Rule 38 applies only to vessels complying with the 1960 Collision Regulations whose keels were laid, or which were at a corresponding stage of construction, before 15 July 1977.
It lists narrowly defined exemptions concerning navigation-light ranges, colour specifications, positioning of lights and sound-signalling equipment. Some lasted four or nine years after entry into force; others are permanent exemptions from specified repositioning requirements.
These grandfathering provisions do not excuse the fundamental duties of look-out, safe speed, risk assessment or collision avoidance. The full source wording identifies precisely which requirement and time limit applies.
IMO COLREG 1972Official text
Full wording of the rule, reproduced from the official source below.
Any vessel (or class of vessels) provided that she complies with the requirements of the International Regulations for Preventing Collisions at Sea, 1960, the keel of which is laid or which is at a corresponding stage of construction before the entry into force of these Regulations may be exempted from compliance therewith as follows:
(a) The installation of lights with ranges prescribed in Rule 22, until four years after the date of entry into force of these Regulations.
(b) The installation of lights with color specifications as prescribed in Section 7 of annex I to these Regulations, until four years after the date of entry into force of these Regulations.
(c) The repositioning of lights as a result of conversion from Imperial to metric units and rounding off measurement figures, permanent exemption.
(d) (i) The repositioning of masthead lights on vessels of less than 150 m in length, resulting from the prescriptions of Section 3(a) of annex I to these Regulations, permanent exemption.
(ii) The repositioning of masthead lights on vessels of 150 m or more in length, resulting from the prescriptions of section 3(a) of annex I to these Regulations, until nine years after the date of entry into force of these Regulations.
(e) The repositioning of masthead lights resulting from the prescriptions of section 2(b) of annex I to these Regulations, until nine years after the date of entry into force of these Regulations.
(f) The repositioning of sidelights resulting from the prescriptions of sections 2(g) and 3(b) of annex I to these Regulations, until nine years after the date of entry into force of these Regulations.
(g) The requirements for sound signal appliances prescribed in annex III to these Regulations, until nine years after the date of entry into force of these Regulations.
(h) The repositioning of all-round lights resulting from the prescription of section 9(b) of annex I to these Regulations, permanent exemption.Signal Workflow
Decide the context first: manoeuvring in sight, restricted visibility, or distress.
The same whistle can mean very different things in a different context.
Check both the pattern and the interval.
For fog signals, the time spacing is part of the rule, not just the blast sequence.
When vessels in sight are approaching and you do not understand the other vessel’s intentions or actions, or doubt its collision-avoiding action, immediately sound at least five short, rapid blasts (Rule 34(d)).
Exam Focus
Three short blasts are astern propulsion, not a fog signal.
Rule 35(a)–(f) signals have a maximum interval of 2 minutes; the anchor and aground signals in (g)–(h) have a maximum interval of 1 minute.
Paragraphs (i)–(j) provide small-vessel alternatives.
Key Takeaways
Eligibility requires 1960-rule compliance and construction before entry into force in 1977
Only the specifically listed technical requirements are exempted
Some exemptions were transitional; specified repositioning exemptions are permanent
No general exemption from collision-avoidance duties
Common Mistakes
Assuming older vessels are completely exempt from COLREGs
Test Your Knowledge
Practise this topic and review the explanation for each answer.
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