What should fog signal be on a connected DP MODU?

When a DP MODU is connected, what should her fog signals be?

It would be Uniform I think. Two short and one long,

In accordance with Rule 35 (c) (Sound signals in restricted visibility ), a vessel restricted in her ability to manoeuvre shall, instead of the signals prescribed in Rule 35 (a) or (b) (Sound signals in restricted visibility ), sound at intervals of not more that 2 minutes three blasts in succession, namely one prolonged followed by two short blasts.

Navigational Aids

A MODU operating on DP and attached to the seabed is considered underway, not making way, and restricted in the ability to maneuver.

Lighting configuration:Restricted Maneuverability - Underway, not making way

  • Three all-round lights in a vertical line where they can best be seen. The highest and lowest of these lights shall be red and the middle light shall be white.

Note: Masthead lights, sidelights and sternlight are NOT required, as the MODU is not making way and anchor lights are NOT required, as the MODU is not considered as “anchored”.

Day shape configuration:

  • Three shapes in a vertical line where they can best be seen. The highest and lowest of these shapes shall be balls and the middle one a diamond.

See the follow-on question below, where additional lights and shapes may be required.

Are there additional navigation light requirements that apply to a MODU operating on dynamic positioning (DP), while obstructions exist in addition to the drilling equipment (e.g. ROV ops, subsea ops with the heave-compensated crane, etc.)?

Yes. Due to additional operations where obstructions exist to one side, the MODU may indicate the sides on which other vessels may and may not pass.

Lighting configuration:Restricted Maneuverability with obstructions - Underway, not making way

  • Restricted maneuverability lighting as described above (drilling only), PLUS;
  • Two all-round red lights in a vertical line to indicate the side on which the obstruction exists; and
  • Two all-round green lights in a vertical line to indicate the side on which another vessel may pass.

Day shape configuration:

  • Restricted maneuverability shapes as described above (drilling only), PLUS;
  • Two balls in a vertical line to indicate the side on which the obstruction exists; and
  • Two diamonds in a vertical line to indicate the side on which another vessel may pass.

MODU navigation lighting is also discussed on the USCG Navigation Center’s FAQ page by clicking here.

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Good luck keeping your fog horn on! Definitely not gonna make any new friends.

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I remember an H2S drill and everyone mustered on the helideck, then the Captain dismissed from drill with the horn. Surprised we didn’t lose any crew off the helideck. It made for a good rerun on the CCTV.

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Thanks all.

Looks like so far, we have one vote for Uniform and one vote for Delta.

Any tie breakers?

There’s no tie, @anchorman is right.

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Depends where you are. Canada has a Rule 42 that says…

  • (e) An exploration or exploitation vessel, when stationary and engaged in drilling or production operations, shall be equipped with a sound-signalling appliance that

    • (i) is powered by a reliable power source,
    • (ii) is provided with an auxiliary power source,
    • (iii) when operating, emits a rhythmic blast corresponding to the Morse letter “U” every 30 seconds,
    • (iv) has its maximum intensity at a frequency between 100 and 1 000 Hertz,
    • (v) has a usual range of at least two miles,
    • (vi) is installed at a height above the water of not less than six metres and not more than 30 metres, and
    • (vii) is so placed that the sound emitted is audible, when there is no wind, throughout the required range in all directions in a horizontal plane from the vessel.
  • (f) An exploration or exploitation vessel, when stationary and engaged in drilling or production operations, shall, whenever the visibility in any direction is two miles or less, operate the sound-signalling appliance described in paragraph (e) in lieu of the sound signal described in Rule 35.

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That’s what I thought. Any knowledge of other coastal states which override rule 35?

Just a copy paste from USCG and COLREGS

I guess some background to the reason your asking the question would be helpful.

In the UK it is Uniform I think.

I didn’t realize it was different in other countries.

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I find it very odd that these signals (UK, Canada) are not aligned with the International ColRegs. Having gotten original U.S. licenses in the 70’s for International, Inland and Great Lakes there were some differences and there was also a Western Rivers Rules. One big one was the Great Lakes fog signal for power driven vessels underway that was 3 short blasts every minute. All of those sound signals were pretty much consolidated/aligned in the 80’s with the International Rules. I believe Canada still does some drilling in Lake Erie and I am now curious as to what the drill barges would sound or if they’d sound anything as they might be jack up rigs.

Am i reading the application section of Canadian Colregs correctly in that it would apply to canadian vessels anywhere in world outside of another countries colregs line? So like a canadian drill ship in the gulf of mexico would sound these signals? Or just exploring on a canadian license to drill?

Well, if it’s in the GOM then I would assume it would be two spits in a dip bottle and then a hardy “Yee Haw” out the window.

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I would think no, they’re operating under their USCG Certificate of Compliance. That said, it’s been years for me, but the USCG always wanted the lights and signals in 33 CFR 67.10 once latched up right or wrong. They always checked to see if we switched from international Morse-U to the U.S. 2s every 20s. Has that changed?

In international waters ColRegs and IMO rules apply. EEZ (OCS) is international waters by UNCLOS. Any special National Rules only apply within territorial waters.

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That could apply somewhere like in Lake Winnipeg or the Great Slave Lake which isn’t directly connected to either the oceans or the Great Lakes. I think somewhere they would have to say where that does and doesn’t apply and I can’t believe it would apply anywhere the International Colregs would apply.

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In SE Asia you get different answers from different countries.
Drilled in a few and we always checked.