KVR and SeeSchStrO: What applies in fog and in the fairway

​I was actually perfectly prepared for the approaching storm: wind resistance minimised, navigation lights switched on, everything lashed down, the boat secured, my position noted down and the hood pulled down over my nose. Now all that remained was to weather the storm – but suddenly, from the wall of water that barely allowed the bow to be seen, individual sounds could be heard: one long one, followed by two shorter ones.

What to do in such situations at sea is set out in Section III of the International Regulations for Preventing Collisions at Sea (COLREGS): ‘Conduct of vessels in conditions of reduced visibility’. When they think of this, many people’s first thought is of fog. However, according to Rule 3, this also includes reduced visibility caused by heavy rain, snow, even sandstorms or other ‘severe weather conditions’. Visibility is deemed to be reduced whenever vehicles can no longer see one another due to such circumstances.

Specific examples

KVR in conditions of reduced visibility: a major levelling-off

As the saying goes, ‘All cats are grey in the dark’ – in the KVR, this applies in conditions of poor visibility. Whilst it is still possible to identify the different vehicle categories (see Episode 3) at night by their lighting patterns, this becomes virtually impossible when visibility is poor. All that remains then are audible signals, the Automatic Identification System (AIS) and radar, although the latter also provides no information about the type of vehicle detected. Furthermore, the AIS does not detect all vehicles.

The provision of the signals stipulated for such cases in Rule 35 of the KVR Audible signals is, however, compulsory for all vessels. The term ‘fog signals’ is often used, but they apply to all types of reduced visibility. Motorised vessels then make themselves known by sounding a long blast – or two long blasts if they are not travelling through water (engine stopped). Sailboats, fishing vessels, tugs, vessels unable to manoeuvre, and vessels with restricted manoeuvrability or draught must all sound the signal described at the beginning in unison. These signals must be sounded at least every two minutes.

Boats under twelve metres in length may, as an alternative, emit another loud acoustic signal. Otherwise, when vessels are underway, only motorised and other vessels can ultimately be clearly distinguished by acoustic signals alone.

​Acoustic signals in conditions of reduced visibility in accordance with Rule 35 of the KVR

​Key: • = short note (approx. 1 sec.), – = long note (4–6 sec.)

A cautious approach without making eye contact

Consequently, the order of priority for the various categories of vessel under Rule 18 no longer applies in conditions of reduced visibility. Instead, all vessels must act uniformly in accordance with Rule 19: if the fog horn of another vessel is heard ahead rather than abeam, and there is a suspicion of a possible risk of collision, one must reduce speed to the minimum necessary to maintain steering control. Thereafter, one must manoeuvre with the utmost caution and, if necessary, come to a complete stop should the other vessel continue to approach.

In the absence of visual contact, therefore, no prescribed evasive manoeuvre is carried out in the event of an imminent risk of collision; instead, speed is initially reduced only. This applies to the other vessel as well, thereby slowing down the mutual approach accordingly. The situation only changes once both vessels come within sight of one another. In that case, the rules on giving way for vehicles within sight of one another apply once again. Until then, Rule 19 on reduced visibility takes precedence over Rules 12 to 18.

In conditions of reduced visibility, it is therefore advisable to keep a particularly watchful lookout so that you can react promptly in accordance with the rules as soon as you make visual contact. And what if you hear the sound signal of another vessel coming from across the bow or astern? In that case, you should not alter your course in that direction.

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The pinnacle of radar analysis

In addition to acoustic perception, Rule 19 also takes into account the situation where another vehicle is detected solely by radar. The first step would then be to analyse the radar imagery to determine whether a close-proximity situation is developing and whether there is a risk of a collision.

If this is the case, a course change to port should be avoided when a vessel is ahead rather than abeam – except when overtaking. The idea behind this is that if both vessels alter course to starboard, they will safely give way to one another. If a vessel is detected abeam or astern of the vessel, a course change in its direction should be avoided.

