mast climbing

[Larry DeMers]

Neil,

Hee, oh I have done the same damn thing. I am a rather larger than necessary person, and after helping get a friend to his mast truck to rereeve his halyards, I stepped off the boat. Oh man, did he go for a ride! The wind seemed to keep him going too..back and forth, eyes glazing over, that funny feeling in the back of the throat..and that was me! He was fine..legs and arms wrapped around the mast.

I guess climbing the mast is something that I hate (due to height). I can get to the spreaders easily, but convincing myself to climb past them is a struggle.

Larry

You got the physics right, I think. The practical problem in actually going aloft is knowing that the rig will support the climber, allowing for the wake from some passing $&*#$@, and remembering that you don't have to be over 90 degrees before the water forgets to stay on the outside.

That said, there are practical solutions, too. If you start going aloft, you only change the weight distribution a little at a time... if you're four feet up and the boat's over 15 degrees, stop climbing. If you get to the spreaders and you're still in trim, keep going.

I watched a fellow on a Catalina 25 go up so where he was just over the spreaders. All was fine until his soon to be ex-gilrfiend stepped from the dock to the deck. He swung in a fair arc, but didn't come near a knockdown. <g>


Regards, Neil
s/v LIQUIDITY
Cape Dory 28 #167

demers@sgi.com

[Warren Kaplan]

I've enjoyed all this theoretical stuff. God, I haven't done any of that since I was still using a slide rule (which my kids have never even heard of) back in college. On a more practical nature....I got a new Furlex furler mid season. The guy from Doyle sailmakers went up the mast, to the masthead on my CD27. He was about 180 pounds. He was up there quite a while installing a new jibstay with the new furling gear and new genny. The boat never waivered. I yelled encouragement to him from the dock the whole time. I wasn't scared a bit!



Setsail728@aol.com

[Ken Coit]

Great story!

Any math wizzards out there that want to take on the relationship between capsize ratio and additional weight on the mast in a stiff breeze?

Capsize ratio for a CD-30 seems to be 1.67; for a CD-36 it seems to be 1.73.

Check out this and other interesting thoughts at:

http://www.image-ination.com/sailcalc.html#bbb

BTW, those loglogdecitrig 'rules are again worth almost as much as we paid for them.

Ken

I've enjoyed all this theoretical stuff. God, I haven't done any of that since I was still using a slide rule (which my kids have never even heard of) back in college. On a more practical nature....I got a new Furlex furler mid season. The guy from Doyle sailmakers went up the mast, to the masthead on my CD27. He was about 180 pounds. He was up there quite a while installing a new jibstay with the new furling gear and new genny. The boat never waivered. I yelled encouragement to him from the dock the whole time. I wasn't scared a bit!

parfait@nc.rr.com

[M. R. Bober]

Pickett or K-E? Remember yellow or white? The batteries never failed and 3 significanr digits are all you really need (actually one will do if someone throws you a big wake while you're up the mast). Thanks for the trip down Memory Lane.
Mitchell Bober
RESPITE
CD330

[Dan H]

Thank you all for the great responses. The math lessons were fun, but the real numbers only make it all the more a dubious undertaking. You see I weigh about 155 lbs (add about 6 to 8lbs for clothing). The mast on a CD25 is about 30 ft.above the fulcrum (formerly known as water)line. The draft is 3ft. and the ballast is 1700. Plug in these numbers and you get me on top of the mast with a force of about 4950 lbs. and the boat at 5100 lbs. Now through in the fact that I am on a can and not at a dock. Toss in a little Murhpy's law to ensure a power boat whizzes by, and I become a perpetual motion machine swinging a 178 degree arc for eternity.

Good question - I look forward to some responses on that one! Especially since I weigh 230lbs.

djhhan@aol.com

[Larry DeMers]

Well, you would probably make the evening news a bit more interesting than who is trying to steal the presidency this hour..!
Hey, maybe you could talk the fuel dock into letting you tie up for an hours time while you went up the stick.

I agree with you..your situation is too close to the neutral point to be safe. If you could tie the mast off on both sides while at a dock, then it might be a thing to do..otherwise, better lower the mast or use the mast crane to lift you up there.

I can see you now..swinging waayyy over to port, slowly coming back, going right through upright, and swinging way over to stbd. Quite the ride!

Cheers!

Larry DeMers
s/v DeLaMer
Cape Dory 30 ~~~Sitting in the cradle waiting for the white stuff
to disappear! -on Lake Superior~~~

Thank you all for the great responses. The math lessons were fun, but the real numbers only make it all the more a dubious undertaking. You see I weigh about 155 lbs (add about 6 to 8lbs for clothing). The mast on a CD25 is about 30 ft.above the fulcrum (formerly known as water)line. The draft is 3ft. and the ballast is 1700. Plug in these numbers and you get me on top of the mast with a force of about 4950 lbs. and the boat at 5100 lbs. Now through in the fact that I am on a can and not at a dock. Toss in a little Murhpy's law to ensure a power boat whizzes by, and I become a perpetual motion machine swinging a 178 degree arc for eternity.

