Weather and sea state directly affect everything aboard a SAR vessel — when operations are possible, how fatiguing a watch will be, what PPE is required on deck, and crucially, what conditions the people you are trying to rescue have been enduring.
It is worth keeping in mind that while sea conditions affect crew safety and operational capability, survivors in distress have no shelter from those same conditions. People on an overcrowded boat in Beaufort 4 have been exposed, cold, seasick, and exhausted — often for hours or days, with little or no food or water. Understanding conditions is not just about managing your own safety — it shapes how you respond to the people you are there to help.
Operational limits
Every organisation sets its own operational limits for different conditions. These are defined in your organisation's SOPs — Standard Operating Procedures. This module gives you the framework to understand those limits. Before your deployment, ask your team leader to walk you through your specific vessel's approach.
What you'll cover
The Beaufort scale — wind speed in knots, wave height, and visibility
What each sea state means for crew safety on deck and for survivors
How weather conditions affect SAR operations
How to use Windy.com to read a weather forecast before deployment
VHF radio basics — channels, phonetic alphabet, and radio etiquette
Estimated time
10 minutes — followed by a knowledge check
Section 1 of 4 — Interactive
The Beaufort scale
The Beaufort scale is the international standard for describing wind force and resulting sea conditions. It runs from 0 (flat calm) to 12 (hurricane). You'll hear it used constantly aboard — "sea state 4," "Beaufort 6." Use the slider to explore each level.
This is a reference tool — you don't need to memorise the numbers. What matters is building a feel for what different conditions look and feel like, and what they mean for the people on deck and the people in the water.
3
Gentle breeze
Wind
7–10 kts
Wave height
0.6–1.0 m
Visibility
Good
Large wavelets with crests beginning to break. Scattered whitecaps. Foam has glassy appearance.
Safety on deck
Comfortable working conditions. Use grip points when moving. Spray possible — be aware of wet surfaces. Standard PPE applies.
For survivors
Uncomfortable on a small or overcrowded boat. Spray and vessel movement will be affecting anyone without shelter. People will be tired and cold even in these conditions, particularly after extended time at sea.
Section 2 of 4
How weather affects operations
Understanding the different elements of weather helps you understand why decisions are made the way they are — and prepares you for what you'll encounter during a deployment.
Wind direction
Wind direction affects vessel positioning during rescue. The Master positions the ship to create a lee — a sheltered side — for RHIB operations and for survivors boarding. This explains many of the manoeuvres you'll observe during a rescue.
Visibility
Fog, rain, haze, and spray all reduce search effectiveness. Spotting a low-lying overcrowded boat or persons in the water in poor visibility is genuinely difficult. Bridge lookout and deck alertness become critical when visibility is reduced.
Water temperature
Water temperature determines survival time for anyone in the sea. Mediterranean summer water (24–28°C) gives significantly more time than winter water (14–18°C). This affects both rescue urgency and the medical priorities when survivors come aboard.
Swell vs wind waves
Swell comes from distant weather systems and can create significant wave height and motion even when local wind is light. A low Beaufort reading does not always mean easy conditions — combined sea states can be more challenging than either alone.
Seasonal patterns — Central Mediterranean
Summer (May–September) typically brings calmer conditions, better visibility, and warmer water — though the Sirocco and Mistral can develop quickly. Winter brings more frequent adverse weather, reduced visibility, colder water, and shorter daylight hours. Both seasons present distinct challenges.
SAR operations and weather
SAR organisations aim to operate in conditions that allow safe and effective rescue. In practice, operations are less frequent during severe weather — both because of what is operationally achievable and because the safety of the rescue crew must be considered carefully. If you have questions about how your organisation approaches this balance, speak to your team leader. They can explain your vessel's specific approach.
Section 3 of 4
Reading weather with Windy
Windy.com is a free, widely-used weather visualisation tool that is particularly useful for maritime forecasting. Many SAR professionals use it before and during deployments to get a clear picture of conditions ahead. It is intuitive, visual, and accessible on mobile.
You don't need to become a meteorologist — but knowing how to pull up a basic forecast for your operating area before departure is a useful skill and helps you understand operational briefings better.
Getting started
1
Go to windy.com or download the Windy app. No account needed for basic use.
2
Navigate to your operating area — for Central Mediterranean SAR, zoom into the sea between Libya, Malta, and Lampedusa.
3
Use the layer selector (bottom of screen on mobile, left panel on desktop) to switch between what you want to see.
4
Use the time slider at the bottom to step forward through the forecast — typically reliable 3–5 days ahead.
5
Tap any point on the map to get a detailed forecast graph for that exact location — wind, gusts, waves, rain, and more.
Key layers to know
Wind
Shows wind speed and direction as animated streamlines. The darker and faster the animation, the stronger the wind. Colours range from blue (light) through green, yellow, orange to red (storm force). This is the most useful layer for a quick overview of conditions.
Waves
Shows combined wave height in metres. Switch to "Swell" to see swell specifically versus wind-driven waves. Particularly useful for understanding what conditions RHIB crews will face even when local wind appears light.
Rain / clouds
Shows precipitation and cloud cover. Rain squalls and cloud cover affect visibility significantly. The "Radar" overlay shows real-time precipitation if available in your area.
Visibility
A dedicated visibility layer is available — useful for planning search operations where spotting targets at distance is critical. Fog and haze show clearly on this layer.
