Tag Archives: buoys

HOW TO: Open water swim tips for triathletes

This follows up Part 1 and Part 2 of common triathlon swimming techniques and remedies, and Evan’s tips on the best use of a public pool for training and a simple effective front crawl stroke tip.

I’ve written various How To’s about different aspects of open water swimming in detail. This post is intended to be a general round-up of maybe useful advice for triathletes (based on substantial open water swimming experience).

(By the way, I’ll be indexing the How To articles soon similar to the Cold Water Swimming Index, to make it easier to navigate).

  • Open water practice is different and separate to pool practice, and equally essential. You need both.
  • Breathing and sighting are two SEPARATE activities. Breathe to the side. Sight from LOW over the water (think of it as crocodile eyes).
  • Getting through large breaking waves is simple and quick (once you’ve practised it). Dive under them. Don’t try to go over or through.
  • Different wind strengths and directions (to your swimming direction) change the water conditions in different ways. Practice in all weather conditions.
  • My idea of cold and your idea of cold are different because you are wearing a wetsuit. I prepare for my temperatures, you MUST prepare for yours, even with a wetsuit.
  • Practice in open water well in advance of your event, and practice repeatedly.
  • Navigation is a learned skill. Pick something above the water and work out how often you need to sight forward to swim straight. Expect the number to be low at the beginning.
  • Few people are as good at sighting as they think they are. Most are worse. There are too many variable to always be certain you are swimming straight.
  • Practice turns around buoys.
  • Common technique causes of drifting off-course are crossing over the body centreline with your arm and breathing to one side (where it unbalances the swimmer). Address these in your pool training.
  • Controlled breathing is important. Don’t hold your breath.
  • Don’t concentrate on lowering your stroke rate, or gliding. (Yes, I know many of you try to do the opposite).
  • Do increase your stroke rate. And train for this.
  • Forget Total Immersion.
  • Don’t kick hard.
  • Don’t sprint at the start.
  • Don’t wear new goggles for a race.
  • Don’t start at the front of a race wave if you’ve never done so before.
  • Expect full contact with other swimmers. To avoid contact start slightly behind the pack.
  • Swim to the side of the pack.
  • Don’t trust that the pack knows where it’s going.
  • My sport is more extreme and dangerous than yours but yours is more popular and with a higher fatality rate. That can be improved by better understanding of and preparation for open water.
  1. Just because water is soft, doesn’t mean it’s easy. Train appropriately.
  2. The best safety decisions are made outside of the water.
  3. Your wetsuit is NOT an open water safety aid. Don’t use it as such to enter a swim you are not sure you are capable of completing.

Know before you go

So let’s say like most of us, you don’t live close enough to the sea to able to look out your living room window before deciding whether to swim. But you want to know what the conditions at the coast are.

The easy solution is the use the Irish Marine Buoys. The map shows their locations.

All Marine databuoys around the coast belong to an international Station ID database. M5, my “local” buoy is actually Station ID 62094. The Sandettie Lightship in the English Channel is 62304. But I digress.

Let’s have a look at today’s readings.

Buoy M1 M2 M3 M4 M5 M6
Date 14 Feb 11:00 21 Oct 09:00 21 Oct 09:00 21 Oct 09:00 21 Oct 09:00 21 Oct 09:00
Atm. Pressure (mb) n/a 1021.4 1025 1020.2 1024.2 1024.2
Wind Speed (kn) n/a 15 5 18 13 n/a
Max Gust (kn) n/a 20 10 25 23 n/a
Wind Direction (°) n/a 250 290 270 280 240
Air Temp. (°C) n/a 9.8 12.6 11.9 10.9 13.4
Relative Humidity (%) n/a 84 58 73 78 75
Sig. Wave Height (m) n/a 1.1 1.2 n/a 1.1 1.6
Sig. Wave Period (s) n/a 4 6 n/a 4 7
Max Wave Height(m)
Max Wave Period(s)
Mean Direction (°)
Sea Temp. (°C) n/a n/a 14.6 13.2 13.7 14.1

The important stuff here for us are quite simple. All the buoys are Offshore but give an idea of the conditions within a region. M5 is about 50 miles offshore. M3 is closest buoy for Cork (because it gives a better idea what is coming than M5).

The Atmospheric Pressure. (All around 1024 in this case). And as I look out the window the sky is blue with little wind. It’s a high pressure,which given it’s October makes the night cold and the day dry.

Wind speed you are now familiar with (it’s in Knots here), but keep an eye also on the Max Gusts.

The wind direction is based on a 360 degree circle to indicate the direct from which it’s coming. 0 degrees is Due Nothe, 180 degrees is dues south. So readings here of 250 or 270 say the wind is coming roughly from the South West.

Sig. Wave Height is the height of the swell from trough to crest. Since it’s deep water, the swell isn’t breaking. Experience will help determine that this s once it hits the shore, but under 1.5 Metres is quite ok.

Sig. Wave Period is the time between peaks. I’ve mentioned this previously. Lower number (under 7 or 8) will indicate the swell is being driven by wind, and will be more messy at the shore.

The last (and for OW swimmers one of the most important) is Sea Temp.

Note: M5 is 50 miles out. Experience has shown that M5 reads higher than the shore temperature almost all the time. Which also makes sense if you think about. Offshore the water is deeper, and therefore is a larger volume, and less likely to be affected by wind than the shallower coastal water.

You can click on anyone of the buoys to get detailed hour reading, and see the change in wind or swell height.

Finally, when you look at the page, keep an eye on the latest news. It doesn’t often change, but some buoys go offline for months at a time, or get renamed as another (as is currently the case with M1 & M6)