Deploying a Drogue

[Talbot]

JSD recommend that you do not use a tripping line as this might foul the actual JSD.

[LakeSuperior]

I have thimbles spliced on the JSD and and on each bridle leg end. I then use two shackles to attach the bridle to the JSD. I also plan on using a third backup line tied to the thimble on the JSD that I can easily bring back to a winch for retreval.

This approach may be sub-optimal with all the hardware. However, surviving to get to the retrival mode seems like a good thing in the end. So the problem getting the JSD into the boat I will be happy to work by then.

I used the thimbles to preserve as much line strength as possible because near the boat is where the maximum tension will be. According to Jordan there is a possibility for extremely high forces to build on the JSD in a storm so it seemed important to make sure the bridle attachment was not the weak link.

[Talbot]

Originally Posted by LakeSuperior

I used the thimbles to preserve as much line strength as possible because near the boat is where the maximum tension will be. According to Jordan there is a possibility for extremely high forces to build on the JSD in a storm so it seemed important to make sure the bridle attachment was not the weak link.

It is not just here that you need to reinforce. The attachment point on the boat needs to be significantly reinforced to take the strain, and the lead from these attachment points for the bridle to ensure that there is no possibility of chafe.

[thinwater]

Originally Posted by delmarrey

Yeah, you are right!
The more I think about it, it makes since. A drogue/sea anchor is like a kite, the harder it is pulled, the higher/deeper it goes. Only if one were to go very slow would it be stretched out to the surface.

I only had to use my drogue once and that was when I was being towed on a short line.

All common drogues run on the surface unless wieghted, and the harder you pull, the more shallow they run.

There is no diving geometry.

I have tested quite a few.

[caribcat]

2 things that get raised in my head:
1) Why have a drogue? We have vessels that combined with the kind of weather routing we can all easily access should be able outrun a decent storm. If you could get a 24hr jump on a 100mile wide storm why would you choose to sit through it?
2) If you had to resort to a drogue do you hang it over the front or the back of the boat? One good surge backwards with spade rudders as found on most cats and you can say goodbye to them

[Flip 980]

Originally Posted by caribcat

2 things that get raised in my head:
1) Why have a drogue? We have vessels that combined with the kind of weather routing we can all easily access should be able outrun a decent storm. If you could get a 24hr jump on a 100mile wide storm why would you choose to sit through it?
2) If you had to resort to a drogue do you hang it over the front or the back of the boat? One good surge backwards with spade rudders as found on most cats and you can say goodbye to them

I agree with your point 1, on point 2 I have only used a drogue to slow down . It did 14 knots to 5. Deployed over the stern. Ferocious loads , and worrying having 600ft (I think) of line astern, with fishing boats about. Thats probably longer than was needed.

[LakeSuperior]

Originally Posted by Talbot

It is not just here that you need to reinforce. The attachment point on the boat needs to be significantly reinforced to take the strain, and the lead from these attachment points for the bridle to ensure that there is no possibility of chafe.

True enough! I am planning to have each bridle leg pass through a closed fairlead on the stern and then to a healthy cleat. Inspection of the cleat installation shows it to be adaquate, I think...

The cleat is about 1 foot from the closed fairlead. The bridle is made of modern high strength low stretch Dyneema. I think the low stretch bridle and short distance from fairlead to cleat will help to minimize chaffing. Will also use leather chaff protection.

I've got the whole kit assembled with end weight in a bag ready to deploy.

[thinwater]

Originally Posted by Flip 980

I agree with your point 1, on point 2 I have only used a drogue to slow down . It did 14 knots to 5. Deployed over the stern. Ferocious loads , and worrying having 600ft (I think) of line astern, with fishing boats about. Thats probably longer than was needed.

I would be VERY surprised and disappointed if you can't think of a dozen reasons:
* Lee shore coming up fast.
* Mechanical problems.
* Very large storm, greater than 100 miles.
* Storm moving faster than you can escape. Yes, sometimes they really go.
* Forecast changes - you ducked the wrong way, right into it.
* You would like to delay arrival because the entrances will be breaking.
* You would like some rest, particularly at night.

True, getting out the of worst is generally valid. But the only folks who believe they can dodge bullets are those that have never been hit. The best tactic will vary with the situation, boat, and crew.

[Southern Star]

Thinwater you are absolutely spot on - anyone who thinks that they can outrun every storm is asking for trouble. In terms of attachment points for a JSD, I am installing 1/4" thick, 2 "wide, 2 foot long S/S straps, through-bolted at the hull/deck joint, which will protrude just past the transoms. There will be hole at the end to fit the shackles for the bridle.

This will ensure a fair lead, eliminate chafe and provide a very strong attachment point (both the deck and hulls are solid glass at that point).

Brad

[mikereed100]

Brad,

Just a thought on straps. I have been given to understand that long s/s straps will stretch just a bit, putting more stress on the fasteners closest to the load. This is why most chainplates are now shorter and wider with a bit of a spread to the fasteners. Also, 1/4" strikes me as being a bit light, but maybe I'm just paranoid. I like the idea though, and am planning something similar on my cat.

Mike

[Ram]

I had 4 nice large round cleats made wile in Turkey (35euros) with a foot print of about 12"x 5" and have a backing plate the same size, I think I used 3/8'' or so a bolts- installed them on all for corners of the boat-set them in 5200- the back plates are about 3/16 thick maybe a little light-tested a drouge on it seems fine-