What are the differences between OWS in a lake vs. ocean?

The taste...

...and those darned pesky tidal currents...

All of my tris except one have been tropical ocean swims. But in the summer my OWS is almost entirely in cold lakes.

*The same ocean can be very different depending on time of day or weather. More variability than in lakes. You might have flat water for a practice swim the day before, then high waves and strong current for the race, or vice versa. Conditions can even change between different start waves in a big race, or during a swim. In my opinion you need  better swim fitness and a higher OWS comfort level than for the same distance in a pool or lake to deal with this.

*Visibility varies just as in lakes. I have swum in everything from so black/opaque that I can't clearly see my fingers (Singapore) to pure blue where I could see tens of feet down (Hawaii, Indonesia). The former is generally harder to deal with mentally, but I also find it disconcerting where I can see a long way out to sea underwater (Hawaii); I try to keep looking straight ahead and not think about what might be incoming LOL.

*Most of my ocean tris have very little shark risk but there are jellyfish. I know I'm a bit more relaxed swimming in lakes because I don't have to think about them!

*Ocean waves/currents are generally bigger and more noticable. It's possible for the waves to be so high that sighting is difficult. Particularly annoying are strong onshore or offshore currents. The latter make it hard to get started; the former, hard to finish. Again, you need to be a stronger swimmer for the same distance to deal with this. Times tend to be slower despite buoyancy--I can do 1500m in 25 flat in a pool; my best ocean time is almost 3 minutes slower. Drafting can be VERY useful; if you are a good swimmer, people may quite aggressively try to draft off you--slapping your feet, swimming parallel for a long way, etc.

*As for vertigo, not sure. It affects some more than others, and the triggers may vary. I've done races in high surf where some swimmers were actually vomiting into support boats and the water (yuck) but felt fine myself, but uniformly get vertigo in lakes if not wearing earplugs. For me the trigger appears to be cold water rather than wave motion; for others this may be different. If you manage to swallow large quantities of salt water, it can be nauseating. In one race, I ended up retching in T1. Then again, I can think of some lakes that might cause that, too!

*If you haven't done it before, swimming out toward open ocean is mentally hard. When I lived in Hawaii and first did this when body-surfing, I panicked, even though I'm a strong swimmer. It takes getting used to. Normally not an issue in shorter or multi-lap races, but you can get pretty far from shore in a one-lap Oly or Iron-distance swim.

*In both types of swims, but much more for ocean swims, I find the best strategy is to just focus on getting to the next buoy in a straight line at a decent pace, rather than thinking about too much else.

Hope this is useful!

Hmm

Waves and surf is more violent in the ocean, things can be choppy on big lakes, but in the ocean I had to sync my sighting to the waves in order to see the buoys. There are also more currents in the ocean.

Lakes can either be much colder if fed by melting water from nearby mountains, or much warmer because of low depth and still standing water. AFIAK ocean temperature is relatively more stable over the year.

Easier to find fix points for sighting in a lake, since they are all the way around.

The ocean is used as a dump, fortunately waste water is now cleaned most places and it dilutes more due to size. Local lake is easier to protect but depends on upstream rivers and things accumulate. Lakes are often more filled with algas making it a green soup, in the ocean you can actually see where you're swimming. 

It just feels different to swim in. Don't know if it's the salt and buoyancy but it's different. Salt irritates eyes, dryes your skin when you get out and tastes bad, but taking a sip replenish your electrolytes :P

Things that will like to eat you are surprisingly absent both in lakes and the ocean. The likelyhood of becoming shark dinner is infinitesimal, but look at the bright side, if that happens you will help saving an endangered species.

Lots of good stuff above, all true.

A lake swim will *feel* colder, even at the same temperature as the ocean.

Less chafing likely from wetsuit (or whatever you're swimming in, for that matter) in lake water.

CarlG - 2013-01-13 8:39 AM There is a huge difference.

Holy cow, if I saw that, I would just turnaround and call it a day. I was going to whine about the waves we dealt with yesterday at the Bone Island TRI where we had 20 mph winds and 3-4' waves, but that pales in comparison. That said, it was really hard to sight buoys and it wasn't a straightline course. The good thing was that, with the exception of swimming out against an incoming tide, we were going with the current. It is easy to get all in your head if you are not used to OWS, especially in the ocean, but if you have trained well, and go out for at least a few practice swims, you can get over that. I actually felt better yesterday with all the waves, etc., than I have in a long time in an OWS. Training was the key.

The biggest difference is the horrible taste. You quickly learn to exhale through your nose and keep your mouth clamped firmly shut!

Another difference is abrasion. You need a lot more lubricant to keep from being chafed raw where your swimsuit or anything else rubs. Get someone else to apply it if possible - the last thing you want is vaseline or other lubricants on your hands when you're trying to adjust your goggles. Your eyes will burn if you get the salt water in them, so make sure your goggles are right before you get in. If you're a guy, shave before swimming, you don't want stubble rubbing against your shoulders in salt water.

For some reason polyester suits are slightly more abrasive than those made of lycra.

Salt water feels a bit warmer for the same temperature, for some reason. Not sure why.

Besides the differences already mentioned, for me, I can get motion sickness in ocean waves.  It's rare that I do an ocean swim, but when I do, I take ginger pills to avoid chumming.

I've never done an ocean swim, but i have done some ocean swimming while on vacation.  I'm curious how the courses are typically set up.  Do they usually go straight out then turn and run parallel to the beach, or do they just head straight out and come back.  When I've practiced I've done the former and have been totally comfortable, since sighting is super easy since I can just look at the beach and as long as it's there I'm good.  But I could see it being a bit alarming to head straight out and come back.

Lake:

Stroke Stroke Breath Stroke Stroke Breath! (repeat as many times as u want) 

Ocean:

Stroke Stroke Water Stroke Breath Stroke trying Sight WhereTF am I? Stroke Stroke Wave WTF Breath

LOL