How seaworthy is a Sea King?

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Chris Partridge Chris Partridge
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How seaworthy is a Sea King?

I have just watched George Clarke's Amazing Spaces (always fun) featuring a Sea King helicopter converted into a holiday hut.
Of course, I started fantasizing about converting one into a motor yacht. Put a largish outboard into the tail fin so the prop dangles down behind the hull and Robert's your relative.
The big question is...how seaworthy is a Sea King? I know we have at least one Westland engineer here. Apparently, you can get a stripped-out, totally grounded Sea King for about ten grand so it could be a relatively cheap and very stylish home-built-boat.
alopenboat alopenboat
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Re: How seaworthy is a Sea King?

> The big question is...how seaworthy is a Sea King? I know we have at least
> one Westland engineer here.

In flying trim a Sea King has all the stability of a telephone box. This
is why the undercarriage is fitted with buoyancy bags (Aircraft for the
navy have wheels, the army use skids). They are very stable upside-down.

If you took off the engine, gearbox and rotors you would lower the cg
dramatically. The lower fuselage  (known as the bath tub) is waterproof,
so it should now float OK.

But now you haven't got much of the original left.

And what you do have would be pretty uncomfortable.





Jeremy Jeremy
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Re: How seaworthy is a Sea King?

I've ditched in one, a sister to the one on the George Clarke programme, pennant number 595 according to my logbook, on 17th May 1985 in Falmouth Bay.  We had a main rotor gearbox total lubrication failure (pipe came off and all the oil pumped out).  We managed a controlled landing on water, which was untypically calm for Falmouth Bay, and slowed the rotors without using the rotor brake, which helped to stop us turning over.  

I was the only bloke in the back, so while the two guys up front were shutting things down, I slid the cargo door open and chucked out the MS10 dinghy, so we didn't each have to use our PSP dingies.  Despite the calm, and all the flot bags inflating properly, it was incredibly unstable, and we thought it would turn turtle any moment.  I held the MS10 against the lip of the cargo door and we had a silly argument as to who was getting into the dinghy first.

As I had a hold of it it seemed sensible for the other two to get in first, but the pilot (who on this occasion, rather unusually for an ASW Seaking, was the captain of the A/C),  insisted on getting in last, which meant me letting go of the dinghy and as I got in, with him jumping into it (he was the only one of us who got wet, and he didn't need to).

We drifted well away from the bobbing A/C and were picked up in minutes by a Wessex SAR helo - he'd got airborne on hearing our Mayday and did a very good job of getting to us very quickly.  All three of us hi-lined up to the Wessex, to the disappointment of the SAR diver, who didn't need to jump in and do any heroics.  It's an odd entry in my log book, as I took off from Culdrose in one type and landed back in another!

The A/C stayed upright for an hour or so that it too a PAS boat to come out from Falmouth and secure the A/C alongside.  Some engineers climbed over and up and folded the rotor blades back  and with the A/C lashed to the side of the PAS boat with a load of big fenders for added floatation she was towed very, very slowly back to Falmouth, where she was craned out and sent to Fleetlands to be rebuilt.  At that time she was an HAS Mk2, but when she came out of Fleetlands she had been converted to a HAS Mk5.  By  strange coincidence I found myself flying in her again the following year.  Her pennant number had changed, but the tail number was the same, so I only noticed it was the same airframe when I came to fill my log book in later.

The simple answer to the question is that with the engines off and the rotors freewheeling on the sprag clutches, as would be the case in an emergency water landing, 9 times out of 10 a Seaking will turn over very quickly, especially if the flot bags are on auto, as they often operate asymmetrically.    With the engines running it's perfectly OK to make a controlled water landing, in fact the US coastguard used to use this technique, recovering casualties via the cargo door and a ramp, rather than do as we do and winch people up, either solo with a hi-line (if they know what they are doing) or with a harness and strop and crewman on the wire.

Personally I'm quite fond of the Seaking.  Looking through my log I flew around 800 hours in various HAS Mks (and one flight in a Jungly, for some reason).  it's a damned tough helo, that's built like a brick outhouse in comparison with a lot of newer stuff.
Paul (admin) Paul (admin)
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Re: How seaworthy is a Sea King?

A friend at work used to be a SeaKing pilot in the Navy. Standard training is to strap the crew into a SeaKing body shell, then flip it over and drop it into a test pool. So in low light with spatial disorientation you have to unbuckle and escape through the water rushing into the cabin.

-Paul
Say NO to Brexit. Kick it into the long grass
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Re: How seaworthy is a Sea King?


