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Bute Thursday 8th August.

Updated: Apr 8, 2021

We were back at it bright and early on Thursday. It was hard to believe that we’d been doing this for best part of a week. In actual fact we’d been flat-out for over a year and that’s without the other countless years before and now it was Thursday and we still didn’t feel like we’d got ahead despite working all hours.

We’d lost a morning through a lack of fuel then we’d lost another through making a canopy. Wednesday went to plan but we still had issues. The idle remained defiantly high and now we knew that Bluebird would ‘scootch’ (one of Ted’s rather descriptive hydroplane words) along at 100mph on 50% throttle with little sign of slowing down so getting her off the plane required easing out of the throttle quite a way in advance and then it jumped the detent in the Boctube control at the slightest chance resulting in a flameout miles from home followed by a lengthy tow home.

Another persistent problem was the unrelenting water ingress and that was a real worry because it did it when standing still. We stood and watched as the transom slowly slipped into the water over a period of tens of minutes then one of us would climb up and hit the bilge pump switch only to see gallons of water sluicing out. There’s absolutely no question that had we left her afloat for any length of time she’d have filled and sunk. Our gauge was the small fairing that encloses the top of the rudder and the tiller arm. The ‘pie tin’ as we call it. It’s sealed so the water wasn’t getting in that way but with the hull pumped dry its underside lay about level with the water surface. Down she’d slowly go until the water began to lap over the top of it whereupon we’d fire up the bilge pump to raise it back up the inch or so it had descended.

Did we have an unseen rupture in the hull? What if we did and it suddenly became a big rupture at 100mph? That would be bad, but despite us going under there to inspect and run our hands over every millimetre all we could find was the billiard-table smooth underside with nothing untoward. Same with the sloping floor forward of the step at frame 19. There it sat with its dragon’s teeth looking and feeling solid as can be.

We considered the actual step and whether that could be leaking but way back when in the build we’d made sure it was bombproof by adding a laser cut bulkhead behind the aluminium skin because the design of the boat at that point was such that we couldn’t see a way that it wouldn’t leak and we weren’t having that!

Where the bloody hell was all this water getting in?

With no immediate answer, and at least it didn’t seem to be getting any worse, we at least continued our training mission and one thing we did want to master was refuelling with the boat afloat. Up to now we’d done a full recovery in order to top off the fuel tank but this involved massive manpower, much time and the obvious risk to life, limb and the precious machine. If we could get close alongside and work out a process to pump paraffin from a drum on the floating jetty it would tick a lot of boxes but if we inadvertently pumped a zillion gallons of fuel into the loch and killed the ospreys we’d be most unpopular so it needed thinking about.

Another issue with this plan was the moorings for the floating jetty. These were horrible, rust-crusted chains projecting outwards just under the water surface at fort-five degrees and they’d have made short work of any aluminium that grated against them so first thing was to station a diver in a drysuit at either end of the boat alongside the chains to act as a human fender to keep our priceless tinware off the rusty chains. That was fun job because the unseen bed of the loch only a few feet below was an obstacle course of concrete blocks and discarded tyres that made walking very difficult but divers are used to such hazards and it didn’t take long to get the hang of that. Next, we had to learn to string a spill boom all the way around the potential danger zone. If we did have a fuel spill we needed to know it would be swiftly slurped up by the long, white sausage that we floated on the surface to ring the area. We’d also discovered that by the deployment of this wonderful invention we could pump the bilges straight into the loch within the boom and any oil would be instantly plucked back out – it was a brilliant thing.

So, with our human fenders deployed and the spill boom in place the topside crew could clamber onto the main spar with the fuelling hose and carefully fill the tank. I say carefully because it would fill lazily for ages then suddenly go full to the brim with the overflowing fuel running straight down the outside of the main tank but very much inside the boat and straight into the bilges and that was a nuisance. Naturally, the instinctive thing to do in those circumstances was to pluck the fuelling hose out of the overflowing tank but it was less instinctive for the pump operator to cut the power at least until he saw his kerosene-covered colleague flapping about with juice streaming from the pipe. At that point we hoped the spill boom would pick up the slack and we’d mop up the rest with cloths but this was our first go and most of this inelegant ballet was still in the future because, having taken on the role of being the aft human fender I was standing chest deep in murky water when, during a brief lull in the hubbub, I heard the sound of running water coming from inside the hull alongside the jetpipe. I called for hush and had a proper listen and, yes, there it was again, a steady trickle as if from a half open tap and, intriguingly, the water was obviously entering quite high up and pouring down into the bilges.

Where on earth was that getting in?

We’d inspected all over the underside assuming the water was getting in from below but never thought to look higher up in case it was getting in up there and running down but a swift look about revealed nothing – and then the penny dropped.

