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470 Layout

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
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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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
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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Hi LaLi (and others), I am only just now getting back to try and continue work with my old 470. I have made some glass repairs and I have more to do.

I purchased some spinnaker bags and am looking for some replacement hiking straps. Does anyone have any suggestions for where to source out a set of straps? I'd like a set for the skipper and crew positions.
 
...also, I'm thinking of making a pair of lexan "doors" for the transom openings. I have some nice, thick (1/2") lexan pieces kicking around the shop. I'd like to stretch load them with some lengths of bungee cord.
 

LaLi

Well-Known Member
Does anyone have any suggestions for where to source out a set of straps? I'd like a set for the skipper and crew positions.
There are plenty of hiking straps on the market, but they're not necessarily a good fit for your boat or worth their price. I could link to Zhik or Mackay but I feel that would be somewhat beside the point. Are you going to keep the buckles on the floor stringers in front of the traveller? It might be then smartest to get some generic "seat belt" -type strap, and sew loops at the aft end for rope attachment. (The forward ends of today's straps are meant to be attached directly to the traveller track.)

One thing that needs to be said here: NO CREW STRAPS. All they do is get in the way of the crew. If you can't/won't fully use the trapeze, at least you can "hike" from the handles. I've had many complete novices do and enjoy that :D

Those straps that in the pictures are rigged for the crew look ok, so you could actually recycle them for the skipper's position?

I have some nice, thick (1/2") lexan pieces kicking around the shop.
Good material (polycarbonate), but more than twice the thickness that you really need. The flaps are just meant to keep the water out, after all :rolleyes:

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My Harken spinnaker bag purchase fell through. They no longer stock them. Arg! Will a set of 420 bags do the trick? They look the same, other than the 420 badge.
 

LaLi

Well-Known Member
Will a set of 420 bags do the trick? They look the same, other than the 420 badge.
They are probably very close to identical. (I don't even see a badge.)
They also look very, well... square, so they're not a perfect fit for any given hull. Attaching them so that they work nicely will take some time and effort. But more on that later :rolleyes:

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TakK

New Member
Hi Michael

I've been following your project as I've also got an old 470 from the 1970s that needs its rigging overhauled.

For replacing your toestraps, webbing is cheap and good enough. I guess you might be able to find something similar where you live?

For spinnaker bags, I've asked if my mother might be interested in making a halyard bag for me from my old tent. Maybe you could try the same trick and customise it for your boat if you know someone who's handy with the sewing machine?
 
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