Mast whip/vibration

[Roger]

Hello all.

I tried this in the Tiki 21 group but didn't get any traction, so I'll try again here. I get a bit of mast whip (alu mast) when the rig is loaded up on certain points of sail - I think mainly upwind. With no sails up it is pretty easy to get the mast whipping by pushing and pulling it. It doesn't cause any problems, but can anyone tell me if this is typical for the Tiki 21, or for the smaller Tikis in general with the short masts without any spreaders?

Thanks,

Roger

[kim whitmyre]

Roger,

I haven't experienced this on my tiki 26, Vaea.  My mast still has about 5' of wood at the foot, with the rest being 1/8"x5" aluminum tube, 27' high.  Do you know the wall thickness of your mast? 

Have you tried tightening up the standing rigging yet?

Let me clarify my that I am talking about mast whip.  Sitting at the slip on a breezy day, I can feel the standing rigging vibrate a bit.

[Roger]

Hi Kim,

Thanks for the feedback. The standard alu mast section for the 21 is 4' and 1/8" wall thickness. My mast is a bit under 4' at 3' something, but is double wall thickness at 1/4". It will be interesting to hear from a Tiki 21 sailor with an alu mast.

Roger

[Roger]

PS I get my rig really tight with a big 4:1 purchase on the fore stay. In fact, it only vibrates when I have it really tight. Maybe I'm overdoing it?

[paul anderson]

Roger,could you be getting what they cal l'' resonance'' ?

[Roger]

Hi Paul,

yes, I think that's quite possible.

Roger

[kim whitmyre]

Dial it back a notch, Roger, and see what happens. I take two halyards to the bow/stern(at separate times) and snug them up a bit, then I take a line and "frap" the halyards as high as I can reach. This pulls the mast towards the respective end, and then I tighten the lashing, and release the halyards. It may be that the 4:1 purchase allows you to overtighten the rigging.

[Roger]

Thanks Kim. Yes, I can experiment with less tension. The good thing is that I can tighten the rig until the side stays become tight, and the boat goes to weather very well. I would still like to hear from another Tiki 21 owner if the mast whip is just a characteristic of the 4' mast.

[Rick Hueschen]

Hi Roger,

What is the diameter of your mast? From looking at your pictures, the mast appears to have a smaller cross section. I built the standard wooden mast with a four inch cross section according to the plans and have no problem with mast whip.

Rick

[Roger]

Hi Rick,

You are right - the section is closer to 3' but with double wall thickness at 1/4".

Roger

[peter logan whitehouse]

hi roger,

i have a tikki 21 with standard rig. sounds like you are too tight on your rigging. mine are not much more that hand tight.

Sounds like that will be vibrating in a 'B sharp'

[Roger]

Thanks for the feedback Peter - alu mast or wood?