In practice, however, devising a suitable evasive manoeuvre based solely on radar information is not quite as straightforward as it might initially appear. Professionals use an advanced form of radar plotting for this, which works with so-called ‘what-if’ scenarios: At what point would I need to alter my course by how many degrees, or slow down by how much, to achieve a specific passing distance? This, however, takes practice, especially as the MARPA function (Mini-Automatic Radar Plotting Aid) on radar systems commonly found on yachts often reaches its limits here.

Even without the relevant skills, however, you can still use the radar to see whether the thick weather is concealing other vessels, where they are located and how they are moving. The MARPA function can also be used to determine how close you will get to them and how much time remains until then. Apart from that, in conditions of reduced visibility, it is particularly important that your own yacht is reliably detected by others on the radar – keyword Radar reflector.

Detection by AIS

As previously explained, the KVR makes no mention whatsoever of the AIS. Accordingly, there is no provision for taking evasive action based on AIS data in conditions of reduced visibility. This is because there are legitimate doubts regarding the timeliness and accuracy of the position and movement data displayed. Ships have already collided with one another even though, according to the AIS, they were still a considerable distance apart.

Nor does the vessel type displayed on the AIS, in the absence of visual contact, impose any obligation to give way or maintain course. This is because the rules on right of way in traffic and on giving way between sailing vessels or motorboats only apply when both vessels are within sight of one another – and, according to Rule 3(k), this means being able to see one another visually and not merely electronically.

Nevertheless, it can be helpful to know that there are vessels in the vicinity which you must give way to when they come into sight. However, the AIS does not always display these in full.

A night-time role reversal in the Elbe estuary

Just as Rule 19 takes precedence over the other alternative rules of the KVR under certain conditions, regional regulations may also take precedence over the KVR in some areas. The practical implications can be observed, for example, at night in the area of the Elbe estuary: many large vessels suddenly change their lighting patterns there. Some switch from three red all-round lights to the red-white-red light combination – others do the reverse.

Do vessels with deep draught and limited manoeuvrability suddenly swap roles here? But how can a container ship or cruise liner become a dredger or cable-laying vessel? The solution lies in a narrow line on the nautical chart labelled ‘outermost boundary of the maritime shipping lanes’.

Upon entering the area covered by the German Maritime Traffic Lanes Regulations (SeeSchStrO), vessels with limited draught become vessels with right of way – a category which does not exist as such under the KVR. Meanwhile, vessels with right of way that are leaving the area revert to being vessels with limited draught.

KVR and SeeSchStrO: Roads and Waterways

The SeeSchStrO applies to maritime shipping lanes in German territorial waters. Whilst the latter extends to a distance of twelve nautical miles from the coast, maritime shipping lanes comprise the waters from the seaward boundary of inland waterways up to a distance of three nautical miles seaward of the baseline – of a defined coastline. In addition, there are fairways under the SeeSchStrO which may also extend beyond the three-nautical-mile zone. These comprise all laterally marked shipping lanes in German territorial waters – that is, those with red and green boundary buoys.

Within its scope, the SeeSchStrO does not replace the KVR, but supplements it with additional regulations. Among other things, it introduces a blood alcohol limit for sailing under the influence of alcohol, requires the appointment of a skipper before setting sail, sets out administrative offences and defines specific navigation marks as well as additional categories of vessel. In some cases, there are also differing provisions regarding the behaviour of vessels in relation to one another – in such instances, the SeeSchStrO takes precedence over the KVR as a specific rule within its scope of application.

Whilst general regulations, such as the aforementioned navigation marks, apply on all maritime waterways, some provisions relate explicitly to navigable channels, meaning that the SeeSchStrO applies in full only in these areas.

Right of way through obedience

This applies in particular to Section 25 of the SeeSchStrO, which contains one of the most significant deviations from the KVR: whilst the latter makes no provision for right of way, it is expressly introduced here. Accordingly, vessels following the course of a fairway have right of way over all others. Any vessel entering a fairway, crossing it, leaving its anchorage or berth, or turning within the fairway must give way to such vessels, regardless of the type of vessel.

