Navigation to a Moving Ship

[C of G]

I was fortunate enough to work with a pilot who once showed me how to navigate to a moving ship, but my filing system is sorely lacking and I am now hoping someone out there could post the formula used or point me in the right direction. No pun intended. Thanks...................

[Droopystop]

I am sure an ex pinger will give you the full answer, but apparently it is easily done using the circular slide rule. You put the wind on in the normal way and then add the (reciprical?) heading and speed of the ship on the end of the wind line and then go through the motions of determining the heading. You just have to hope that the ship maintains course and speed!

[steve_oc]

Of course if the ship in question is grey with guns on, you immediately assume it will be 180 degrees in the other direction from where it said it would be!

[SASless]

Carry lots of fuel.....and for one thing certain....the ship will never...never...never...never be where they say they will be.

With GPS on both ship and helicopter....things are a bit easier nowadays but the old scheme plotting the proposed track and hitting the trail like a hunting dog seemed to work (exept for the gray funnel line) where consulting a psychic would be more effective.

[Gomer Pylot]

I always just figured the offset in my head. Ships move very slowly compared to helicopters, so you can head nearly to its present position, with an offset of a couple of miles or so. If you get within 5 miles you can see it easily. I'm used to being told a rig, or ship, is in a block, which is comprised of 9 square nautical miles, and no more precise information. If I head for the center of the block, I know I can find the rig. It's hard to hide a large ship or drilling rig on the ocean.

SASless is right, they're never where they say they are. I've received coordinates that were a degree off, and it's much easier to hide a ship when you have that large an area, and especially if it's dark.

[WSPS]

Get the ship's position, punch it into the GPS, head for the ship.
As you said, a ship is bloody difficult to hide. Especially in the Arctic. You can see the beast from miles away (on a good day :E ).
With scientists, they usually quite accurate in telling you where they are :mad:
I never try to think about a combination of lost comms & bad w/x though...:=
or "poor GPS coverage" for that matter!

[[email protected]]

C of G, I do have a written explanation but it only applies to a circular slide rule (whizz-wheel), if you've got one, let me know and I will post the procedure.

[C of G]

Crab,

That sounds like it might be along the lines of what I had been shown before, and I still have my (dusty) whiz wheel, but I remember that I did the wind correction in the US way (wind up) rather than wind down. In any event, I do fully recognize this as an exercise and I do routinely make my way to vessels via GPS, VMC, and although I don't have a plan to do it, the SAR wicnchman/navigator who initially showed me, said it worked for him IMC within a very reasonable distance. Thanks................I would appreciate a look at it.

[eagle 86]

Used to work for me this way if departing a ship to return to that ship:
Plot point of departure with chinagraph on windscreen - plot to scale your track - plot to same scale ship track - when ready to return apply wind vector to your position - plot track from end of wind vector to ship's new position - assess bearing/distance and head home. Used to out navigate most baby "lookers".
GAGS
E86
PS Scratched windscreens use to hack off the ginger beers!

[rotorboy]

How to navigate to a moving ship:

Call ship on radio

Navigator see's you on radar.

Navigator gives you heading to boat.

Pilot see's boat from ways off, as there is nothing in the middle of the ocean for 100's of miles.

Pilot steers to boat, thats where food is.


Well thats how it worked on the tuna boat years ago.

RB:ok:

[helopat]

Of course if the ship in question is grey with guns on, you immediately assume it will be 180 degrees in the other direction from where it said it would be!

Hey, that was what I was going to say...took the words right out of my mouth.

HP

[Updraught]

A combination of GPS, DR and of course, RADAR has always proven successful.:) :confused:

[topendtorque]

Finding ships, hmmmm

I wonder how that compares with finding several hundred if not a couple of thousand cattle on a fifteen to twenty minute rotation in thick timber, or prolific canegrass, under the thicker timber, no radar, no lights and could all be in diametric opposition.
Especially if a tourist bus pulls up right in front of them with flash camers, flasher hats and shirts etc.

yessir must try these ships one day.

[Farupthere]

Create moving marker in the moving map system.
Transfer data to the NMS.
Press "exec" and let the computer play with the AP.
If a radio call is possible, correct datas and use DF.