The top of the rudder where it enters the hull and is affixed to the tiller arm is just about level with the water surface. There’s a seal at the bottom of the rudder shaft but it’s pressed into an aluminium block that had all but welded itself onto the bottom of the tube through which the rudder passes such that we were unable to dismantle it during the rebuild without major surgery so we elected to grease it and leave it alone. In fairness the impression was that water wouldn’t go high enough up the rudder shaft to get over the top anyway and even if it did it ought not be able to escape the pie tin and into the hull. Wrong on both counts...

Add in that it is probably circa 1956 anyway and, guess what, it had failed – unsurprisingly – so the water was simply filling the rudder tube then spilling over the top and into the hull and the more the hull settled the more water came in as the top of the tube was pushed beneath the surface. This, then, was the cause of our ingress. We ordered a swift recovery and got her up onto the slipway.

There then followed a strange happening. It took Barry From Grimsby – our chief of all things steering seeing as he’d personally rebuilt it from the ground up – no time at all to get the lid off the pie tin and the rudder out onto the floor so we could inspect the seal, which we knew was knackered.

BFG Works on the rudder

The rudder tube and pie tin were full of water so we’d captured our gremlin, we now needed a means to kill it or at least subdue it until we got back to HQ to put a proper fix on it.

Amongst our crew were two engine tech’s from a big aerospace company. Tom White (right) and Andy Hilton.

Between them there wasn’t much they didn’t know about our engine and fuel system but on the day in question their big, big boss had made the journey to see what we were all up to and before we knew it there he was, neck-deep in grease and muck sorting out our rudder! Jersey Mike produced a cartridge of bright blue grease and between them they packed the rudder tube until it would contain no more then inserted the rudder from beneath and forced it upwards with a trolley jack, blue grease escaping everywhere, until it would go no higher and every spare cubic millimetre was rammed with the good blue stuff. No way on earth was water going to get past that lot. Barry soon had the pie tin lid re-sealed and fastened down and so ended our water ingress problem. We put a permanent fix on that once we got back to base but more of that later. Next, we wanted to put a proper test on the water brake and were running out of Thursday.

Wanting to test the brake had nothing to do with slowing down, though we couldn’t deny that it might prove useful should some emergency arise. No, testing the brake was to see if it actually worked. If its retarding effect measured up to what Lew had in mind for it all those years ago so the next run was planned to feel it out and Ted was to be our test pilot.

Now then, many years earlier when we dived most summer nights in the North Sea from what is now our little grey support RiB, underwater visibility was often a limiting factor. Most nights you could just look down the anchor rope and see it stretching away into the depths because, contrary to popular belief, the North Sea is often as clear as any other sea but sometimes it wasn’t. When in doubt we had a bright yellow towfish for our magnetometer that we’d lower over the side until it disappeared from view then haul back up hand over hand counting off how many metres of ‘vis’ we had. But on a really murky day when the towfish vanished almost immediately what we’d do is dangle a leg over the side to see if we could see our foot on the end. If you could see your foot you had a hundred ‘centisocks’ if you could only see to your knee you had fifty centisocks and we’d likely go fishing instead but the point being is that centisocks became a deadly serious part of our lexicon over which we’d argue endlessly – then go fishing.

It therefore came as no surprise to find ourselves on the side of Loch Fad grouped around the cockpit discussing bananas.

Because of our accumulator woes we had only pump pressure to move our brake so at least we knew it wasn’t going to spear instantly into the water and destroy itself or plunge Ted straight to the bottom and having now gained a little first-hand experience of how the boat handled this was a scenario we were anxious to avoid so the failed accumulator was suddenly a blessing and as well as that we now realised we could add an extra layer of gentle brake deployment by being able to inch it down. We knew it took three seconds to fully deploy on the pump and this is where the bananas came in because, Stew, being of a military persuasion, was used to counting seconds in bananas. That’s what they do in the RAF – one banana, two bananas, three bananas and so on.

We discussed our bananas back and forth then settled on two but first we decided on a static test for two reasons.

At the previous day’s debrief, Ted had described the engine as lagging a little and the JPT had touched on 720 – very much its upper limit – then he’d described the boat as ‘not wanting to accelerate’ so we thought a swift static test might be in order and as I had most experience of engine handling on the rig and in the boat and knew exactly how it should feel I hopped in. For these static starts we just pulled and hauled the start boat out of the water and plonked it on the beach alongside.

With everything connected up, Malcolm made the surrounding area safe then I gave the engine a dry crank then opened the HP, switched on the igniters and hit the go button – nothing!

This was just exactly what we needed and, as ever in these situations, we put the blanks back in then held a quick post mortem around the cockpit.

