Loss of KELAERIN Rescue of Crew June 2018

[cyan]

Originally Posted by El Pinguino

No Most unlikely , because one is lefthanded, the other is right handed.... they are also very short low profile levers....

Ah yes, the left-handed and right-handed latches need to rotate in opposite directions to open. Oh, but, wait- the external handles can point TOWARD EACH OTHER when closed, parallel to the edge of the hatch with the dogs. To open, they BOTH need to rotate 90 deg toward the hinges. Maybe this is only when the outer handles are installed 90 deg wrong? (I've been on some funny boats)

A severe water flow from the dog side toward the hinge side would torque BOTH latches in the direction of opening, in this case. The only remaining question, is what is the torque needed to open, and can a serious horizontal green water flow provide such a torque. Even ONE latch torqued in the wrong direction could be trouble. More math?

[El Pinguino]

Originally Posted by cyan

Ah yes, the left-handed and right-handed latches need to rotate in opposite directions to open. Oh, but, wait- the external handles point TOWARD EACH OTHER when closed, parallel to the edge of the hatch with the dogs. To open, they BOTH need to rotate 90 deg toward the hinges, right?

A severe water flow from the dog side toward the hinge side would torque BOTH latches in the direction of opening. The only remaining question, is what is the torque needed to open, and can a serious horizontal green water flow provide such a torque. More math?

Foredeck hatch should have hinges forward.... green water from forward of the beam will be working to close the hatch.

Any midships hatch should have had the force of the water reduced as it removed the dinghy or the dodger or whatever...

Aft hatch in a CC like mine?... possibly should have hinges aft but mine is fitted hinges frd so as to take advantage of a bit of venturi effect at anchor... when somewhere warmish.... in fact all mine are hinges frd...

[mitiempo]

In my opinion a properly installed foredeck hatch on a boat venturing offshore should have a dam around the hatch. This prevents any water hitting the lip of the hatch with any force.

I believe Noelex's Bestevaer has these, Dashew's boats all do as well.

[cyan]

Originally Posted by El Pinguino

in fact all mine are hinges frd...

But then The Admiral requests the forward hatches to open forward because the tropics are, well, tropical...
Someone makes a reversible design. A&H maybe?

[a64pilot]

I'm not math guy, but I'm a little suspect of the math, just giving it the evil eye, it looks like maybe 2 square inches max, which if you apply 30 PSI to it, then you have 60 lbs of force.
I'm even way suspect of even 30 PSI, I don't think there is a boat that could withstand that. Think now, that's 10 times as much pressure as you put in a dinghy, and if you have ever actually measured a dinghy at 3 PSI, it's brick hard.

But, again I suck at math, but don't think forces are so easily explained.
30 PSI would tear everything off of the boat, and or tear the boat to pieces, and the math was much higher numbers wasn't it?

Now I suck at math, but a 40 ft long boat with 4 ft of freeboard has 160 SQ ft of surface area? 160 xx 144 to convert to square inches, times 30 for the pressure is 691,200 lbs of force on the side of a boat.
Does that sound likely to you?

[Jim Cate]

Originally Posted by mitiempo

In my opinion a properly installed foredeck hatch on a boat venturing offshore should have a dam around the hatch. This prevents any water hitting the lip of the hatch with any force.

I believe Noelex's Bestevaer has these, Dashew's boats all do as well.

Agreed for sure! The chap who built our boat made dams around all the hatches. They are simple timber framed hatches with some additional baffling in the lips and incorporating a simple foam strip as the ultimate seal. They have never leaked in the 15 years that we have owned Insatiable II. I trust them more than our Lewmar ports!

A good design IMO, one that does not rely upon brute strength of the dogs and hinges, for the damn deflects any direct flow elsewhere, protecting the vulnerable gap between hatch and deck.

Jim

[DumnMad]

Originally Posted by a64pilot

I'm even way suspect of even 30 PSI, I don't think there is a boat that could withstand that. Think now, that's 10 times as much pressure as you put in a dinghy, and if you have ever actually measured a dinghy at 3 PSI, it's brick hard.......
Does that sound likely to you?

30psi is the lower end for design hull pressure for steel ships. Breaking waves hitting a flat surface.
This is one reason running is a good storm tactic.

[cyan]

Originally Posted by a64pilot

I'm not math guy, but I'm a little suspect of the math, just giving it the evil eye, it looks like maybe 2 square inches max, which if you apply 30 PSI to it, then you have 60 lbs of force.

Well, if the gap is close to 5mm, then it's 0.2" high.
The Lewmar Ocean 70 is 24.5" wide where the flange rises vertically.
0.2 * 24.5 = 4.9 sq in

From my earlier equation using 20 kn, the pressure was 15.8 PSI
4.9 sq in * 15.8 PSI = 77 pounds of force.
Using 30 kn, the pressure was 35.6 PSI
4.9 sq in * 35.5 PSI = 174 pounds of force.
(these numbers are slightly different because I used 24" the first time)

It's interesting to note the V^2 term: Only 50% more water speed more than doubles the pressure. This seems to be the biggest factor. Imagine the effective water speed when a wave falls from 7 meters on top of you.

I'm not convinced that this happened on Kelarin, but if my hatches ever suffer a direct side-impact from such an event, I'll be wishing I had Jim Cate's hatch-protecting dams instead of the edge side of a Lewmar. A-rating or not.

