Swinging in the wind

[fins1up]

We're in a fresh water lake and spend many hours at anchor enjoying life. One problem I seem to have more than others is how our boat swings while the hook is down. The anchor stays put and we don't drift, but we do seem to move around more than other boats nearby. I've tried shorting the rode, increasing the rode, cranking the outdrives to either side, etc. We're usually in 20 - 30 feet of water. I have 20' of chain connected to the anchor then rope the rest of the way. Short of setting a second anchor off of the stern, any other suggestions on what I may try?

 

[Henry Boyd]

You can also try raising the drives. But it may just be the way the boat is loaded. I have a friend whose sailboat has been spinning around the anchor, or mooring for the past 20 years.

If it bothers you, or causes problems where you anchor, setting down a stern anchor is a good solution. We often do it to avoid swinging too far during a tide direction change. The anchor does not have to be huge. We use an aluminum fortress, one size down from what we would need as the main anchor. You probably could get by with no to maybe two feet of chain. I would also suggest you put a small line 1/4" ish and float on the anchor. It will warn passers by you have an anchor out, and if the anchor gets stuck, you can just drop the rode in the water, raise the forward anchor, and then go retrieve the stern anchor.

In the front you want all of the chain on the bottom.

Henry

 

[Four Suns]

This was discussed here:

http://clubsearay.com/forum/showthread.php?p=181605&highlight=sail#post181605

but here is the post so you don't have to wade through all of the wingless BS that was on that post:

Scope was 5 to 1 in 9 feet off water = ~50 feet. Couldn't go much longer as the cove is narrow (about 150 feet) and the boat ALWAYS sways back and forth sideways, slowly about 40 feet. Why does it do that? You'd think it would just pull downwind. :huh:

Sometimes bigger and uglier on the anchor is not the answer (and sometimes ugly squared).

The boat swinging like a pendulum on the hook is caused by the boat sailing upwind. I drew a little diagram on my Mac here for you:

The turbulence around the boat will orient the boat with a side to the wind at some point which will begin a process where the boat will literally sail upwind until the anchor line pulls the nose over into the wind enough and then the boat rotates and sails back the other direction basically repeating the process over and over like a big pendulum on a grandfather clock. If you have a bridge boat, the problem is worse. If you have an aerodynamic body like a sailboat, the problem is worse.

The fix is to use an anchor snubber or anchor bridal where it hooks on a side cleat up by the bow:

When the boat tries to rotate to start sailing upwind, the force is transferred to the side cleat to rotate the boat back into the wind so it won't sail.

I didn't draw this picture but this is what it looks like:

You can buy them... or make one.. I made mine...

A boat swinging in the wind like this can introduce several hundred pounds of additional force on the anchor (and not in-line with the anchor) and break just about any anchor free if the wind is strong enough and the boat is working in perfect harmony. Also, the longer you make the anchor rode, the worse the swinging becomes.

Another option, which is essentially shortening the rode but keeping the anchor line at the correct angle to the sea floor is to put anchor rode weights on the rode itself. I've never done that but know sailors that do... That also helps the swinging.

I have an all chain rode and have a horrible swinging problem if I don't use a snubber on the front. One time I ducked into a cove to avoid a squall with 60 knot winds in it and the boat was swinging so bad I almost went into a sea wall after dragging probably 500-600 feet. Some boats did hit the wall... I was lucky that day. I didn't have time to put the bridal on... and something about holding on the front of the rail with an anchor hitting ground and lightning all over the place made me jumpy.

 

[Henry Boyd]

Gary,

I read through all of the wingless stuff, it was quite comical, I can't believe I missed it when it was happening. I'd make a couple of comments. One, 280's are rope and chain, attaching a snubber is problematic. Two, judging by the way our 280 dances on its mooring with twin pennants (and a stern line & block) suggests to me that the distance between the cleats is insufficient to create a large enough angle to make a difference.

I'm not disagreeing with your analysis as a general case, but I think with the physical specifics of the 280, a stern anchor may be the more practical solution to the problem.

Henry

 

[firecadet613]

I'd be very interested in finding a solution to this, we were swinging pretty good this morning, compared to other boats anchored not to far away from us....

 

[fresh water]

This was discussed here:

http://clubsearay.com/forum/showthread.php?p=181605&highlight=sail#post181605

but here is the post so you don't have to wade through all of the wingless BS that was on that post:



Sometimes bigger and uglier on the anchor is not the answer (and sometimes ugly squared).

