Vibrating snubber?

[hlev00]

We use a single nylon snubber on our chain rode over the bow roller. Recently we have been anchoring in a fair amount of current and found that the snubber vibrates in the current causing a very annoying rattle up in the v-berth. I’ve thought about going to two snubbers, one off each bow cleat. Unfortunately when the current reverses one often gets caught under the bow and comes up black from our bottom paint.

Any other suggestion about how to stop the vibration? (Sleeping in the aft cabin doesn’t count. )

Thanks,
Harry

[dfelsent]

Wild guess here. Have not tried this.
Violating my rule on commenting from a place of ignorance.

By adding something (a length of line hitched on?) to the middle of the snubber you may dampen the vibration.

It is essentially the same problem as singing topping lifts I am guessing.

[desodave]

Is it the snubber vibrating, or the chain being dragged across the seabed ? Our new-to-us boat sails excessively ( in a mild breeze) on a single snubber but way less on a bridle. I didn't want to set the single line over the bow roller (no center cleat) because of the angle to the forward cleat, and the likelihood of it impacting the pulpit structure. The noise up front can be sleep disturbing as (I believe) the chain on the seabed is getting dragged across rock when the boat sails at anchor ... we're in BC along a rocky Pacific coast.

Because of the plumb bow I've had to set both single snubber and bridle long enough for the chain to clear the hull when there is no wind or current, and the chain drops straight down. I haven't figured out how to stop it coming up with black from the bottom paint either - I just wear rubber gloves, try to set at a consistent length to minimize the black streak, and am careful where I put the bridle down. I coil and hang it from the chain in the anchor locker when not in use.

[Shrew]

We use two lines on our bridle. Each line is shackled to the chain hook separately.

How much snubber are you letting out? We let out just enough so that the chain hook is under water.

If the wind blows and the snubbers come tight enough to lift the chain hook out of the water, then we add a few more feet of snubber.

If the wind dies and the chain hook is dragging on the seabed or feet under water, we take some in.

[Cheechako]

You can try the double.
The weight on the snubber will likely work.
Add one of those rubber dock line stretchy snubbers in the middle should work.
It's harmonic, have you tried lengthening it or shortening it by adjusting while the vibration is going on?

[CarlF]

I agree with trying different lengths and sizes to find one without the harmonic.

Try a longer snubber with a smaller diameter. It will stretch more and absorb the energy better - also reducing the load on the anchor and chain. I use a 20ft 7/16" piece of nylon as the snubber on my 25 ton ketch. There is 15 feet of snubber from the bow to the chain. It's never broken even in 50 knot squalls. On your lighter boat you might want to try 3/8"

If I'm worried about the weather, I attach a 2nd identical snubber line tied so it is slack until the first snubber has stretched about 12".

[hlev00]

Good idea Shrew and CHeechako. The winds are nothing much here tonight, just current so a steady pull. I think that will probably stop the vibration. My only worry is that then if we get reversing current and wind the chain may drag across the bottom of the boat instead of the soft snubber. But in light conditions like we have now and overnight it is a good worth a try.

Thanks,
Harry

[thinwater]

Originally Posted by hlev00

Good idea Shrew and CHeechako. The winds are nothing much here tonight, just current so a steady pull. I think that will probably stop the vibration. My only worry is that then if we get reversing current and wind the chain may drag across the bottom of the boat instead of the soft snubber. But in light conditions like we have now and overnight it is a good worth a try.

Thanks,
Harry

Just let out more snubber. It's the length and the harmonic. I have experienced that, but never loud enough to hear it.