Deck cleats

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This topic contains 12 replies, has 7 voices, and was last updated by Richard Garlant Richard Garlant 7 months ago.

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September 23, 2010 at 10:50 #4601
Richard Garlant
Richard Garlant
Participant

I am a little worried about the strength of the aft deck cleats should we need to deploy a drogue or sea anchor. Luckily I have never used either but wondered if anyone has and if so were the cleats adequate?

September 23, 2010 at 11:00 #7421
Alexina
Alexina
Participant

Hi Richard,

We are in the process of building a Jordan series drogue which I intend deploying from the aft cleats. I had assumed that they would be strong enough but now you mention it I am thinking again, If anyone has any experience I would be very grateful.

Peter

September 23, 2010 at 16:21 #7441

Helene de Mer
Participant

Hi !!

If it was my boat, then I would nor be worried about aft deckcleats which I would only use for trailing warps. If the weather was really bad then I would prefer to lie bow to with a drouge and have it attached around the bottom of the mast. Jan

September 23, 2010 at 16:24 #7451

Helene de Mer
Participant

Another point to consider is that although it is not usual for centre cocKpit boats to be “Pooped” in bad weather, over 45 knots, I would still prefer to lie Bow to. Jan

September 23, 2010 at 23:33 #7471
svgosling
svgosling
Participant

Care should be taken with all deck cleats if they have never been re-bedded. Shortly after we bought Gosling (C&N 42) I popped one of the deck cleats forward when using it for a main boom preventer. Close inspection revealed that 2 of the 4 stainless bolts holding it down had rusted through leaving only the heads in place. The remainder were badly eroded. Following that experience I removed and re-bedded the remainder of my deck fittings and found many in the same condition.

Regarding the drogue issue. I agree with mounting it to keep the bow to windward. When the weather and seas are that rough that you have to deploy a drogue you are not sailing anymore and the last thing you need is waves crashing in from astern.
J-G
SV Gosling C&N 42 #6

September 24, 2010 at 11:48 #7501
michael bennett
michael bennett
Participant

The use of the mast sounds ok to trail a drogue from, but even better i feel is a bridle from the primary winches, they are, or should be very secure.

Mike

September 25, 2010 at 06:26 #7521
Van
Van
Participant

It’s interesting to read the background for the Jordan series drogue. His design goal was to enable a boat (monohull) to survive a rare “worst-case breaking wave”, which he claimed was the cause of most dismastings and lost boats in storms – he also claims non-breaking waves, even in hurricane force winds, are not a real threat to well found monohulls.

His argument is summarized here:
http://oceanbrake.com/jordan'snotes.html

From the above web site:
“A monohull is directionally unstable when moving backward because the center of pressure of the underwater surface is behind the center of gravity. As any skipper knows, it is possible to run off before a storm – but it is not possible to run off backwards as the boat will yaw.”

The point he’s making is that whether you are using a drogue or sea parachute from the bow, you will be moving **backwards** through the water. Given how badly the C&N 38 moves in reverse, I can only assume it is really unstable in that direction and would yaw badly, frequently being broadside to the waves and wind. However, the boat is stable moving forward through the water with the wind behind, as it would be if using a stern-tied drogue.

He also claims that in the event of a breaking wave, the bow will bury itself in the wave – while he claims the stern is not as likely to do that. On the C&N 38, we have quite a lot of bouyancy in the stern (engine in the center of boat, chain fwd, etc) so he may well be right about it in our case.

He also advises (less convincingly) against using primary winches to attach the drogue. The forces generated in a breaking wave strike are enormous – >10,000 lbs. Instead, he recommends attaching to custom “chain plates” built into the hull (topsides) at the transom end. Must confess, having just spent a bunch of time over the last couple of days pulling chainplates (think seized nuts on the capshroud chainplates, which resisted every penetrating lubricant I had, a blow torch and two impact drivers) the last thing I want to add to our boat is more chainplates!

September 25, 2010 at 07:33 #7531

Helene de Mer
Participant

Hi Van

A Good point!

Jan

September 26, 2010 at 17:25 #7541
michael bennett
michael bennett
Participant

Would agree, it is a good point, I would have thought fitting such chain plates a litte OTT, and would they be sufficient for the anticipated 10k pounds. Are such forces a maximum for a very short time frame anyway, I really dont know.
I have up forard a very heavy chain cleat mounted in front of my windlass, if, and its a big one, I ever get in the need of such drastic measures i would go aft from the cleat both port and starboard, around the winches ( brand new Holmatro and delighted with them )and put my faith in that. Remember we have boats that will look after us better than many others, one of the reasons i am an owner.

January 30, 2017 at 09:24 #26023
Richard Garlant
Richard Garlant
Participant

Hi Peter

I know it’s a long time since we started this discussion. Did you make the Jordan drouge? I’ve been reading about various types and have decided on one as well. What length did you settle on?

Richard

February 2, 2017 at 10:33 #26024
Jeff
Jeff
Participant

….”Instead, he recommends attaching to custom “chain plates” built into the hull (topsides) at the transom end.”

I remember discussing this with a couple of serious sailors 3 or 4 years ago. Their opinion was ‘get some st/steel chainplates made up & horizontally mounted on both aft corners of the hull with adequate backing plates.’
I agree. I wouldn’t trust any of my 45+ years old deck-fittings to take those kinds of loads, re-bedded or not, & not even the winches. They’re not designed for that.
There’s no doubt, a Jordan series drogue would be a great thing to have in really severe conditions. (£££s aside)
I’ve never sailed in conditions that would warrant the use of a drogue, but I remember looking at 100+ mph hurricane-force winds from the deck of an offshore oil platform 200 miles off Aberdeen. The crests were about 2 football stadiums apart, not breaking, & about 40-60 feet deep inbetween. Definitely ‘drogue conditions’!.

February 21, 2017 at 07:08 #26032
Van
Van
Participant

Hi Richard, I’ve almost finished our drogue. I used Jordan’s suggested dimensions for a boat the size of the Nic 38. Here are the key points.

1. Connected to the aft topsides with custom chain plates and backing plates.
2. Design strength about 12,000 lbs breaking strength, a once in a lifetime event. Normally the peak forces will be <10% of this value.
3. A bridle (Y), about 20′ long on each side, made of amsteel.
4. A leader, about 75′ long, made of amsteel.
5. A primary drogue section of 50 yd containing 50 cones, breaking strain 12,000 lbs.
6. A secondary drogue section of 50 yd containing 54 cones, breaking strain 6000 lbs.
7. A final length of chain a few feet long with a 10 lb weight at the end.

One advantage of chain plates vs using deck fittings or winches, is that the rode can have a thimble and eliminate chafe concerns. Anything going through chocks on deck will be subject to chafe.

I’ll write this up on our blog when I finish.

Hope this helps!

Van

February 21, 2017 at 08:58 #26033
Richard Garlant
Richard Garlant
Participant

Thanks Van

That’s great. I hope I never need to use one. I’ve fitted some very strong deck cleats aft but need to beef up the backing plate.

Thanks for your help

Richard

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