It was gone four in the afternoon by now, we’d achieved precisely nothing and now we had yet another blown igniter fuse, which, as usual, we put down to water ingress. So the crew blew everything dry with an air line then swapped it out.

Second time lucky, we heat-soaked the igniters by leaving them running for a while because we knew this would be a hot start and with all that spare kero flushing abut in there we didn’t want to foul them. Bluebird uses an early ignition system that’s very easy to foul up with soot or liquid fuel and we once had to remove the igniter plugs in situ to clean them and that was a nightmare so a good heat-soak had become the order of the day if we had any doubts.

We had the expected hot start but otherwise we got it the second time, warmed the engine through then shut down. We were ready to go.

Well, almost. There remained one small task to complete first. Take a look at the pic below and you’ll see above and slightly to the left of the air hose plugged into the side a small alloy tank with a tall neck and two black, rubber hoses entering on its left-hand side.

On the Orpheus engine there are two drains to dump excess fuel offboard. One is on the CCU – the engine’s fuel injection system – to get rid of a small quantity, perhaps a teacup full, from the wrong side of a piston where it gradually accumulates when the engine is running and then is dumped on the next start to give the piston its full travel once more.

The other drain is on the combustion chamber from which unburned fuel from the engine spooling down on shut-down is dumped in much greater quantities when a spring loaded valve pops open as the combustion pressure falls away thus ejecting the fuel straight out of the underside of your aircraft and onto the tarmac. Not a lot of use on a boat as it would just swill about the bilges being a nuisance so what they did in 66 was arrange a pair of catch tanks down low in the hull, one on each side at the back, and redirect the engine drains to these. That worked but the solution to emptying the inaccessible catch tanks wasn’t very environmentally friendly because all that happened was that on the next start-up jetpipe static pressure was used to pressurise the tanks and throw the whole lot into the lake!

This would have caused much upset and undoubtedly led to dead ospreys so we disconnected the outfalls and re-routed them to our tank on the side of the engine then we put a breather in the lid with a fine paper-element filter so there was no chance of ejecting a kerosene mist into the engine compartment.

We originally made that tank so we could keep a supply of oil running through the hyd pump when running an engine on the test rig because removing it is torture and a new gasket has to be made each time. We later modified it to double as a catch tank for the fuel drains. It was tried, tested and it worked – until we had a hot start.

A hot start filled it to the brim so it had to be emptied and the filter cleaned before we could run again so that had to be done before we could launch with Ted aboard. At least we had our launching down.

The wind was fighting us this time. It wasn’t strong but it was swirling around at our end of the loch making it impossible to hold the boat on the correct heading to get a clean release but we spoke with Ted, Malcolm and the safety crew and decided it was still safe to proceed.

We slipped into our various roles, made the countdown and watched the heat-haze swell from behind the boat as she began to move forward and the start boat was disconnected. And then, as quickly as the engine had lit it died again leaving Ted marooned in the middle of the loch.

What this time!

We went over to see what had gone wrong. It hadn’t sounded bad or expensive but we didn’t throw away a run without good reason so it had to be serious. In the event it was a slightly embarrassing case of pilot error. Ted had somehow missed opening the LP cock from his checklist so the engine had lit normally but with the valve closed between it and the fuel tank it vacuumed the hoses and starved to death in mere seconds. It was a test we’d planned to conduct anyway as a counter to a runaway throttle – just not today.

We towed him back, reconnected the air and had another go and this time he was away, though the wind necessitated some manoeuvring to get back on track.

The fin had rapidly turned her once disconnected from the start boat and with no steering authority until at least some forward speed had been gained there was a bit of work to do in the cockpit before Ted could floor it. And floor it he did and at last we had a run going on.

The lumpy water also added to the natural pitch oscillation that the boat exhibits as she climbs out. The planing angles, according to modern hydrodynamic thinking, are a little steep so as the boat unsticks she is thrown upwards only to come back down and dip the step at frame 19 back into the water due to the forward CofG. The resulting clouds of spray were spectacular sometimes but, needless to say, the pilot’s visibility was reduced to nothing. But soon she was up and tearing over the water and already up to the top end of the loch, passing the safety boat as she went.

This was much more like it. We assumed the planned test of the water brake had been carried out – in that direction so that should anything go wrong, Ted had a nice squishy reed bed up there for a soft landing and some equally squishy cows rather than a stone causeway and old Mrs. Miggins to crash into.

Then came silence followed by much radio traffic and Jimmy’s work boat heading down that way and next time we saw our charge she was being towed back yet again and towing was a least-favourite occupation of all the boat crews because K7 under tow is like an untrained dog on a lead.

Ran out of fuel, was the first information that came back but that was quickly corrected to the dreaded Bloctube detent gremlin. It had once again caught Ted out and now it was getting personal. The water brake test had gone well, at least. The debrief notes read…

Tested brake – foot off → scooch.

