SHAKING on my cradle ... Newport28

[SURV69]

Well, I left the mast up this year. The yard allows the mast up, on a cradle only.

The winds are gusting in the upper 20's and I think if I were to stand perfectly still, in the galley, with a pitcher of cream, I could make butter.

Maybe I should see about removing the mast ... ?

[Mike OReilly]

What's moving? The hull on the cradle, or is the mast pumping? Or is it the rigging?

If it's shifting on the cradle then you might have a problem. Are you seated well? Snugged in? Does the cradle provide adequate support? You could add some jack stands for additional support.

If it's the mast pumping or the rigging moving, then I'd tighten things up. I assume you've taken the sails off. This would have reduced the load on the rigging, which might mean it is now too loose.

BTW, I've left the rig up and down over the years, on jack stands and on a cradle. I prefer jack stands, but our boat is a big, heavy full-keeler.

[delmarrey]

Actually, if the mast is pumping you want to loosen things up meaning the back stay and halyards. A stiff mast will sing like guitar strings.

[SURV69]

the mast is not pumping, but I think the cradle is flexing.

It feels like the boat is moving an inch or so, back & forth, but I shined a light on the next boat(Bristol 29 on a very heavy-duty cradle, and the degree of movement appears to actually a very small fraction of an inch, when I sight a marked sport on my deadlight onto a marked spot on the other boat ... about 5 feet away.

On a calm day, I can actually feet the boat "twitch", when my cats jump around.

So much for a cradle made with 4" channel iron and 4" squares for uprights.

It's kinda scary, and kinda exciting ... like ... Halloween ...

[delmarrey]

I'd suggest keeping an eye on the welded joints. At Dagmar's where I was for 10 years they had one cradle lose a leg during a wind storm. The boat did lean hard but managed to stay up with minor oil canning to the hull.

[Mike OReilly]

Originally Posted by SURV69

the mast is not pumping, but I think the cradle is flexing.

It feels like the boat is moving an inch or so, back & forth, but I shined a light on the next boat(Bristol 29 on a very heavy-duty cradle, and the degree of movement appears to actually a very small fraction of an inch, when I sight a marked sport on my deadlight onto a marked spot on the other boat ... about 5 feet away.

On a calm day, I can actually feet the boat "twitch", when my cats jump around.

So much for a cradle made with 4" channel iron and 4" squares for uprights.

It's kinda scary, and kinda exciting ... like ... Halloween ...

Your first measure sounds OK to me in 20+ knots, but then you say the boat is "twitching" when the cat jumps around ... that sounds not good to me. I've never felt any of my boats twitch under a cat's movements. Is the keel well seated? Is the cradle wide enough? Are the pads making solid contact?

I'm pretty sure your cradle is fine for a 28' boat, but it should not be moving under the weight of a cat (unless you have a really big cat ). You could consider setting some anchors into the ground to add stability if nothing else will help. A bow jack stand might help if the balance if off.

delmarrey, pumping to me means the mast is moving in its step. Maybe we're talking about something different. Of course it should not be guitar-string tight, but even if it is, I've never seen a mast sing. Stays and shrouds, sure. Mast? Not in my experience, and we get some pretty ugly winters up here on the north shore of Lake Superior.

[delmarrey]

There's a boat on the hard in the Napa marina that every time the wind picks up the mast starts humming. And the stronger the wind, the louder it gets. Also, a Ranger 40 in Everett where I was was, is backed into the slip against the wind, and the same thing but it puts out a pretty good tune when the afternoon winds pick up. One of those inmast furlers.

And pumping, from what I've leared is the mast flexing or bending, like with an inner foresail w/o running back stay.

http://www.cruisersforum.com/forums/...tml#post299846

[SURV69]

Well, the wind gusts kicked to the upper 40's, last night ... now the winds are into the 20's with gusts into the lower 30's, with a gust now and then seeming into the high 30's.

I'm still here though.


Cats ... in years past, on a cradle(other cradle), with mast down, and on stands, with mast down, cat jumps onto the boat, or inside the boat, always could be"felt", by me, although I think that any time I was on a cradle, I would notice the jump more.

I'm sure(I think), that any cradle that is not overly strong, will(could, might), telegraph the jumps of 12 pound cats ... I ... hmmm?

[Cadence]

Originally Posted by SURV69

Well, I left the mast up this year. The yard allows the mast up, on a cradle only.

The winds are gusting in the upper 20's and I think if I were to stand perfectly still, in the galley, with a pitcher of cream, I could make butter.

Maybe I should see about removing the mast ... ?

I think I would look a shims. Sounds as if the boat has movement in the cradle or the cradle is moving on the ground. If it is that severe I doubt it is just the mast humming.

[zeehag]

anchor the boat and cradle to earth with 4 anchors one on each corner.
shim what may need shimming, and it should be more relaxing.

[SURV69]

I appreciate the shimming idea, especially so, since the 6' by 12 cradle is made of 4" channel iron.

I put a shim under the keel before the winds hit since the cradle had a slight bow down in the middle.

Maybe that's why I rode out what I thought were 30
+mph, only to find out the wind gusts were nearly 50 mph.

I'll look for another shim to put under the keel tomorrow.

The first shim was placed somewhat loose with a hand-shoved wedge to give it decent(not too firm), contact. I'll see it it tightened up tomorrow.

thanks

[Cadence]

Originally Posted by SURV69

I appreciate the shimming idea, especially so, since the 6' by 12 cradle is made of 4" channel iron.

I put a shim under the keel before the winds hit since the cradle had a slight bow down in the middle.

Maybe that's why I rode out what I thought were 30
+mph, only to find out the wind gusts were nearly 50 mph.

I'll look for another shim to put under the keel tomorrow.

The first shim was placed somewhat loose with a hand-shoved wedge to give it decent(not too firm), contact. I'll see it it tightened up tomorrow.

thanks

I'm not sure shimming the keel is the answer, even if the cradle has you suspended. It may even make it worse. I'd look for slack between the hull and the cradle or the whole cradle rocking. The former post about anchoring the cradle may well be the answer.