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Old 04-02-2016, 11:56   #16
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Re: Multihull bridle attachment

Hi, looking at the drag device database in another thread I ran across the following statement with regard to the bridle. Does anybody have any experience if there is such a big difference in the bridle attachment being right on the bow or 2 meters backwards?

http://dragdevicedb.com/sea-anchors-...rimaran-kismet

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Old 04-02-2016, 12:21   #17
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Re: Multihull bridle attachment

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Hi, looking at the drag device database in another thread I ran across the following statement with regard to the bridle. Does anybody have any experience if there is such a big difference in the bridle attachment being right on the bow or 2 meters backwards?

S/T-2 Trimaran, Kismet | Victor Shane's Drag Device Data Base

Attachment 118298
I've been using a mooring bridle since 2001 on my trimarans, attached the "wrong" way as in the image you linked. I attach my bridle to reinforced forward-facing U-bolts at the outer ends of the fore crossbeams.

It seems to be doing well after 15 years. If the image hadn't said it's wrong I wouldn't have known.

The boat's on the hard for the winter but I may try an attachment to the outer bows at some point, as an experiment.

PS -- I often see boats that fly extra headsails on furlers, and that adds a lot more windage forward and can lead to mast pumping in a seaway. I don't think it's a good idea to keep screachers hoisted on continuous line furlers when you aren't using them.
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Old 04-02-2016, 13:52   #18
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Re: Multihull bridle attachment

Quote:
Originally Posted by Tri View Post
Hi, looking at the drag device database in another thread I ran across the following statement with regard to the bridle. Does anybody have any experience if there is such a big difference in the bridle attachment being right on the bow or 2 meters backwards?

S/T-2 Trimaran, Kismet | Victor Shane's Drag Device Data Base

Attachment 118298
Maybe attaching to the bow gives a wider bridle stance, but I would think that attaching it closer to a bulkhead or post to take the compression set up by the bridle would be better (ie, aft).
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Old 04-02-2016, 14:24   #19
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Re: Multihull bridle attachment

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Originally Posted by SVNeko View Post
Maybe attaching to the bow gives a wider bridle stance, but I would think that attaching it closer to a bulkhead or post to take the compression set up by the bridle would be better (ie, aft).
A well designed multi should have very strong points at the bow either on the boat or on the end of the forebeam to attach anchor (ground and sea) points. If if doesn't have them then it would be worth building them before a long passage. with regard to the wider stance, I don't think its about wider stance, its about not having lateral resistance forward of the attachment point. with the points aft particularly on a skinny hull tri, you are effectively created a balanced rudder of sorts, from the hulls
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Old 04-02-2016, 14:25   #20
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Re: Multihull bridle attachment

Hi SailFastTri, yes the U-bolts on your DF come by the manufacturer and that is where I have my bridle attached as well. I have been wondering though because the boat is sailing a lot at anchor or mooring and I did try to understand or find out why. From previous catamaran experience I must say I never had a sailing around issue at anchor but that might have been because they were much heavier boats. Trying to understand the issue on the tri it also came to my mind that it might make sense to try and move the attachment points further forward but I didn't follow up on it because the bolts at the top of the bow are much weaker (broke one already) than the U-bolts on the beams and frankly it is more of a hassle to rig the bridle all the way at the tip of the amas in wavy conditions. However, reading the article I posted that made me rethink again.
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Old 04-02-2016, 14:57   #21
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Re: Multihull bridle attachment

Quote:
Originally Posted by SailFastTri View Post
I've been using a mooring bridle since 2001 on my trimarans, attached the "wrong" way as in the image you linked. I attach my bridle to reinforced forward-facing U-bolts at the outer ends of the fore crossbeams.

It seems to be doing well after 15 years. If the image hadn't said it's wrong I wouldn't have known.
I have always attached my anchor bridle at the ama tips, never tried off the ama eyes. Hmmmm...
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Old 04-02-2016, 15:05   #22
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Re: Multihull bridle attachment

:-)

From personal experience (breaking one) my fear would be will they take the load in bad conditions?
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Old 04-02-2016, 22:12   #23
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Re: Multihull bridle attachment

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:-)

From personal experience (breaking one) my fear would be will they take the load in bad conditions?
Breaking what? Not clear.
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Old 05-02-2016, 07:07   #24
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Re: Multihull bridle attachment

At the very tip (front) of the bow of the amas there is a u-cleat that stands up (where the fixture for the bowsprit is attached). That was bend to the side once when in port.

For the DF the beams are baked vinylester and much stronger in comparison to the hull of the amas. The u-cleat at the beam seems to be more suitable also from a reachability perspective.

