470 Layout

Thread starter #73
Measure the distance from the transom to the aft edge of the mast. The spar should stand at 90° to the mast gate (just for this measurement!), and you should include the mainsail track, as if it came all the way down where it's actually cut off now below the boom. The reading should be about 3095 millimetres. Chances are that the mast foot is farther back (smaller number) than that now. This is also part of the basic tuning; your sails may be some very old cut which may have used settings very different from the modern ones, but I still think that is the best figure to use as a starting point.
Hello, I'm finally getting back to this rigging project after having been torn away with other, less interesting work.

I'm not sure about this measurement that you mention, here. I get the measurement from the transom to the aft part of the mast (3095mm), but what does the main sail track have to do with the measurement? Also, am I sticking a nice, big carpenter's square on the deck to check that the mast is perpendicular?

I got my new Ronstan I beam from APS and took the old bent one out (I can't imagine how that got bent!). I now have to cut it to length and drill some new holes in the correct spots but the beam shape does fit, thankfully. A pain in the rear end to get the hardware off!

I'm still waiting for a few hardware pieces to finally get my boom vang rigged up but that should be done this week.

I will have to switch to fixing some running rigging problems on our racing boat (a flying scot) this weekend but I'm sure that I'll have a bunch more questions in the coming days regarding the 470.
 

LaLi

Well-Known Member
#74
I get the measurement from the transom to the aft part of the mast (3095mm), but what does the main sail track have to do with the measurement?
Your mast is an Elvström, which has the sail track cut away below the boom. The measurement is done as if the track continued all the way down (it's a class rule), so you need to subtract the track depth from the measured transom-to-mast distance.

am I sticking a nice, big carpenter's square on the deck to check that the mast is perpendicular?
If you absolutely want to :D But it's not really that accurate - the purpose of the measurement is to ensure that you're not totally off the scale. The 3095 mm is actually a number that I remember using for a former club boat years ago. The current North tuning guides give similar values; 3100 would probably be easier to remember. The class rule maximum is 3115.

Chances are that you want to move the mast foot forward on the step, but we don't know that yet.

I got my new Ronstan I beam from APS and took the old bent one out (I can't imagine how that got bent!). I now have to cut it to length and drill some new holes in the correct spots but the beam shape does fit, thankfully.
Cool! Have you thought about keeping the vintage single-car system vs. changing to a bridle? (The track has to be there even if there's nothing "travelling" on it.)

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Thread starter #75
Your mast is an Elvström, which has the sail track cut away below the boom. The measurement is done as if the track continued all the way down (it's a class rule), so you need to subtract the track depth from the measured transom-to-mast distance.
OK, I see the sail track section extending below the boom below the boom.
Sail Track below the boom.jpg

...and I have this measurement (approximately 3060mm) from the transome to the aft edge of the mast, along the centerboard trunk.

Measurement from Transome.jpg
Measurement From Transome 2.jpg
...oops, that's really blurry.

So, am I subtracting the little bit of sail track below the boom from the measure ment I made (3060mm)? Am I getting this correct? If so, this is looking like my mast needs to move forward. The boom is pretty close to perpendicular withe the deck surface, as measured with a square.
 

LaLi

Well-Known Member
#76
You measure how much the sail track protrudes (horizontally) from the mast (some 20 mm, maybe), and subtract that from the 3060 mm. But your mast really appears to be :eek: illegally far back! The minimum is 3055.

The next thing to do: move the mast to the forwardmost hole in the step and measure again.

(This is actually interesting. It looks like the whole fitting is farther back than on later boats.)

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