Good question - I look forward to some responses on that one! Especially since I weigh 230lbs.

demers@sgi.com

[Ken Coit]

Mitchell,

K&E log log duplex decitrig. Now that I have given, the brain cells a warm up period, I remember it all. White, of course. With name engraved, of course. Mine must be a 1957 version. Aren't spreadsheets wonderful? Ever used MathLab?

We had a thermodynamics prof. that used a cylindrical rule which could knock out 5 places. He delighted in giving us the full five places on our homework papers, but always settled for answers that were close. He must have had a lot of time on his hands. The good old days!

As you say, those last two digits are irrelevant when considering dipping into the cold blue from the mast head. 10% is plenty close enough.

Ken

Pickett or K-E? Remember yellow or white? The batteries never failed and 3 significanr digits are all you really need (actually one will do if someone throws you a big wake while you're up the mast). Thanks for the trip down Memory Lane.
Mitchell Bober
RESPITE
CD330

parfait@nc.rr.com

[Marino Curati]

This summer before a race, there was no wind. As we all bobbed around for the seemingly endless time until the committee pulled the plug, we noticed a boat (express 32 or something similar) with a bunch of kids on it. What they were doing was getting up a good head of steam and then throwing the helm hard over with most of the kids on the outside of the turn which caused the boat to lay way over. There would be one kid perched on the stern rail holding a halyard in one hand and the backstay in the other. When the boat was about halfway into the turn, he would swing tarzan style through the rest of the turn - which made the boat now heel really far over. It looked like incredible fun; they would be flung some twenty feet when the let go before getting to the bow. One kid even cleared the bow and went full circle.

I can't imagine that being very safe or good for the rig, but when reading of weight ratios and righting moments it reminded me of watching some good old gravity induced fun.

I've been aloft on numerous boat over the years and never really considered outweighing it. I think its more of a feeling you get when you're half way up. I obviously would not go up on my Typhoon, but never think twice about going up on the S2 7.9 I race on. Its a centerboard boat and according to the numbers, it could capsize, but it has never felt unstable to me either at the dock or in open water during a race. Anyway, this is one of the more interesting topics.

Marino Curati
Ty #74 Snug
Cleveland



mcurati@vision-design-inc.com

[John D]

>>I know the force of the wind on the sails increases geometrically (?) or in twice the wind there is four times the pressure per square foot of sail.<<

True, except that as the boat heels, the effect of the wind on the sails decreases. With the boat over 90 degrees, the sails have no effect at all.

>>I need to hook up with someone here to help me get over that falling over" feeling that I'm sure you all had to get over at one time.<<

It's because you forget that the keel is down there, keeping the boat upright. Experience makes it look and feel like you are capsizing, but you're not.

If you don't have a clinometer on the boat, get one, so you know what the angle of heel is. Then, button up the cabin, close the hatch, ports, etc. ('cause in your head you know the boat's gonna fill up and sink!), and go out on a breezy day. See how far you can get the boat to heel... try to get the rail in the water. It's not easy! If you start to panic, just let go of the tiller. You'll head up and the boat will stop. After a while, you figure out that the tilt is both normal and something you control.


Regards, Neil
s/v LIQUIDITY
Cape Dory 28 #167

Thanks Neil - I just need to hook up with someone more experienced to do it once or twice and I'll be fine. Can't be that tough in Puget Sound right?

John
S/V Mariah
Cape Dory Intrepid #34



john_dupras@hotmail.com

[Olli Wendelin]

Am I the only one that carries a circular slide rule on the boat? We used these in the navy for figuring CPA (closest point of approach), torpedo firing solutions (probably not applicable here), and any time multiplication or division was needed. No batteries required, and you can even hang it from your neck.

Olli Wendelin
BLUE MOON
Charleston, SC



wendelin@spawar.navy.mil

[Fred Adame]

Air Force navigators (and USN aviators) have used circular slide rules for a long time; they were part of an E6B "computer" which could figure a course corrected for drift.

Circular slide rules are great on a boat: faster then an electronic calculator, no batteries, and can be manipulated with one hand. Only problem is getting used to the logarithemic scale.

Fred
(old USAF "nav" and F-111 bombardier)



fnav@earthlink.net

[David Brownlee]

Some specifics:

When I was younger, a friend I went to the masthead of an Irwin 27 several times while at sea in moderate consdtions. We both weighed about 150 pounds at the time.

More recently, I went to the masthead of our CD 25 (outboard version) several times while at the dock. Weight about 165. My wife was on deck. I felt no instablity.

David Brownlee
CD27 #181 (for sale!)
CD31 #1
both called WINDRUSH




dbrownle@saws.upenn.edu

[Ken Coit]

And us old auto rallyists probably have a circular rule in our storage boxes too. I can't remember the manufacturer, but they were about 8 inches in diameter, so the scale was more than twice the length of those 10 inch K&E (Keuffel and Esser) and Pickett rules. There is one around here somewhere, in its leather case.

Ken
old driver for Arizona Sports Car Association Rally Champion
circa 1963



parfait@nc.rr.com