> A friend at work used to be a SeaKing pilot in the Navy. Standard training
> is
> to strap the crew into a SeaKing body shell, then flip it over and drop it
> into a test pool. So in low light with spatial disorientation you have to
> unbuckle and escape through the water rushing into the cabin.
>

Not just pilots. It was interesting, but the water was cold.



Jeremy Jeremy
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Re: How seaworthy is a Sea King?

No, we all had to undergo the dunker every 2 years.  For me that meant 11 dunker sessions over my career, with each one being four immersions in the pool.

The procedure changed a little over the years, but essentially you were strapped in to a mock-up A/C, dropped into a pool of water (or later, when the dunker was built at Yeovilton and the one at HMS Vernon closed, lowered into the water).  

The later drills consisted of a first drop with the A/C staying up right, so all you had to do was wait for motion to cease, unstrap and swim out your designated escape hatch/window.  The following drops were with the rotation system enabled, so the thing turned turtle.  The drill was the same, hold your breath as the water reaches your nose, wait for motion to cease, then unstrap and escape.  The final run was to do it with all the lights turned off, so you were in total darkness and had to escape by feel.

After I stopped flying rotary wing (so avoided the need for dunker sessions) they introduced an emergency air system, that gave you an extra breath or two if you got stuck in the upside down cabin.  Personally I wasn't 100% convinced that it was a great benefit, as it gave you maybe an extra 30 seconds or so to get out.

The one positive aspect of a dunker session was that it flushed your sinuses out exceedingly well.  It felt as if someone had given them a rodding out with a chlorine-soaked sponge afterwards..............
Chris Partridge Chris Partridge
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Re: How seaworthy is a Sea King?

Very interesting and a bit frightening.
Purely out of theoretical interest (I must emphasise I have NO intention of blowing ten grand on a scrapped Sea King just to convert it into a dodgy if stylish power boat) what if the airframe was stripped of everything including the engine and the tail? The tail would be useless and SO expensive when mooring at the Folly Inn. The undercarriage would go too.
Presumably the hull would have to be filled with ballast to bring her back down to her lines and this would make her more stable. Put a 300hp outboard in each sponson where the wheels used to go and there you are...whizzing over the Solent to universal admiration and curiosity...
inwe inwe
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Re: How seaworthy is a Sea King?

All this is all well and good but would it then get through the locks on the Thames for the raid?

Richard
Chris Partridge Chris Partridge
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Re: How seaworthy is a Sea King?

I think a bigger problem would be getting under some of the bridges. Anyway it would be a stupid idea. For the Thames, this:
Timmo Timmo
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Re: How seaworthy is a Sea King?

Can't help feeling that if converting a Sea King were possible Ratcatcher John would have already done it! Specially if you could get two very big outboards on it.

Tim.


On 31 Oct 2016, at 09:46, Chris Partridge [via UK HBBR Forum] <[hidden email]> wrote:

I think a bigger problem would be getting under some of the bridges. Anyway it would be a stupid idea. For the Thames, this:



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Jeremy Jeremy
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Re: How seaworthy is a Sea King?

In reply to this post by Chris Partridge
UK built (i.e. Westland, rather than Sikorsky) Seakings were never as well-sealed in the boat hull section as US Sikorsky built S61s, so would be a poor choice for a hull.  They were all "wet assembled" (i.e. sealant was applied to the mating surfaces of all the riveted joints), but we fitted some avionics stuff and wiring down in the boat hull, in the free space around the fuel tanks that also live down there (they are bag tanks, IIRC, so only need compartments) and never seemed to be very watertight.

As a result, UK built Seakings were never approved for non-emergency water landings, although this was an emergency procedure for some problems.  Stability for a water landing needed some lift and control, so it was normally a single engine failure "get out of jail" card.  IIRC, the procedure for a single engine failure where gross weight was over the single engine limit at that particular airspeed (hence the lack of translational lift) was to put down on the water with the good engine at near 100% torque to maintain control, then jettison all weapons in safe mode, dump some fuel if need be, chuck out anything not needed via the cargo door, then attempt a single engine rolling take off from the water.

Frankly I have my doubts as to whether it would ever have worked, but I'm pretty sure that was what was on the flip cards for the HAS Mk2 (I probably still have set in the loft, next time I'm up there I'll check).

The most common problems in my experience weren't engine-related, they were MRGB lubrication system related or sometimes the tail rotor intermediate gearbox.  Gearboxes always seemed to give more trouble than engines, but then they were pretty complex things taking pretty high loads.  The MRGB output shaft has the near static 10 tonnes of helo hanging from it, plus all the tranlsational loads from manoeuvring, so was a pretty heavily stressed bit of kit.
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