'Nobody in their right mind would build a naval base here today': Navigating in and out of Devonport
- Reference: 1632480548
- News link: https://www.theregister.co.uk/2021/09/24/hms_severn_plymouth_navigation_course/
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Entering and leaving Plymouth, home to Devonport naval base, is a tricky operation under naval rules as we observed.
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Plymouth, Devon, England, UK: Devonport naval dockyard in the Hamoaze Estuary
"Nobody in their right mind would build a naval base here today," quipped one officer. The entrance to Devonport consists of a long and winding route to follow the marked deep water channel. Although Severn isn't the largest of ships in the fleet by a long way, she still followed every twist and turn of the channel on the way up.
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HMS Severn (click to enlarge) Pic copyright: Helen Harper
Each student navigated the ship along one precisely-planned leg, either entering the port or leaving it; as a training ship, Severn does this several times a day. Precision is the order of the day: whereas a civilian sailor might bring their ship into port by glancing at navigation buoys and steering as required so they don't bump into anything, the Royal Navy plans every single turn and straight leg and speed with military precision.
[3]
An old friend of The Register passed Severn as she left Portsmouth: HMS Enterprise, which hosted the [4]original Boatnotes series from the Arctic Circle (click to enlarge)
[5]Navigating without GPS is one thing – so let's jam it and see what happens to our warship
[6]We're all at sea: Navigation Royal Navy style – with plenty of IT but no GPS
[7]What happens when a Royal Navy warship sees a NATO task force headed straight for it? A crash course in Morse
[8]Big data at sea: How the Royal Navy charts the world's oceans
"It's about building the skillset," one of the FNO course instructors told your correspondent. "Yes, we as the Navy do this [entering and leaving Plymouth] countless times during our careers but planning the pilotage means that when we're entering a new port, the skills are there to get it precisely right first time."
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The quartermaster's position on the bridge, where the ship is driven from. Note the two levers for the main propulsion, the bow thruster lever - and the steering wheel! (click to enlarge) Pic: Gareth Corfield
During one practice run into Devonport naval base at night we got a flavour of just how much precision the Navy demands.
"Wheelover… port 10," said the trainee navigator from his post at the pelorus, the main gyro-compass in the centre of the bridge.
[10]
A police launch cleared HMS Severn's path of civilian sailors, including this pretty little sailing vessel. Note the outboard motor (click to enlarge) Pic: Gareth Corfield
Wheelover is the point on a navigation leg where, as the name suggests, the crew must start turning the wheel to intercept their next leg. Some maths based on ship's speed, rudder angle ( Severn 's twin rudders can swing up to 35˚ in either direction) and tidal flow tells you where the wheelover point ought to be.
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The view from HMS Severn's bridge as she entered Plymouth harbour (click to enlarge)
"10 port on, sir," said the quartermaster, on the ship's wheel.
"On track visually. Midships. Steer 328. That's seven cables to the anchorage," continued the student navigator.
Outside the bridge windows, dark land masses loomed ever larger. Outside on the bridge wing, a crew member called in a bearing from a nearby navigation light.
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"On track visually," repeated the student. "With three cables to run, expected depth 28.5 metres-"
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"Depth 29 metres!" interjected a bridge crew member, keeping a steady eye on the ship's echo-sounder.
"Roger," replied the student.
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WECDIS plot of the NATO task force during a [16]2018 trip to the Arctic in the HMS Enterprise (click to enlarge
Another navigational technique for fixing your position is comparing your height above the seabed with what the chart says. Just like in hillwalking, if you're passing over a recognisable lump or bump from the chart that gives you another clue about where you are. Combining that with bearings from landmarks above water can be a useful cross-reference.
