How to measure mast height ?

[Colvic Watson]

[ QUOTE ]
Measure the mainsail luff then add a bit for the distance between the foot of the sail and the mast foot.

[/ QUOTE ]
That sort of advice is typical of this forum sometimes. A guy comes along with a perfectly simple question and you take the micky with a ridiculous and over complicated suggestion like "measure the mainsail luff". Anyone with any experience knows that Fireball's seagull and air rifle system is the tried and tested way of doing the job.

 

[StugeronSteve]

[ QUOTE ]
Anyone with any experience knows that Fireball's seagull and air rifle system is the tried and tested way of doing the job.

[/ QUOTE ] Bollox it is!!! The impact's gonna knock the bird sideways off its perch for a start, so it's gonna be far to complicated to calculate the true fall time. About as daft as growing a tree at the masthead. Starling shite is the way, I'm telling you.

 

[moodycruiser]

Find a bridge over a river where you know that at that state of the tide the clearance is 10ft. Get a really good run at it (ramming speed) and continue under the bridge. When you come out of the other side, simply measure the bit of the mast that got chopped off, add it to (10ft - waterline to mast step height) , and hey presto - mast total height /forums/images/graemlins/wink.gif

 

[Colvic Watson]

And what if he damages his radar scanner in the process?

 

[fireball]

Yer - but www.fallingbirdcalc.co.uk allows for the shot impact effect - do you have similar calcs available for how long the bird takes to do its biz?

You do have to input the angle of shot though - if your standing underneath and shoot the bird will actually rise up first - so you'll get an inaccurate measurement - better to do 3 or 4 and draw a normal distribution curve ...

Oh - and if you moored round our way, yes you'd want to measure your mast on a regular basis .... /forums/images/graemlins/tongue.gif

 

[StugeronSteve]

No probs, he'll only need the radar if it's foggy, and then only to find the bridge. It's the poor starlings sitting at the top when it goes whack that worry me.

 

[StugeronSteve]

[ QUOTE ]
Oh - and if you moored round our way, yes you'd want to measure your mast on a regular basis ....

[/ QUOTE ] Well why not moor mast up like the rest of us then?

 

[fireball]

Why worry about the starling? Its the occupant behind the open window of the car that is going over the bridge as the starling is catapulted through that you need to be concerned about - they must be suitably aware of the process in order to react quickly in throwing the starling back out so it can land on the deck - otherwise it plays havoc with your timing ....

 

[Colvic Watson]

Which is why shooting the blighters is far more humane. No terrifying crash, no sudden catapulting into a fast moving car, no prospect of being hurled by said car driver out of the window. Just a swift clean death. And the guys radar stays intact. Eveyone wins that way.

 

[Gunfleet]

How about measure the luff of your mains'l then add the length from the foot to the deck?

 

[fireball]

That rather implies that it is the whole story - what if you don't get it all up? The main - to the top of the mast that is ... so - how many inches do you add?
If you want to get technical about it ... it would be easier to turn your backstay into a transmitting antenna and tune the set to give you the best transmission, then you can work out the length of the backstay as a calculation from the wavelength your transmitting on, then do your trig to work out the length of the mast ...

(of course - you could have halved the seagull population by this point!)

 

[Guest]

I still like the shadow method ....

Stand stick alongside mast with shadow cast on level deck. You know length of stick, you measure length of shadow ... measure length of mast shadow and you have direct relationship for calculation .....

Actually its a good way to get the length of stick as well - if you already know the mast height ...

Alternatively you could bounce a laser of the radar reflector and measure that ....

Alternatively get a friendly architect to bring along his IR / Ulktrasonic measuring device and align it so as to give mast height ....

Me I know the mast sticks about 3ft out from back of boat when laid along deck ... so that gives me 28ft..... good enough for me, for sail size - its the tape maesure attached to halyard job.

/forums/images/graemlins/tongue.gif

 

[Gunfleet]

well if you want to nit pick

I can answer the question AS IT IS SET easily. Send someone else up there.

 

[fireball]

Re: well if you want to nit pick

yup - then use the leaf method as described above ....
I suggest you don't try and modify the starling method though /forums/images/graemlins/crazy.gif

 

[Gunfleet]

Re: well if you want to nit pick

My Jack Russell hates starlings and grey squirrels. Maybe there's a method involving a dog, a starling, a squirrel and a prize. A minty chew will usually do.

 

[Colvic Watson]

Re: well if you want to nit pick

Why not combine all three. Drop the dog, squirrel and bird from the top of the mast. Won't help measure the mast but it'll be fun seeing which one lands first. Then eat the minty chew.

 

[StugeronSteve]

Re: well if you want to nit pick

Oh, and whilst you're going up there take the end of this tape measure with you.

 

[fireball]

Re: well if you want to nit pick

What ? Whilst carrying the dog and the nuts?

 

[StugeronSteve]

Re: well if you want to nit pick

I'd have thought the dog was capable of carrying his own nuts!

 

[fireball]

Re: well if you want to nit pick

It depends on the squirrel too ...