I am therefor not sure if the u-cleats at the tip of the bow are a good idea to attach the bridle even if they might be positioned a lot better to prevent sailing at anchor.

But I would be very interested in Senormechanico's experience, especially when there is a lot of pressure on the bridle and also from a sailing at anchor perspective. Thanks.
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Old 05-02-2016, 07:20   #25
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Re: Multihull bridle attachment

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At the very tip (front) of the bow of the amas there is a u-cleat that stands up (where the fixture for the bowsprit is attached). That was bend to the side once when in port.

snip.
You must have had quite a load on that fitting.

On Dragonfly's the u-cleat you bent is made for two purposes:
1) to attach a block for a secondary spinnaker tack control line, which would enable you to pull the tack to windward when running deep.
2) to attach a sprit stay to keep the sprit from moving to leeward.
3) attach a dock line

The only way I'd use that attachment on a bridle would be to use a swivel bale with turning block on it, and a control line (as in #1 above) to attach to a bridle line attached to the outer end of the ama... I'd use a snatch block or soft shackle to attach the control line to the bridle line, and adjust the control line from the safer area near the front of the net, or from the bow (you could use a bow cleat to tie it off).
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Old 05-02-2016, 08:06   #26
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Re: Multihull bridle attachment

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Originally Posted by SailFastTri View Post
-----On Dragonfly's the u-cleat you bent is made for two purposes:
1) to attach a block for a secondary spinnaker tack control line, which would enable you to pull the tack to windward when running deep.
2) to attach a sprit stay to keep the sprit from moving to leeward.
3) attach a dock line

The only way I'd use that attachment on a bridle would be to use a swivel bale with turning block on it, and a control line (as in #1 above) to attach to a bridle line attached to the outer end of the ama... I'd use a snatch block or soft shackle to attach the control line to the bridle line, and adjust the control line from the safer area near the front of the net, or from the bow (you could use a bow cleat to tie it off).
I'm slow this morning. What does the "control line" control? If you are using a snatch block in a forward bow position why not just run the bridle through it and back to the cockpit winch/cleat in case you need to adjust for chafe, etc.? Needs some extra length on the bridle but I would want that anyway.
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Old 05-02-2016, 11:20   #27
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Re: Multihull bridle attachment

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I'm slow this morning. What does the "control line" control? If you are using a snatch block in a forward bow position why not just run the bridle through it and back to the cockpit winch/cleat in case you need to adjust for chafe, etc.? Needs some extra length on the bridle but I would want that anyway.
The control line can pull on the spinnaker tack -- to enable it to be pulled to windward and that gets more of the sail out from beyond the lee of the main. That same line could be loosely attached along the bridle (using a snatch block or soft shackle) and allow adjustment of the bridle spread by pulling the legs toward the bows.

My bridle legs are each spliced to a very large snap hook (SWL about 4 Kilos as I recall) and attach to a well-backed U-bolt, so I don't worry about chafe.
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Old 05-02-2016, 12:32   #28
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Re: Multihull bridle attachment

Would be interesting to hear about Senormechanico's ecperience in practice.
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Old 05-02-2016, 13:24   #29
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Re: Multihull bridle attachment

I just tied the bridle to the ama tips with bowlines (stitched for security).
When sailing, I pull it up through and over the bow pulpit and secure it to an s.s. ring. See phone photo below.
Having it hanging across the boat all the time has its advantages when docked as it prevents kids (and adults) from trying to paddle under our boat in their kayaks.

The middle of the bridle has a short length of line attached which is secured to the anchor rode (35' of chain then rode) with a rolling hitch or Gripping Hitch.
The boat doesn't sail at anchor until we see around 15 knots or so, and even then it is fairly minimal.

I don't use the bridle for the tack of the cruising spinnaker. That's the job of the barberhaul lines.
When flying a symmetrical chute, I attach the barberhaul lines through those same blocks from the same ama tips for foreguy controls.

The top photo is gripping hitch from Wikipedia, and the second is my bridle arrangement.


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Old 05-02-2016, 20:44   #30
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Re: Multihull bridle attachment

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Originally Posted by SailFastTri View Post
The control line can pull on the spinnaker tack -- to enable it to be pulled to windward and that gets more of the sail out from beyond the lee of the main. That same line could be loosely attached along the bridle (using a snatch block or soft shackle) and allow adjustment of the bridle spread by pulling the legs toward the bows.

My bridle legs are each spliced to a very large snap hook (SWL about 4 Kilos as I recall) and attach to a well-backed U-bolt, so I don't worry about chafe.
I don't see what an anchor bridle has to do with a spinnaker.
I also don't see what a snap hook and a U-bolt have to do with chafe protection.
You don't have any chafe guard material on your bridle? Or does your bridle not touch anything?
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