Settled relatively well – brake 2 bananas down.

2 seconds later, decay. Front went in heavily and plume of spray spat up.

Foot on throttle – sped up a little but didn’t go. Lazy.

Foot on throttle again but didn’t want to rev.

Boat recovered to shore.

Part of the problem was the sheer volume of water that had gone through the engine giving it a very impressive compressor wash but yet again the HP cock was found to be in the off position.

We gave the engine a good inspection because if you put enough water into one of these things, and that doesn’t include the worst rain you can imagine and then some, we’re talking solid water here, instead of the blades pushing the denser medium backwards it pulls the blades forwards, bending them, so we wanted a good look before we attempted another start. Thankfully, all looked well and the engine was spotless inside too (though we did later find water in the air side of the fuel control system where it should never have been able to get to so we’ll need moisture traps in there before we run next time) so we came alongside, pumped in 20 gallons of premium paraffin then lined Ted up for another go, this time with the intention of finding a way past the engine shutting down problem.

We had enough daylight and conditions were still just about useable so we were also learning about operating with a little wind and chop on the water. This, we hoped would be a good one and then we noticed something.

Have a look at this old photo of Clive Glynn, one of the 66/67 team, pointing out the damage done by a seagull striking the main spar root fairing – or rather the fairing striking the seagull. But look immediately below his head and there’s another dent in the spar fairing itself, much softer damage but clearly a dent. This was a result of the water brake being applied and a jet of high-pressure water being forced up the inside face of the sponson and crashing into the lower, leading edge of the spar fairing.

We returned from the test of the water brake and guess what…

Spooky or what. A virtually identical effect. We used a stronger grade of material than the original just because we could which perhaps answers why it’s a little more localised but there it is all the same.

The fairing is purely aerodynamic and not structural so it can be left that way as another crumb of resurrected history but it also demonstrates that once you stray away from the tough underside where all the work is done the upperworks are somewhat prone to cosmetic damage.

We soon had Ted underway…

He now had it worked out just how get the boat settled then nail the throttle at the crucial moment such that she would leap up and away despite not having full throttle available. This letting loose with the throttle and Ted acclimatising to the cockpit workload was beginning to reveal that the engine was only achieving about 90% rpm, which was leaving an appreciable amount of thrust on the table. We would later discover this was due to our efforts to cure the high idle with linkage adjustments and we’d robbed ourselves but it didn’t seem to matter much – imagine what she’ll go like next time!

The good old Keane’s Cottage money shot again, this time with a little splash of evening sunshine and then, whoosh – she fired through the narrows straight as you like and out of sight.

This was usually the point when the radios all crackled into life and one boat or another would potter away up the loch to begin the frustrating mile and a half tow back to base but this time was different. The breeze brought us tantalising hints of engine noise, waxing and waning but still there and then, no mistaking it, the Orph’ was spooling up again and it sounded different – the sound of it hungrily ingesting air rather than exhausting through a cloud of steam. It was a different sound, an angry, metallic howl that grew and grew until…

It was an astonishing sight!

Ted shot past then came out of the throttle. No need for the water brake as Bluebird slowed naturally then dropped back in and came to a standstill opposite the slipway. Ted stood up and did a little victory dance for the spectators.

Here’s a video of that run.

Ted had held onto the HP cock this time and kept the engine lit to make the turn then come back. At the debrief it was reported that the idle had returned to normal making the turn easier and we wondered whether the new fuel had somehow made a difference. All also agreed that we had found the wind limits for running K7. Not because it was dangerous but because we all had issues handling our boats and Ted’s low speed steering, especially with that big, useless fin up top, was poor on a good day. But this was exactly the sort of thing we had come here to learn so it was all priceless data.

With 173kph recorded for the outward run and 220kph on the way back (that’s 107 and 136mph, by the way) with no gremlins in the system and all crews on-point throughout, not to mention putting on a great show, we finally felt we were getting ahead of the game. Tomorrow we would get Stew in there and see if he could do the same. The beer bar was calling…

As a small postscript to this – when we returned to HQ and started our strip inspection one job high on the list was to permanently sort the rudder water problem. One option was to get the original seal out of its aluminium holder but that would have meant destroying it so instead a very brave man set the rudder up in a lathe…

Then he machined a groove in it and we installed a quad ring.

It was all calculated to a nicety so now there’s no way water can get up and over the top, all the original parts are still original and you can’t see the repair. At the same time, in order to calculate the radius at the base of the groove because we don’t want the rudder to snap at the groove, we had the material analysed and discovered that it’s a high quality tool steel. Ken wasn’t one for skimping.

Til next time.

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