While the student nav is keeping the ship on track, another student is monitoring the radar. These being British coastal waters there's always a number of pleasure craft and kayakers around. On a daylight run into Plymouth Severn was preceded by a police launch, shooing civilian sailors and paddleboarders out of the warship's path. A less precise operation than the one going on inside the bridge, but necessary all the same. ®
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[1] https://regmedia.co.uk/2021/09/22/shutterstock_devonport.jpg
[2] https://regmedia.co.uk/2021/09/21/hms_severn_b.jpg
[3] https://regmedia.co.uk/2021/09/23/hms_enterprise_passing.jpg
[4] https://www.theregister.com/2019/01/02/hms_enterprise_embed_life_at_sea/
[5] https://www.theregister.com/2021/09/22/hms_severn_gps_navigation_training/
[6] https://www.theregister.com/2021/09/21/hms_severn_fleet_navigating_officers_course/
[7] https://www.theregister.com/2019/01/02/hms_enterprise_embed_life_at_sea/
[8] https://www.theregister.com/2018/11/21/hms_enterprise_royal_navy_survey_ship_role/
[9] https://regmedia.co.uk/2021/09/23/hms_severn_qm_position_bridge.jpg
[10] https://regmedia.co.uk/2021/09/23/sailing_boat_near_plymouth.jpg
[11] https://regmedia.co.uk/2021/09/23/severn_entering_plymouth.jpg
[12] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_onprem/networks&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=2&c=2YU32OzXq9pcSJ7eQmh0mOwAAARQ&t=ct%3Dns%26unitnum%3D2%26raptor%3Dcondor%26pos%3Dtop%26test%3D0
[13] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_onprem/networks&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=4&c=44YU32OzXq9pcSJ7eQmh0mOwAAARQ&t=ct%3Dns%26unitnum%3D4%26raptor%3Dfalcon%26pos%3Dmid%26test%3D0
[14] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_onprem/networks&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=3&c=33YU32OzXq9pcSJ7eQmh0mOwAAARQ&t=ct%3Dns%26unitnum%3D3%26raptor%3Deagle%26pos%3Dmid%26test%3D0
[15] https://regmedia.co.uk/2018/12/21/nato_task_force_wecdis.jpg
[16] https://www.theregister.com/2019/01/02/hms_enterprise_embed_life_at_sea/
[17] https://whitepapers.theregister.com/
A straight run into a dock leaves it exposed to wind and waves when conditions are bad, as well as making it easier for an attacker. So ports generally don't have a straight approach but involve at least one turn on the way in and out.
The Register has taken a closer look at the precision demanded of naval officers conning their ships in and out of one of the most cramped ports where the Navy routinely operates.
Well, the Royal Navy only has three ports these days (and one is mostly used by submarines)
Nice picture of Southdown
everyone sees the Frigging Frigate maintenance sheds but Southdown - down river and on the Cornwall side is really nice. Couldn't spot my boat there though.
I've often wondered if the deep water channel wouldn't we a bit wider and deeper if there wasn't that ridiculous breakwater which must contribute to silting. I suppose it made sense from a defensive point of view when it was built 200+ years ago, but it must have a severe impact on currents. But of course in the early nineteenth century you weren't dealing with big ships.
It's the twists and turns around Drake's Island are the problem. There's an underwater ridge between it and the Cornish shore so ships coming out of the dockyard have to left hand down a lot to pass in front of the Hoe and then right hand down to avoid running into the Lido. Removing the ridge has been investigated, but all the modelling results in Sutton harbour silting up along with the entrances to the various dockyard basins.
Long time ago I saw the proper Ark Royal setting out through there. It had to leave the dockyard empty and do a first replenishment in the Sound, and could also only enter or leave on certain high tides when there was all of a foot (I did mention it was a long time ago) clearance under the keel.
Back in the late 1960s HMS Ark Royal was approaching Plymouth and just past Drake's Island she hit an underwater obstruction, only a minor ding - it was later revealed that the obstruction was a large rock which had been drilled by fleet clearance divers but for some reason (economics?) had not been blasted into oblivion
Depends if you think the French or Spanish are going to attack you
Difficult navigation, high batteries on each side above the entrance of the sound, the breakwater and other islands to build other forts on, loads of potential wharfage, the choke point between Devil's Point and Cremyll... looks bloody ideal.
Having navigated the twists and turns in and out of both Plymouth and Portsmouth, it was educational entering the US base at Mayport which basically involved stopping once you were alongside the jetty. I think the navs had had us lined up for about the last 50nm!