Windy is a planning tool, not an authority
Windy is excellent for getting a feel for upcoming conditions and for understanding operational briefings. Your vessel's bridge receives official forecasts and NAVTEX bulletins. Operational decisions are made by the Master and STL based on those official sources — not on a crew member's Windy app. Use it to inform yourself, not to second-guess decisions.
Section 4 of 4
Radio basics
VHF radio is the primary communication system aboard vessels. You won't be operating the ship's main radio — that is the bridge's responsibility — but you will use handheld UHF radios for crew coordination during operations, and you may need to use radio communication in other contexts. Understanding basic radio etiquette and the phonetic alphabet is expected of all crew.
Think — Push — Talk — Release — Listen
Before every transmission: think about your message. Push the PTT (push-to-talk) button. Talk slowly and clearly. Release the button. Listen for a response. This sequence prevents the most common radio errors.
VHF vs UHF — knowing which radio you're using
VHF — ship's radio
Public communication for ship-to-ship and ship-to-shore. Everyone can hear you. Range is line-of-sight — it depends on antenna height rather than being a fixed distance (a vessel with a tall mast has much greater range than a handheld). Operated from the bridge. Channel 16 is the international distress and calling channel — always monitored.
UHF — handheld radio
Used for onboard crew communications and with RHIBs during operations. Shorter range — approximately 2 miles for a handheld. More frequencies available. This is the radio you will most likely use day to day as a crew member.
The 4 golden rules
Clarity
Speak calmly and clearly. A little slower than normal. Normal tone — do not shout.
Simplicity
Keep messages simple enough for all listeners to understand — not everyone is a native English speaker.
Brevity
Be precise and to the point. Think before you transmit. Radio is a shared resource.
Security
Do not transmit sensitive information. Use pre-agreed code words where applicable. Avoid using people's names on VHF.
Prowords — radio vocabulary
OVER
End of transmission — a response is required. Always use this when you expect a reply.
OUT
End of transmission — no response required. The conversation is closed.
COPY / RECEIVED
I have received and understood your message. Note: ROGER is no longer formally recognised — use COPY or RECEIVED instead.
GO AHEAD
Transmit — I am listening. Used to invite the other station to proceed with their message.
WILCO
Will comply — I understood your instruction and will carry it out.
SAY AGAIN
Please repeat your last message. Do not say "REPEAT" — this has a specific meaning in military contexts and can cause confusion.
STANDBY
Wait — I acknowledge your call but cannot respond immediately. I will come back to you.
AFFIRMATIVE
Yes. Use this instead of "yes" on radio for clarity.
NEGATIVE
No. Use this instead of "no" on radio for clarity.
UNREADABLE
Spoken three times — I cannot understand your transmission. Use an alternative means of communication.
RADIO CHECK
Requesting confirmation of signal strength and readability. Responses: LOUD AND CLEAR (good signal), WEAK BUT READABLE (weak but understandable), WEAK AND DISTORTED (weak and unreadable).
Bridge responds: "Deck, Deck — Bridge. Loud and clear. Over."
→
Deck confirms: "Copy, Bridge — loud and clear. Out."
Note the structure: who you are calling first, then who you are. State the channel. End with OVER when expecting a reply, OUT when closing. Always identify the station called before the station calling.
You cannot speak and listen at the same time
This is the most common mistake. While you are transmitting, you cannot hear anything. Keep transmissions short, release the PTT button promptly, and listen for responses. Never interrupt a conversation on the radio unless it is an emergency.
The NATO phonetic alphabet
Used to spell out letters clearly over radio where similar-sounding letters (B/D/E/P etc.) could be misheard. You'll hear it used constantly — for vessel names, call signs, positions, and identifications. Familiarise yourself with it before your deployment.
A
Alpha
B
Bravo
C
Charlie
D
Delta
E
Echo
F
Foxtrot
G
Golf
H
Hotel
I
India
J
Juliet
K
Kilo
L
Lima
M
Mike
N
November
O
Oscar
P
Papa
Q
Quebec
R
Romeo
S
Sierra
T
Tango
U
Uniform
V
Victor
W
Whiskey
X
X-ray
Y
Yankee
Z
Zulu
Channel 16
Channel 16 VHF is the international distress and calling channel — monitored at all times by all vessels and coastguard stations worldwide. It is never used for routine conversation. If you ever hear a MAYDAY on any radio, alert the bridge or nearest officer immediately without touching the radio yourself.
Radio distress signals
Three standardised radio signals are used internationally to indicate the urgency of a transmission. Every crew member should know them — not to broadcast them, but to recognise them immediately and respond correctly.
MAYDAY
Distress
The vessel or a person is in imminent or grave danger and requires immediate assistance. This is the highest priority signal. All other radio traffic must cease. If you hear MAYDAY, alert the bridge immediately — do not touch the radio yourself unless directly instructed.
PAN PAN
Urgency
The vessel or a person has a very urgent message regarding the safety of the vessel or a person aboard — but immediate assistance is not yet required. This takes priority over all traffic except MAYDAY. It may escalate to MAYDAY if the situation deteriorates.
SÉCURITÉ
Safety
An important navigational or meteorological warning is being transmitted — hazards to navigation, weather warnings, or critical safety information. No immediate danger, but all vessels should listen. Commonly broadcast by coastguard stations.
Priority order
MAYDAY takes absolute priority. PAN PAN takes priority over all traffic except MAYDAY. SÉCURITÉ takes priority over routine traffic. If you hear any of these signals, stop transmitting and alert the bridge immediately.
Knowledge check
Before you move on
Six questions — these focus on understanding and application, not memorisation of specific Beaufort numbers.