Boating safety in winter - what every NZ boatie needs to know
Winter boating in New Zealand is entirely doable, and on the right day it's genuinely excellent. But it asks more of you than a summer run up the coast. The water is colder, the days are shorter, and there are fewer boaters around to help if something goes wrong. Maritime New Zealand is clear that preparation and knowledge are what make the difference between a good day out and a dangerous one.
The cold water reality
The most significant risk in winter boating isn't bad weather: it's cold water immersion. New Zealand's coastal and inland waters are cold from April through to September, and cold water affects the body fast. According to Maritime NZ's cold water survival guidance, immersion in cold water can be fatal within 30 to 40 minutes. In alpine lakes, that window is even shorter.
The important thing to understand is that it's the water temperature, not the air temperature, that matters. A calm, clear winter day can feel perfectly comfortable standing on the boat. Fall into the water and the picture changes immediately.
Dress for the water. Not the weather.
Before you leave the ramp
Most incidents on the water in winter are preventable. The majority come down to poor preparation rather than unavoidable bad luck. Work through these before every trip:
- Check the MetService marine forecast, not the land forecast. They are different, and the marine forecast is the one that matters. Check it the night before and again in the morning.
- File a float plan. Tell someone ashore what boat you're in, where you're going, your expected route, and when you plan to be back. If something goes wrong, this is what gets searchers looking in the right place.
- Test your batteries. Cold kills batteries that were already borderline. If they're more than a few years old and performing poorly in summer, replace them before winter.
- Check your nav lights. Shorter days mean a genuine chance of returning after dark. Check all lights are working and carry a spare torch.
- Check your flares are in date. Out-of-date flares are not reliable. Check the expiry and replace anything that's past it.
- Charge your VHF radio and PLB. Communication devices need to be fully charged before departure, every time.
- Check the bung is in. It sounds obvious. It still gets missed.
If the boat has been sitting over winter, work through our guide to looking after your boat over winter in New Zealand before heading out. It covers the mechanical checks that matter most before the first trip of the season.
Burnsco's winter boating checklist is also a practical reference worth bookmarking.
What to wear on the water in winter
Layering is the key, and the lifejacket goes on top of everything else, not underneath your jacket. A lifejacket you can't inflate or that gets tangled in outer clothing isn't doing its job.
- Base layer: merino wool or synthetic. Not cotton: cotton holds moisture and accelerates heat loss.
- Mid layers: fleece or down for insulation. Add more than you think you'll need.
- Outer layer: waterproof and windproof. A good foul weather jacket makes a significant difference.
- Lifejacket: always the outermost layer, correctly fitted and in good condition.
- Hands and head: you lose significant heat through an uncovered head. Gloves matter too, particularly if you're handling lines in cold conditions.
If you're fishing from a small open boat, kayaking, paddleboarding, or riding a jet ski in winter, a wetsuit or drysuit is worth serious consideration. The margin for error in those situations is much smaller.
If you end up in the water
If you go overboard in cold water, the instinct is to thrash and swim hard for the boat or shore. Resist it. Thrashing burns energy rapidly and accelerates heat loss. The Safer Boating guidelines recommend the HELP position (Heat Escape Lessening Posture) as the first priority if you're wearing a lifejacket and waiting for rescue.
- HELP position (alone): cross your arms tightly over your chest, press your thighs together, and draw your knees up toward your body. This reduces heat loss from the body's core.
- Huddle position (group): press the sides of your chests and lower torsos together, intertwine legs, and keep talking to each other. Put children in the middle of the group, as they lose heat faster than adults.
- Stay with the boat. Even an overturned boat is much easier to find than a person in the water. Climb onto it if you can.
- Know your limits. Maritime NZ notes that even a strong swimmer wearing a lifejacket in light clothing has roughly 1.85km of realistic swimming range in 10 degree water.
For a more detailed guide to cold water immersion and survival, including what happens to the body at different water temperatures, read our dedicated article on surviving in cold water.
What to carry on board in winter
In addition to your standard safety gear, these items earn their place in winter:
- Two waterproof means of communication: a VHF radio and a PLB are the recommended combination. Mobile phones don't count as a reliable backup.
- Spare warm clothing in a dry bag, for yourself and for passengers who weren't expecting conditions to turn.
- Hot drinks in a thermos. Practical and morale-boosting.
- A torch with spare batteries.
- First aid kit.
- Up-to-date flares.
Know when to stay ashore
The most important safety decision in winter boating is the one made before you leave. If the forecast is marginal or deteriorating, stay ashore. There is no boating trip worth a serious risk in winter conditions.
Fewer people on the water means fewer people nearby if something goes wrong. A mechanical failure or weather change that would be inconvenient in summer becomes a genuine emergency in winter if help is 45 minutes away and the water is 12 degrees.
Coastguard's message is consistent: wear your lifejacket, check the weather, take two ways to communicate, and tell someone your plan. Those four things address the majority of serious incidents on the water. For more on winter boating and where to go when conditions are right, read our winter boating guide.
Mariner Insurance covers all types of boats and watercraft on New Zealand's water, year-round. If you're not sure whether your current policy is right for how you use the boat in winter, read our article on whether you need boat insurance for the winter, or get in touch directly.