magnum 8 moth query

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scorpion_1925
Posts: 41
Joined: Fri Aug 10, 2012 12:40 pm
Location: york

magnum 8 moth query

Post by scorpion_1925 » Sun Nov 17, 2013 11:02 pm

I was wondering if anyone could give me any tips or figures for rig settings, mast rake rig tension etc for different wind conditions

Having sailed my scorpion for years I have rig settings for every conceivable wind and wave condition which I find a very useful starting point
Scorpion 1925
International moth magnum 8

Ford Capri

bornagainmothie
Posts: 220
Joined: Mon Apr 23, 2012 1:28 pm

Re: magnum 8 moth query

Post by bornagainmothie » Mon Nov 18, 2013 1:28 pm

My advice is throw the books away, you will need all your concentration to sail the boat. There are no set measurements or sailmakers guides, its all done by the seat of the pants, usually soggy ones!

Most of the pointers you need were in this discussion from a few months ago:
viewtopic.php?f=4&t=4935

scorpion_1925
Posts: 41
Joined: Fri Aug 10, 2012 12:40 pm
Location: york

Re: magnum 8 moth query

Post by scorpion_1925 » Mon Nov 18, 2013 1:48 pm

Thank you, back to old school suck it and see
Scorpion 1925
International moth magnum 8

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bornagainmothie
Posts: 220
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Re: magnum 8 moth query

Post by bornagainmothie » Mon Nov 18, 2013 2:28 pm

It is really, there are so many different hull/rig/sail combinations that measurements are pointless.

Mast rake, as Jim suggested is get the tip of the mast somewhere over the daggerboard (with downhaul and kicker on) and rig tension, as Ian wrote, just enough to prevent the leeward shroud waving around upwind.

After that its down to how the boat feels and some basic theory, like rake back more in a blow. If you are stable enough to have time to pull strings, then watch the tell-tales and adjust accordingly with kicker and downhaul.

scorpion_1925
Posts: 41
Joined: Fri Aug 10, 2012 12:40 pm
Location: york

Re: magnum 8 moth query

Post by scorpion_1925 » Mon Nov 18, 2013 3:15 pm

It's the stable enough to see what's going on that's causing the problems I'm sailing on a very small and very shift pond
Scorpion 1925
International moth magnum 8

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bornagainmothie
Posts: 220
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Re: magnum 8 moth query

Post by bornagainmothie » Mon Nov 18, 2013 7:55 pm

I'm sailing on a very small and very shift pond
Welcome to Masochist corner, it doesn't get much more difficult than that, I should know!

...but I think its true to say you need to worry even less about fine tuning of rig measurements and more about keeping the wings out of the water.... easier said than done!

Are you having a particular problem with the boat in certain winds or are you just checking its set up correctly?
Do you have any photos?

scorpion_1925
Posts: 41
Joined: Fri Aug 10, 2012 12:40 pm
Location: york

Re: magnum 8 moth query

Post by scorpion_1925 » Mon Nov 18, 2013 9:54 pm

Yes keeping the wings out of the water very quickly became apparent as being key. My biggest problem that I can only solve with practice is tacking or more precisely carrying speed through tacks. I can tack and survive quite successfully but I mostly come out stationary.

Running is also a challenge, but again it's just practice I need.

Small pond sailing is certainly a challenge in it.

My main reason for asking was that I've got over the first hurdle, I can get it round a race course in most conditions, not always last and having got to this stage I was curious to see if the rig setup was even remotely near to correct
Scorpion 1925
International moth magnum 8

Ford Capri

bornagainmothie
Posts: 220
Joined: Mon Apr 23, 2012 1:28 pm

Re: magnum 8 moth query

Post by bornagainmothie » Tue Nov 19, 2013 2:15 am

You are doing well to get round the course at all in shifty conditions, so stick at it, with practice you will soon be working through the fleet.
Tacking without stalling is crucial for the pondsailor. Its easy enough to do in a Laser for example, but they have a nice soft sail that flops into place on the new windward side after the roll tack. We have the on/off switch that is a fully battened sail.
Flicking the battens over in light winds is a matter of timing and control. Timing, in that it needs to happen as you pull the boat upright from the roll tack. Control, because the sail takes shape on the new windward side just before upright and needs to be at the correct angle to the wind to re-fill and start to flow air again. It needs some precision with steering, a good wind awareness and confidence in your movement through the boat to achieve all that. Body weight has to be in the right place all the time, helping the hull turn the corner with very little rudder.
Usually it all goes well until the battens get stuck the wrong way, the boat stops dead and you sit there wobbling and thrashing at the boom to shock them over. Does that sound like your problem?
A deeply cambered sail will lock itself in shape and be difficult to flick over. Too much tension in the battens has the same effect. Ideally in light winds a flatter sail shape will flow better and be easier to get going from a stall. I use quite a stiff top batten to support the leech up top but softer ones lower down to keep flexibility. Virtually no tension on any of them.
Upwind, pull on the cunningham/downhaul to bend the mast and prevent the top leech from hooking to windward. A little bit of kicker to control the leech tension. Set like that I find, at the right moment in the tack, I can reach up and prod the bottom batten with one finger and the rest tumble over like dominoes, very satisfying!
If you can get the sail to tack reliably, a further help to speed out is to leave the boom out a little, come out of the tack on a close reach, build speed, then point back up to close hauled.

In heavy winds there is no problem flicking the battens, usually the trouble is getting stuck in irons unable to bear away. The trick here is to throw yourself onto the new windward wing and lean forwards, heeling the boat over to windward as the sail fills on the new tack. oh, and pump the mainsheet like crazy till it lifts you out of the water and you take off. A little bit of windward heel on the beats will help counteract any weather helm.

Running??? that really is brave! It has to be done on some courses but its usually safer and faster to broad reach and gybe. If it has to be a run, keep one eye on the burgee and don't ever go running by the lee. Careful easing of the kicker can increase speed in light to medium wind but pull it back on quickly when the rolling starts.

Hope that helps

Lyndon

scorpion_1925
Posts: 41
Joined: Fri Aug 10, 2012 12:40 pm
Location: york

Re: magnum 8 moth query

Post by scorpion_1925 » Tue Nov 19, 2013 8:09 am

Thanks Lyndon

I have been playing with batten tensions a bit but will have another look at them. They do sound key to my problems. Yes stuck in irons in strong winds has been an issue usually resulting in swimming dues a wind shift and gust hitting just as I'm sorting it.

Sounds like I'm getting it right just need more practice, I might see if I can take it somewhere bigger so I can go more than a minute in one direction before running into a bank or another boat
Scorpion 1925
International moth magnum 8

Ford Capri

simonmw
Posts: 49
Joined: Tue Sep 25, 2012 8:17 pm

Re: magnum 8 moth query

Post by simonmw » Tue Nov 19, 2013 8:24 am

I agree entirely with what Lyndon has said- also one thing I have found with mine is that although it seems to be faster in a straight line to add more mast rake when the breeze is stronger, it compounds the problem of getting stuck in irons (and inevitably falling over) on the tacks- so there is a fine line between adding more mast rake for windy conditions, and adding too much so it is counter productive. With less rake, the centre of effort moves forward helping the boat to bear away.

So- more rake when windy, but if you are really struggling getting stuck in irons, try reducing it back towards a more moderate wind setting. It's faster to be upright and moving than stuck in irons or swimming!
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