The boat swinging like a pendulum on the hook is caused by the boat sailing upwind. I drew a little diagram on my Mac here for you:

The turbulence around the boat will orient the boat with a side to the wind at some point which will begin a process where the boat will literally sail upwind until the anchor line pulls the nose over into the wind enough and then the boat rotates and sails back the other direction basically repeating the process over and over like a big pendulum on a grandfather clock. If you have a bridge boat, the problem is worse. If you have an aerodynamic body like a sailboat, the problem is worse.

The fix is to use an anchor snubber or anchor bridal where it hooks on a side cleat up by the bow:

When the boat tries to rotate to start sailing upwind, the force is transferred to the side cleat to rotate the boat back into the wind so it won't sail.

I didn't draw this picture but this is what it looks like:

See... If I had read the original poster's info, I wouldn't have posted that "all chain" non-sense...

Not read OP both times? "I have 20' of chain connected to the anchor then rope the rest of the way." Grabber hook and snubber on rope?

 

[fins1up]

This was discussed here:

http://clubsearay.com/forum/showthread.php?p=181605&highlight=sail#post181605

but here is the post so you don't have to wade through all of the wingless BS that was on that post:



Sometimes bigger and uglier on the anchor is not the answer (and sometimes ugly squared).

The boat swinging like a pendulum on the hook is caused by the boat sailing upwind. I drew a little diagram on my Mac here for you:

The turbulence around the boat will orient the boat with a side to the wind at some point which will begin a process where the boat will literally sail upwind until the anchor line pulls the nose over into the wind enough and then the boat rotates and sails back the other direction basically repeating the process over and over like a big pendulum on a grandfather clock. If you have a bridge boat, the problem is worse. If you have an aerodynamic body like a sailboat, the problem is worse.

The fix is to use an anchor snubber or anchor bridal where it hooks on a side cleat up by the bow:

When the boat tries to rotate to start sailing upwind, the force is transferred to the side cleat to rotate the boat back into the wind so it won't sail.

I didn't draw this picture but this is what it looks like:

You can buy them... or make one.. I made mine...

A boat swinging in the wind like this can introduce several hundred pounds of additional force on the anchor (and not in-line with the anchor) and break just about any anchor free if the wind is strong enough and the boat is working in perfect harmony. Also, the longer you make the anchor rode, the worse the swinging becomes.

Another option, which is essentially shortening the rode but keeping the anchor line at the correct angle to the sea floor is to put anchor rode weights on the rode itself. I've never done that but know sailors that do... That also helps the swinging.

I have an all chain rode and have a horrible swinging problem if I don't use a snubber on the front. One time I ducked into a cove to avoid a squall with 60 knot winds in it and the boat was swinging so bad I almost went into a sea wall after dragging probably 500-600 feet. Some boats did hit the wall... I was lucky that day. I didn't have time to put the bridal on... and something about holding on the front of the rail with an anchor hitting ground and lightning all over the place made me jumpy.

Thanks for the info. I especially liked the photos. At least I now know I'm not the only one who is dealing with this. I was thinking about switching to an all chain rode, but yesterday I watched a 36' something with all chain doing the same thing I was. Your post confirmed it's not just a matter of the rode. We have some shallow coves in the area where I can anchor and play with the snubber idea even though I only have 20' of chain to work with. Might be just as easy to pitch out a stern anchor, but I see what we can come up with. Thanks again for the ideas.

 

[Four Suns]

Not read OP both times? "I have 20' of chain connected to the anchor then rope the rest of the way." Grabber hook and snubber on rope?

Look wingtard... you were voted off the island and why you insist on coming back shows you must be really be bored. Go back to thehulltruth where you can put a copyright by all your pontificating.

wingtard... you are so f*cking smart... I hear they can now do penis transplants... go get one.

 

[Turtlesboat]

I especially like how he tries to hide his obvious writing style with broken sentences.

 

[katricol]

how do you guys know?

 

[Four Suns]

Go look at his posts... he keeps referring to his old... I mean wintards posts and talking how great they are. Oh! and he's an expert in 380 DA's!!! Imagine that!

 

[fresh water]

wingtard... you are so f*cking smart... I hear they can now do penis transplants... go get one.

Very bad words. Very very bad man!

 

[Turtlesboat]

Aren't you supposed to be banned?

 

[fresh water]

Go look at his posts... he keeps referring to his old... I mean wintards posts and talking how great they are. Oh! and he's an expert in 380 DA's!!! Imagine that!

Not true. See.

Wing bad. Wing words bad. Bad bad bad.

Only ask about Wing MOB safety drill. Found good info better place.