mast rake measurement

beaker

beaker

hi
I have read all the posts.....here is my question where does the measuring tape come down to? What is a tangent? I have 12' 1" at my transom top.

Any one have a book that explains this?
 
beaker said:
I have read all the posts.....here is my question where does the measuring tape come down to? What is a tangent? I have 12' 1" at my transom top.

Any one have a book that explains this?
Click to expand...
One measure from the rear side at the top of the lower (Standard) mast segment (that is in the masthole in that position that it is at the rear wall of the masttube) direct to the edge of the deck at the transom at the center line of the deck. The mast rake of my Laser (built in Dec 2000) is about 4025 milli-meter.
Ciao
LooserLu
 
This is copied from Ainslie's book (The Laser Campaign Manual):

(p. 10) Put the bottom mast in the boat and 'rake' it back. Hook the end of a tape measure to the top/back of the mast and measure to the middle of the round of the transom. 148 cm is raked back, 152 cm is raked forward. If in doubt, forward is better because it's quick downwind and you get good leech tension upwind.

Clearly, this is quite different :confused: from what LooserLu wrote....

It appears that the Ainslie book wasn't proofread accurately. His numbers make more sense if 'cm' is replaced by 'inch'.

148" equals 376 cm
152" = 386 cm

But this is still significantly different from LooserLu's measurement. If it wasn't so cold, I would go out and measure the rake on my own boat. Any other volunteers?
 
I measured about 80 local Lasers in the late eighties. The range was 148 inches to 154 inches.


The Vanguard boats I measured were all within about a quarter inch. It is dark and cold or I would make up some other excuse for not bothering to check. My recollection is 150 1/2 or 151 1/2 is the builder's target.

When around year 2000, they all seemed the same I quit worrying about it.

What's a tangent????? We buy books and pay teachers and send you to school and we get that result??
 
It all depends on the classes you enroll in. The tangent as I know is the angle gotten when dividing opposite from adjacent. I am just trying to see if I am doing it correctly because my numbers do not match the range.

Mine measures 144 inches from back of top section to middle of stern round rail.

Way off of others.

I spun my mast 1/4 turns to check if measurement changed and it did not. No wonder why my I feel like I have a ton of helm. I am fighting the boat.

So...... Shim it or epoxy up a repair?
 
Has your mast step been repaired before? If you are 4" off from the top of the bottom section the base of your step should only be off an inch or so. If you shim the back of your mast step you'll see about how far you need to move the base of the step, (where it connects to the hull). You will need to fix the problem where the base of your step connects to the hull inside the boat.
 
nope no repair done. I have a sheet of delrin I am going to wrap the mast with to see how it stands up. probably will do some Epoxy magic on the step to pull the front of the mast back.
 
update I bought an inspection port and put it between Cunningham cleat and fairlead. Once a light was put behind the step I found three vertical cracks and more around the base. The base was forward about half an inch and to the left about the same. I could not move it so the repair was made to fix the cracks.

So I will attempt to shim it for frostbiting and the wife gave the ok to buy a newer one for race season.
 
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