Mast-Pumping

[Landfall 38]

Has anyone else experienced this and what can be done to correct it to stop happening. I don't believe that boat builders such as C&C would design a boat that has this happen. Any solution to fix the problem would be greatly appreciated. Thanks

[unbusted67]

Tune your rigging?

[roger.waite]

Or running backstays, less canvas, stop whistling for wind, etc.

When is it happening?

Do you need to push her so hard?

[GeoPowers]

I've found that easing either the main sheet, boom vang, inhaul, or outhaul instantly gets rid of mast humming and pumping. I still haven't figured out which to adjust for various winds, but by a quick trial and error I can have a much quieter and more peaceful night. Usually detensioning the main sheet and/or boom vang end vibrations and pumping, but sometimes releasing the tension on the inhaul or outhaul is what works. This is easy to do on my boat as all four lines are right at the companionway hatch. I just poke my head out, adjust the lines, and I'm done in about 10 seconds. What if they are all detensioned? I pull them hand tight, and that usually works! I don't know why this works, but it does. Very rarely we still get a little mast pumping when wind accelerates in a certain direction, but this is the exception even in the windy PNW winter.

This assumes you mean mast pumping at anchor or pierside...

Quick edit: Just to clarify, we don't usually get mast pumping, just some humming. I would think that if you frequently get mast pumping, something might be wrong...

[Bash]

This is a fairly easy problem to fix, but we'll need some info. Please describe your rig in terms of: do you have running backstays?; how do you tension your backstay?; on what point of sail does the stick tend to pump?; is your stick an older C&C aluminum mast or a newer C&C carbon fiber mast?; what sort of standing rigging do you currently have?

Pictures are always helpful.

[Joli]

It's a Landfall so it is has inline spreaders. The d1"s are probably a fore and aft arraingement. To stop the pumping you have to bow the rig (? half a section?) with tension on the backstay to crank the masthead crane (excentric), pre-load the rig by shimming at the deck and posssibly use an inner forestay and runners.

[Randyonr3]

We get a certain amount of pumping in the mast while running to windward.. But our boat was built with "Check Stays" or running back stays and its a simple tighten up a little and the pumping goes away..

[Weyalan]

As mentioned above, tightening runners and / or checkstays (assuming that these are fitted) will help. Usually mast pumping is associated with strong breeze, so de-powering the main will help... initially by flattening using outhaul and cunningham, down traveller, etc. You may find that putting a reef in the main will help too.

[Landfall 38]

Thanks for all the tips. I am sorry that I didn't give more information the first time. The pumping ocures when the boat is tied up. The rigging is ss rod with one set running from mast head to deck the middle running from top spreader to bottom spreader and a for and aft under the bottom spreaders. The backstay is not a running system, it is one turnbuckle in the center. The mast does not pump when I am sailing. The mast is the older aluminim style and very heavy. The boat is also equipped with a roller furling jib.

The pumping only seems to happen when the wind is high and about 10 degrees off the port or starboard side of the bow. I have tried adjusting the rigging, however, I have not had a rod tension tunner when I am doing it. I am purchasing one this year to see if adjusting to the proper settings, not just the standard way of "feels right", makes a difference.

Don't know if this added info changes any of the previous suggestions but I thought I would add it anyway.

Thanks everyone for all your replys

[Weyalan]

It might be worth getting a qualified mast rigger to come have a look at your set-up, in case it isn't quite "tuned" correctly. Mast / rigging set-up is a fairly complicated and, in my experience, arcane art.

[barnakiel]

If the extrusion has to little support, it will be pumping given good conditions. Fine-wall extrusions with too few spreaders / stays are prone. Seen this twice.

Changing tuning / rig tension will probably help (meaning - the pumping will come at lower or higher winds), but make sure you stay within the limits. Probably best hire a rigger to do the job. Or change your mooring so that the wind comes from a different angle.

b.

[Randyonr3]

Originally Posted by Weyalan

It might be worth getting a qualified mast rigger to come have a look at your set-up, in case it isn't quite "tuned" correctly. Mast / rigging set-up is a fairly complicated and, in my experience, arcane art.

actually its not...its just a damn stick in the air held up by a few wires ..
Very easy to tune a rig..and once you learn that its not complicated, you'll tune it to the conditions of the weather.. light air, you'll losen it up and let the forstay bag a little, when the winds build, tighten it up..
Years ago while racing, The trick setup was to install a track at the base of the mast allowing you to push the base forward and rake the mast aft on the starting line for power comming out of the hole and then pull it back into place once you picked up speed.. worked just like shifting gears.
with a little experance, you can walk up to your rigging and give it a pull and tell if its adjusted right..