182 & #1740

Re: New mast building [Re: Greg/Debra] #280115
08/03/15 04:42 AM
08/03/15 04:42 AM
Joined: Aug 2011
Posts: 182
Grafton, NSW
Greg/Debra Offline OP
member
Greg/Debra  Offline OP
member

Joined: Aug 2011
Posts: 182
Grafton, NSW
Hi Kingy,

Our new mast is almost finished and hopefully we will get to try it out next weekend. I wouldn't be surprised if we find something we would change, once we get on the water, but we will have to wait and see.

Much of what I did was on advice from Matt. I can pass on the measurements I used, but in the end it is your call. Also some things depend on what fittings you are using.

I am prepared to offer any help I can. Good luck!


1140 Gadfly
1434 J.I.B.E.
1727 Atreus
Re: New mast building [Re: Greg/Debra] #280192
08/10/15 05:06 AM
08/10/15 05:06 AM
Joined: Aug 2011
Posts: 182
Grafton, NSW
Greg/Debra Offline OP
member
Greg/Debra  Offline OP
member

Joined: Aug 2011
Posts: 182
Grafton, NSW
We went up to Grafton today and put our new mast up. Anyone who has built a new mast will know that there are few things to fiddle around with, so it takes a while, but generally most things went well for us today. We got some lovely mast bend happening and there are a couple of photos below.

However... Clarence River Sailing Club suffers from vandalism, as a lot of places do and this afternoon a youth got up on the roof of the Clubhouse, and threw some rocks at us. The first one he threw was as big as a tennis ball and could have possibly killed one of us, had it hit us in the head. The second one was much smaller, sharp and went straight through our new mainsail. Photo attached.

That put a bit of a downer on our afternoon, but otherwise we are pretty pleased with the first try of the new mast.

[Linked Image]

http://s24.postimg.org/trftl40k5/Mast_bend_1.jpg

[Linked Image]

http://s1.postimg.org/5n5da1alr/Mast_bend_2.jpg

[Linked Image]

http://s15.postimg.org/d9oz2t1gb/Stone_hole.jpg

Last edited by Greg/Debra; 08/10/15 06:17 AM.

1140 Gadfly
1434 J.I.B.E.
1727 Atreus

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