[spinwing]

Well .....

What we (?) used to do was contact the ship or their handlers and get a probable position for the rondevous ETA ...... put that into the GPS (used to be DECCA ??? remember that stuff! :uhoh:) ...... then as we got to within say 20 Nmls made a radio call to the ship to organise the landing or winching clearance and then ask the radio op to transmit on 400Khz to get a bearing to the ship using the ADF equipment .... if necessary lock the key down to transmit continuously till the ship was in sight.

Worked brilliantly ....... most times . ;)

cheers :ok:

[Geoffersincornwall]

Picture the scene.......... Ops Room 3 on Ark Royal 1970...western Atlantic Ocean ..... Ops 3 delivering task for the day........

"so we want you chaps to bugger off in your smart new Sea Kings and look out there for those nasty submariney things... take your time... in fact we want you to come back in four hours ....... we will be ......here (points to 'x' on chart).... in response to dark frowns from the lookers he says "honest, we will honest.... we will be right there, the skipper has promised. Oh and by the way it's radio silence the whole time .... unless you get down to emergency fuel.. then you can call for help."

Four hours after take off - "F:mad: ing hells bells, we are are right where the ship said she would be and not a bl:mad: y sign of her, what do you estimate the vis up front"

"'bout 25 miles'

"Oh sh****t, what do we do now?"

"The SOPs say an expanding square search until we get to min fuel"

"Right then"

15 mins later we saw smoke on the horizon and there she was. We landed with min fuel in the tanks and a basket full of ideas on what we were going to do with Ops 3 when we got back. Never never never trust a fishhead (seaman type) when he makes that kind of promise.

G

:ok:

[Spunk]

It's good to hear that the above storries do not only happen to me. I was once asked to fly some sailors out to a ship "@ 30 miles off the Danish coastline". Finally, we almost ended up in Norwegian territory. Had to tell the crew to give me a ride for a couple of miles back to Denmark as there wasn't enough fuel left to fly home the entire distance. :\

[SASless]

Up D....

Nice thought but fraught with peril.....short cockpit discussion....North Sea...fugly weather....Decca decided to run amuck due to the snow fall....when asked....ok....now what? Me being the brains of the outfit...scary thought in itself....No problem says I....the platform we want to hit is the biggest thing on this side of the field. Once we break out and find it....we will follow the field map to our rig. Simple says I.

We broke out as planned in very...very....very...poor vis....to find ourselves running up to the largest bulk oil carrier I have ever seen.....as he did 12 knots to somewhere besides any place useful to us.

We reverted to the alternative approach method....go to the next biggest thing on the radar....and continued with our original plan.

[[email protected]]

C of G - here you go

1. Plot the position of the ship at the time of takeoff and measure the angle of the line of constant bearing from Base and the distance from Base to the ship’s position.

2. Using the square scale of the computer (the lower half of the card) set and mark the W/V using an X, then set the ship’s heading under the true course pointer on the whizz-wheel and mark the ship’s speed straight down from the W/V mark using ┴ or some other mark different to the W/V to avoid confusion.

3. Set the TAS under the centre circle and set the line of constant bearing from Base to ship under the true course pointer.

4. Adjust for relative drift using the ship’s marker, not the W/V.

5. The heading outbound will now be under the true course pointer.

6. The groundspeed outbound will be at the W/V mark.

7. The closing speed to the ship will be at the ship’s mark.

8. Time to intercept is a question of dividing the distance to run by the closing speed.


Hope this helps.

[eagle 86]

TT,
The only diff is that when you get low on fuel you can just pop it onto good old terra firma!
GAGS
E86

[B Sousa]

Remember , once in sight, if it gets bigger, your heading towards it. If it gets smaller, add power.

[C of G]

Crab,

Thanks for the info, :D I'll try it as an exercise when I return to the states. You may have a PM with a question about it, so as not to waste anyones bandwith who isn't interested. And thanks to everyone else for their stories. If I knew how to add a moving waypoint to a map and flew an aircraft with an FMS, or even radar for that matter, I would have a few new projects as well. At least I now have something to look forward to when I get the kit.:ok: