Drogue to reduce swinging

[Rich J]

My plumb bow trawler would swing 120 degrees at anchor with 5.1 all chain with a rope bridle i 20knot breeze.

A 40 inch diameter drogue reduces swinging to 40 degrees.

The drogue attaches to a chain link just below the bridle..I switched to a swivel hook to control twisting


The drogue has a kids hula hoop cable tied in the throat a small float is at the apex
This keeps it horizontal and reverses quickly after changing direction swinging

 

[Simi 60]

Thats a pretty big drogue, 1m diameter.
What size vessel?

 

[Mako]

How much do you swing if you attach a single snubber off-center instead of presenting your bow on?

 

[rslifkin]

Anything that gets the center of effort for wind behind the center of effort for underwater drag will help the boat sit better in the wind.



If it's anything like my boat, the bow blows off badly enough that if the wind is even a little bit gusty, the stretch in the rode is enough that it'll sail around just as much cleated off-center unless you keep the boat at a 45+ degree angle to the wind.

 

[Rich J]

Boat info

my boat is a Greenline 33
It has two skegs seven feet forward of the rudder. This lateral resistance in the aft 1/3 of the boat is good underway but causes instability at anchor.
Florida thunderstorms and gusts make anchoring off the Quarter risky.

QUOTE]

My plumb bow trawler would swing 120 degrees at anchor with 5.1 all chain with a rope bridle i 20knot breeze.

A 40 inch diameter drogue reduces swinging to 40 degrees.

The drogue attaches to a chain link just below the bridle..I switched to a swivel hook to control twisting


The drogue has a kids hula hoop cable tied in the throat a small float is at the apex
This keeps it horizontal and reverses quickly after changing direction swinging

 

[O C Diver]

My boat can sail terribly at anchor in the right conditions. My simple solution is a drag weight off the bow. When the bow drops off wind, the boat sails in the direction unit it reaches its limit and then reverse, sometimes with a back step. Putting the drag weight down with a little scope (only enough to keep the weight completely on the bottom), slows the bow down so it doesn't go as far off wind and allows the stern to catch up quicker. It won't stop the swing completely unless the boat can't drag it.

While I've never had an issue with it fouling my anchor, I don't tend to use it where reversing tidal currents are normal. My boat doesn't tend to sail much in current, so it's not really necessary.

30 pounds of diver weights on some webbing works pretty well on my boat.



I also use this when waiting for bridges or locks. It either holds you in place, or it's a slow drag. In this application, scope makes a BIG difference.

Good idea to have a 5 gallon bucket handy when you recover it. The weight can get pretty nasty dragging in the mud all night.

Ted

 

[Marco Flamingo]

I first tried a drogue off the stern. As the swing changed from one direction to the other, the slack in the line allowed for about 15 feet of travel without any effect of the drogue. This allowed the boat to have enough momentum that the drogue didn't have much effect once it got tight again. Plus, the swing was slow enough that the drogue didn't put much of a tug on the stern.

So I put it off the bow by attaching it to the anchor chain just below the surface. That appeared mainly to change the point of rotation. Instead of swinging back and forth from the anchor, it swung back and forth pivoting on the drogue. It shut down the amount of swing by 20 degrees, but that's not much when the boat is swinging through 140. Trials continue.

These tests were in harbors with no current. Current on the keel and drogue straightens things out, but can have its own problems.

It is also possible to learn to live with it if the swing is slow enough. I never feel a tug, just changing scenery. That's not horrible.

 

[backinblue]

Any way to rig a riding sail aft of your mast? They've worked great for me on sailboats and kept my boats arrow-straight into the wind.

 

[Slowmo]

My boat can sail terribly at anchor in the right conditions. My simple solution is a drag weight off the bow. When the bow drops off wind, the boat sails in the direction unit it reaches its limit and then reverse, sometimes with a back step. Putting the drag weight down with a little scope (only enough to keep the weight completely on the bottom), slows the bow down so it doesn't go as far off wind and allows the stern to catch up quicker. It won't stop the swing completely unless the boat can't drag it.

While I've never had an issue with it fouling my anchor, I don't tend to use it where reversing tidal currents are normal. My boat doesn't tend to sail much in current, so it's not really necessary.

30 pounds of diver weights on some webbing works pretty well on my boat.