Anyone required to give way must make it clear through their manoeuvres that they will wait until the through traffic has passed. This is intended to prevent the through traffic from being forced to take evasive action by other vessels. Two vessels following the fairway shall give way to one another on the starboard side when on opposite courses – a rule which, incidentally, also applies to sailors. However, all fairways under the SeeSchStrO are also narrow fairways under Rule 9 of the KVR, meaning that the rule to keep to the right applies, so this should only occur in exceptional cases.

However, only vessels that are actually following the course of the fairway are to be regarded as through traffic. Sailboats crossing the fairway are therefore not considered through traffic; they must give way to one another in accordance with Rule 12 of the KVR and must also give way to through traffic. As a guideline, the course over ground (COG) must not deviate by more than ten degrees from the course of the fairway in order to be classified as through traffic.

The only exception to this is the right of way enjoyed by vessels in the main fairway over vessels in a secondary fairway. Vessels in the main fairway have right of way even if they do not follow the course of the fairway exactly.

The right of way

Outside the fairway, vessels must, as a general rule, give way in accordance with the KVR once again. The right of way rule set out in Section 25 of the SeeSchStrO ceases to apply here – unless special local regulations apply or the vessels have a special status.

As already mentioned, the SeeSchStrO introduces additional categories of vessel to supplement the KVR – including the aforementioned vessels with right of way. These are vessels that exceed certain dimensions and, due to their size and draught, are compelled to use the deepest part of the navigation channel. They are regarded as vessels with restricted manoeuvrability within the meaning of the KVR, which explains their lighting arrangements. All vessels that are not themselves manoeuvre-impaired or unable to manoeuvre must therefore give way to them.

Overall, the SeeSchStrO goes into much greater detail and is considerably more comprehensive than the KVR. To address all the regulations individually would go beyond the scope of this article. Among other things, it also contains specific rules of conduct for individual areas such as the Kiel Canal (NOK), for certain types of craft such as surfers and water skiers, and for special situations such as passing through locks and in the event of shipping accidents. In addition, there are a variety of markings with which one should be familiar when travelling within its area of application.

Specialists are given priority

In some cases, specific regulations also apply. For example, according to the Hamburg Port Traffic Regulations (HVO), the fairway in the Hamburg harbour area extends from bank to bank – the buoys serve solely to mark the deep-water channel. This means that, where applicable, right of way may also have to be given outside the buoy line. Furthermore, based on official notices, there may be isolated local exceptions to the SeeSchStrO, such as the requirement to keep to the right.

As a general rule, the principle applies that the more specific regulation takes precedence. The regional HVO therefore takes precedence over the SeeSchStrO, and the SeeSchStrO, as a national regulation, in turn takes precedence over the KVR as an international set of rules. Where no more specific rules apply, the KVR remains authoritative regarding rules of way on the seaward side of inland waters. The same applies to cases not covered by special provisions.

Anyone who has a good grasp of the KVR therefore has a solid foundation for behaving correctly in maritime traffic. This provides a basis on which to build when navigating in areas where special regulations apply. Whether this is the case and how to comply with these regulations should, where possible, be clarified before setting off on a trip. This applies in particular to trips abroad.

Book recommendations

KVR. SeeSchStrO It brings together the collision prevention rules, the Maritime Waterways Regulations and the Ems Estuary Navigation Regulations. The book serves both as a training aid and as a reference guide on board.

Regulations Governing Maritime Waterways provides commentary and explanations on the regulations governing German maritime waterways. It also covers the rules for the prevention of collisions, as well as lights, signal devices and sound signals for key types of vessel.

Electronics make shipping traffic more visible, but they can also create a false sense of security. Are sailors now relying too heavily on AIS and chartplotters? Share your views and experiences in the comments.