Okay guys-

Several people have asked me for the "numbers" I got on my mast using the Goodall's mast bend test.

Here they are, my numbers first ("typical" range following):

Tip deflection-

Fore-aft: 48mm (35-45mm)

Sideways: 179mm (140-170mm)

Lower mast bend-

Fore-aft: 12mm (8-10mm)

Sideways: 47mm (38-48mm)

As you can see, all my numbers are above, or at the upper limit, of the "typical" range. Mine is a 1997 model w/ the sloop Superwing mast.

Here's the test, compliments of Goodall's -



MAST BEND TEST FOR TAIPAN 4.9 MASTS



For this test you will require 2 saw hawses, a G-clamp, a 20 kg weight and a tape measure.

Remove the diamond wires from the diamond arms.



TEST 1A: Tip Deflection - "Fore-aft"

 Position the mast sail track DOWN and clamp the mast base so that it does not move.

 Place a support under the hound position, 6000mm from the base so that the mast will pivot at this point.

 Place a 20kg weight at the tip and measure its deflection downwards.



TEST 1B: Tip Deflection - "Sideways"

 Same as for test 1A except lie the mast on it side.



Typical bend test figures for these tests are 35 - 45 mm for-aft, and 140 - 170 mm sideways.



TEST 2A: Lower mast bend - "Fore-aft"

 Position the mast sail track UP and clamp the mast base so that it does not move.

 Place a support under the hound position, 6000mm from the base so that the mast will pivot at this point.

 Place a 20 kg weight midway between these two supports and measure its deflection downwards.



TEST 2B: Lower mast bend - "Sideways"

 Same as for test 2A except lie the mast on it side.



Typical bend test figures for these tests are 8-10mm for-aft and 38-48mm sideways.



 Check the mast for fore aft straightness.

Note any permanent bend in the mast as this will effect the required luff curve in the sail.





When I get my new (old) "cat specialist mast" from Australia via Michael I will test it also- If others who test their masts could post their numbers we could arrive at our own "typical" numbers and get numbers for some other boats too--

Enjoy!



Kirt

Kirt,

Finally got around to measuring some masts.

I made up cradles to support the mast in each plain out of 4x2 oregon cut to the mast profile. As a weight I used 2 X10 litre water containers filled with water and then weighed on accurate scales. I also used two water containers to wiegh down the saw horse end of the mast. When you tie the containers together they easily can hang over the mast to apply the 20kg weight.

I haven't managed to measure my 1997 mast yet I will post the info when I get to it.

I have measured 4 masts of the 2001-2002 vintage.

1,2 &3 have not been rigged and 4 has been sailed for 1 season.

I'll add it to your data,"0" is your mast in the table below.

MAST------0--------1---------2 -------3------4------ Range

Fore-aft: 48mm,-- 38mm, ---37 -----41---- 36---(35-45mm)

Sideways:179mm-165,-----165,----166---147-(140-170mm)

Lower mast bend-

Fore-aft: 12mm------9--------9-------9------8 -----(8-10mm)

Sideways: 47mm---38------39------41-----40---(38-48mm)



A mast will deflect under its own weight. especially in the side direction. What I measured was the increase in deflection when the 20kg weight was applied.

I tried measuring total deflection but that will measure differently depending on the tension of the string line used.

I decided measuring change in deflection by measuring the change in distanse between the scribe lines on the masts and the concrete path the saw horses were sitting on. I reasoned that this would give a more accurate comparison.





Regards,

Phill