View attachment 122583

I also use this when waiting for bridges or locks. It either holds you in place, or it's a slow drag. In this application, scope makes a BIG difference.

Good idea to have a 5 gallon bucket handy when you recover it. The weight can get pretty nasty dragging in the mud all night.

Ted

Just so I understand, this is like a sentinel hanging from the anchor rode? If so I used one for decades, about a 50lb lead weight that was lowered about halfway down the anchor rode to reduce scope. Worked well but it is important that it NOT touch the bottom otherwise you the risk of the the sentinel line wrapping around the anchor rode - resulting in a mess and difficulty retrieving.

 

[O C Diver]

Just so I understand, this is like a sentinel hanging from the anchor rode? If so I used one for decades, about a 50lb lead weight that was lowered about halfway down the anchor rode to reduce scope. Worked well but it is important that it NOT touch the bottom otherwise you the risk of the the sentinel line wrapping around the anchor rode - resulting in a mess and difficulty retrieving.

No, it's deployed out of one of the bow hawse pipes and cleated off. I have never had it tangle with the anchor chain which stays forward of it.

Ted

 

[Marco Flamingo]

Any way to rig a riding sail aft of your mast? They've worked great for me on sailboats and kept my boats arrow-straight into the wind.

My mast is a fairly thin hollow fiberglass shell without stays. I'm a little spooked of just having the radar up on the mast. By the time a stay sail would have enough force to straighten the boat it might be too much for the mast.

 

[Shrew]

Boats wag. You're solving a problem that doesn't really exist. It's like trying to keep the boat from rocking.

 

[skyhawk]

why not a small stern anchor?
just a small boat guy here...so maybe a dumb question....but it's what I would do if I was trying to keep a boat from swinging..... conditional of course on the situation

 

[rgano]

Rich J, any hope of a photo of your innovative rig?

 

[rslifkin]

why not a small stern anchor?
just a small boat guy here...so maybe a dumb question....but it's what I would do if I was trying to keep a boat from swinging..... conditional of course on the situation

Unless it's small enough to drag very easily, that prevents the boat from staying pointed to the wind if the wind shifts. Adding drag in the water up forward doesn't, it just makes it harder for the bow to fall off and send the boat sailing until it hits the end of the rode and tacks back the other way.



On some boats, the behavior isn't a big deal, on others it's bad. In winds blowing low 20s gusting to 30-ish with slightly shifty direction on the gusts, I've seen my boat make better than 1.5 kts over ground at anchor.

 

[Shrew]

why not a small stern anchor?
just a small boat guy here...so maybe a dumb question....but it's what I would do if I was trying to keep a boat from swinging..... conditional of course on the situation

Because if there are other boats around, then every needs to put out a stern anchor. Otherwise, when the wind or tide shift, everyone will swing 180 degrees except the boat with the stern anchor. He will be in his neighbors way.

 

[Rich J]

Picture of drogue with hula hoop and small floatIn attached files

 

[rgano]

Nice, thnks.

 

[skyhawk]

Because if there are other boats around, then every needs to put out a stern anchor. Otherwise, when the wind or tide shift, everyone will swing 180 degrees except the boat with the stern anchor. He will be in his neighbors way.

yeah... I get that. that's why I said conditional.....
I was thinking more to marco flamingo's post when they wrote even with such a drogue they get too much swing.

I was thinking....again depending on the situation, bottom type, setting, etc.......could be simple thing like OC Diver's weights that might just drag the bottom with roughly a 1:1 scope deployed off the stern....or a small "dingy anchor" with more scope for a more proper stern anchoring.... or even something more....depending

obviously might have to be monitored, especially if wind and current swings 180° or 360°, etc...

 

[GoneFarrell]

Rich J, I like it!

Can you suggest a source for the drogue, thanks!

 

[Rich J]

Drogu and kids hula hoop

Amazon has multiple sizes of drogues mine had the same diameter as kids hula hoop

 

[timb7734]

I use a light claw anchor dropped off the stern to just sit on the bottom. Works well unless the wind comes up over 15 knots, then just let her sail!

 

[Rich J]

Drogue source

Amazon has multiple drogue and kid hula hoop
Look for 1 meter or slightly larger throat if you use kids hula hoop also on Amazon