Can I wear sunglasses on the bridge?
The myths that can arise from not reading a MGN
Relevant documents: MAIB report, MGN 357, Code of Safe Working Practice for Merchant Seafarers
I’ve never heard of this coming up in an MCA exam, but it’s in a published MGN so it could well do so. Rather, this article provides information on a subject of general interest, helps officers understand how to make their bridge and ship a bit safer, and cautions against believing without question everything that you’re told and especially against passing that same information on.
On at least three occasions I’ve been told by well-intentioned crew mates that it’s illegal to wear sunglasses on the bridge. This is a myth, and it’s one that has a great deal of urban legend potential. Because it sounds plausible.
Let’s start by examining where the misconception came from in the first place.
In August 2006 the sailing yacht Ouzo left the Isle of Wight, bound for Dartmouth, Devon. The body of one of her crew was found on the 22nd of August, with a search finding the bodies of the remaining two crewmembers the next day. No collision had been reported.
The MAIB recovered and analysed VDRs (Voyage Data Recorders) from vessels that had been in the vicinity. It was found that a ro-ro passenger ferry running between Portsmouth and Bilbao, the Pride of Bilbao, had had an encounter with a yacht early on the 21st August. The lookout on the ferry hadn’t seen the yacht till it was very close ahead; the OOW had tried a last-minute manoeuvre to avoid a collision and believed that he had been successful. He saw a single red and then, possible a white light astern of the ferry after the incident and considered this sufficient so assume that the yacht was safe. No further action was taken.
A number of issues were considered by the investigation, but the only one we’re looking at today is:
Why did the lookout not see the yacht earlier?
The lookout was wearing reactolite, or photochromic lensed glasses. At night these are clear but during the day they darken in response to UV light. His glasses were tested ashore by a third party to determine whether they might have had an adverse effect on his night vision.
The third party found that the optical transmission of these glasses was no more than 80% efficient. This is compared to the 94.7% and 99.4% efficiency of ordinary uncoated and coated lenses.
From these findings, it was determined that the lookouts glasses would have been a contributing factor as to why the Ouzo’s lights were not seen sooner.
It is considered good practice for a bridge watchkeeper to arrive on the bridge 10-15 minutes prior to the start of their watch. This is to allow time for the handover and to let their eyes adjust. The lookout had arrived on the bridge having just carried out safety rounds of brightly lit passenger and car decks, then arrived on the bridge via the chartroom where a red light filter had been removed.
The institute for Opthalmology stated that:
From the observer’s point of view, the decline in thresholds found after 5 – 6 mins appear to be less significant in terms of his/her ability to see in the dark. Visual function here is mediated by rod photoreceptors which are critical in detecting thresholds at low luminance levels. Rods function over a greater dynamic range than cones and are the main photoreceptor population that functions in a truly dark adapted state. Hence, while the observer may report a significant improvement in dark adaptation in the first 5 – 6 mins, this is subjective.
Appropriate measurements reveal that visual sensitivity is still increasing rapidly after the first 5 – 6 mins when cone function has fully adapted but rod function has not. Hence, there are strong grounds for arguing that the handover period should be extended in a fully dark environment for 20 – 30 mins. However, this may be impractical in marine conditions. In spite of this, there are grounds for arguing that the handover time should be extended such that it covers a time during which rod sensitivity is at least improving. This would mean extending the handover time to 15 mins. This handover period should be within a dark visual environment.”
This goes some way towards providing scientific justification for the traditional arrival on the bridge, 15 minute prior to start of watch.
At the time of the accident there was no guidance on the wearing of photochromic lenses for lookouts. The accident occurred in August 2007'; the MAIB report was published in April of 2007, and in December 2007 the MCA published MGN 357:
‘On the basis of these findings, the MAIB recommended that photochromic lenses should not be worn for lookout duties at night. This notice advises operators, masters/skippers and seafarers on precautions to be taken by those with lookout duties at night.’
So, back to the myth of sunglasses on the bridge. Sunglasses are mentioned in the Code of Safe Working Practices for Merchant Seafarers amendment 7 2022:
3.13 Sunglasses
3.13.1 The bright light from the sun reflecting off the surface of a calm sea or from ice caps in the Polar regions, or from the vessel itself, can dazzle the seafarer and cause damage to the eyes.
3.13.2 In these conditions, seafarers working on the bridge or on the open deck should wear sunglasses, which are an important piece of protective equipment, rather than tinted eye protection. For protection on the bridge, collective protection systems should always be considered; for example, sunblinds.
3.13.3 The following guidance should be considered when purchasing sunglasses.
The lens tint should be neutral – ideally either grey or brown as these cause the least colour distortion.
The lens tint should be no darker than 80% absorption.
A graduated tint, with the darkest at the top of the lens, lightening towards the bottom, may be useful.
Glasses should be CE marked and to the British Standard BS EN ISO 12312- 1:2013+A1:2015. BS EN ISO 12311:2013 ensures that the sunglasses offer a safe level of ultraviolet protection.
3.13.4
Photochromic lenses react with UV radiation by darkening. Sunglasses with photochromic lenses must not be worn during the hours of darkness as they can significantly reduce night vision. Information is given in MGN 357(M+F).
3.13.5 Polarised lenses reduce the amount of light passing through the lens by selective filtering of certain electromagnetic spectral planes. Polarised lenses should not be used when viewing instrument panels as the visibility of some images may be unclear. In some situations, for example, when navigating in shallow water, the wearing of these lenses may be beneficial as they can reduce the reflected glare from the surrounding water. Seafarers should be aware of the benefits and limitations of polarised lenses.
3.13.6 All frames should be well fitting and large enough to allow sufficient protection from oblique sunlight. All seafarers requiring a spectacle prescription must have a clear pair of correcting lenses but can have prescription sunglasses as their second pair. The wearing of non-prescription sunglasses on top of prescription glasses is not permitted. For navigational watches during the hours of darkness, the wearing of any type of sunglasses is not recommended.