[Snowpetrel]

Some pictures on Tiger lillys facebook page of the inside of kelearin. It is pretty ugly! Stove is half ripped off its mounts, debris all over the floor, etc.

https://m.facebook.com/story.php?sto...00003131247749

[mitiempo]

Originally Posted by Jim Cate

Agreed for sure! The chap who built our boat made dams around all the hatches. They are simple timber framed hatches with some additional baffling in the lips and incorporating a simple foam strip as the ultimate seal. They have never leaked in the 15 years that we have owned Insatiable II. I trust them more than our Lewmar ports!

A good design IMO, one that does not rely upon brute strength of the dogs and hinges, for the damn deflects any direct flow elsewhere, protecting the vulnerable gap between hatch and deck.

Jim

Google found this thread on hatch dams/breakwaters on this forum
http://www.cruisersforum.com/forums/...er-138844.html

[Eight Sails]

Originally Posted by a64pilot

30 PSI would tear everything off of the boat, and or tear the boat to pieces, and the math was much higher numbers wasn't it?

Someone noted that flat spray can knife aft as far as an unprotected cockpit with force similar to a power washer jet. I'm not sure of the math, myself, but note that a typical power washer develops from 1,300 to 2,000 psi at the nozzle. The way it does that is kind of like forcing green water into the slot between the lid and base of a hatch, come to think of it....

It's enough to damage the nonskid and drive water into deck core under poorly sealed fittings, but you see people doing it anyway. It would be an interesting, non-mathematical experiment to borrow your neighbor's power washer and try turning the hatch dogs.

Anyhow, I don't doubt that green water sweeping a deck exerts considerable prying force on the underside of an exposed hatch.

[Copacabana]

Originally Posted by cyan

But then The Admiral requests the forward hatches to open forward because the tropics are, well, tropical...
Someone makes a reversible design. A&H maybe?

I have all Goiot hatches on my boat (except one small Lewmar in the head) and after reading this thread, I'm suddenly delighted with them! They open forward or backward and are dogged down with 4 stout threaded metal latches, one in each corner. Also, they are built very strong out of aluminium (no plastic anywhere except the thick nylon hinge pins, which are not structural). I'm not sure Goiot makes them anymore, but if they do, I can highly recommend them. I also have a solid hardwood raised barrier around all the hatches to protect them from water coming across the deck. I have no doubt about the integrity of these hatches.

[bcoletti]

Originally Posted by belizesailor

In this case we have a well prepared and well found yacht with an experienced crew, no big glaring deficiencies here. So what to learn?

I think a few things (not second guessing or critisizing, just analyzing):

Avoidance. Its always better to avoid a bad situation, so how could they have potentially avoided this? They switched to more responsive ashore contacts which was good, but I think more active weather routing support from ashore might (might) have helped them avoid the weather bomb. Either a pro weather router or knowledgeable friend.

Storm Tactics. They found themselves in a trap running with the storm. Heaving-to or deploying drogue/sea anchor may have helped. This could have been a good situation for the Pardey's tactic of sea anchor assisted heaving-to. Heaving-to likely would have helped with the rescue too...pretty amazing that rescue swimmer could haul himself on to a boat doing 5 knots.

Below Decks. As already posted, better securing things below decks would have lessened the carnage.

Companion Way Closed. Probably good to have a policy aboard for when the companion way stays securely closed based on sea state/winds. Downflooding is a common mode of loss with monohulls (big & small).

Clipping In. Also good to have a similar policy for when to clip in even in the cockpit. The husband came very near to becoming an MOB...likely fatal under the circumstances.

The Life Raft Debate. There are many rescue accounts like this one where the life raft or dinghy were lost. This case is unusual in that both were swept from the decks. Redundancy is good I think, which is why I carry both, but in this case they needed a plan C. On longer crossings mine is below, but accessible, in a valise in a bunk, but thats on a cat where catastrophic (sudden) sinking is unlikely. On a mono, where catastrophic sinking is a possibility, I think its best above decks with a hydro relase. Theirs was well secured, so I dont know how to improve upon this in their case. Ideas?

Other thoughts?

Great post - thank you. Can you expand on the cat v mono point. With the same fact set what would be the most likely outcome if Kelaerin had been a similarly sized cruising cat?

[Eight Sails]

Originally Posted by Copacabana

I have all Goiot hatches on my boat (except one small Lewmar in the head) and after reading this thread, I'm suddenly delighted with them! .... I also have a solid hardwood raised barrier around all the hatches to protect them from water coming across the deck. I have no doubt about the integrity of these hatches.

To round out the exposition of hatch alternatives, here's Bill Siefert's recommendation: "The strongest deck hatches I have found are Bomar cast Almag 35 with extra ribs extending under the Lexan glazing (any transparent material used for windows). Bomar cast opening ports are also rugged" (Offshore Sailing, IMP, 2000, p. 176). Daniel Spurr writes: "Hatch frames are made of plastic (no good), extruded aluminum (most common), extruded stainless steel (heavy), and cast aluminum (best).... Major makers include Lewmar (www.Lewmar.com), Atkins & Hoyle (www.atkinshoyle.com), Bomar (Pompanette, LLC - Marine Hatches, Windows, Doors - Made in USA), and the French company Goiot [http://goiot-systems.com/en/hatches/]" (Spurr's Guide, 3d ed., IMP, 2006, p. 170).

[a64pilot]

Originally Posted by cyan

I'm not convinced that this happened on Kelarin, but if my hatches ever suffer a direct side-impact from such an event, I'll be wishing I had Jim Cate's hatch-protecting dams instead of the edge side of a Lewmar. A-rating or not.

Realize of course that "dams" are the responsibility of the boat manufacturer, not the hatch.
If you want them, they ought not be hard at all to add, even out of aluminum.
I'd be sure to have a drain in them though, at least two, but probably four, 1 near each corner