Differences of Warm & Cold Water Diving

[Sas]

In your opinion, what are the largest differences that you've experienced between diving in warm water and cold?

Diving in warm water is incredibly easy - that's the biggest difference I found between that and cold/temperate water. I just dived in warm water for the first time last week and I just couldn't get over how easy it was. I was diving in 24C in a 3mm. The extra mobility and the reduction in weight made an enormous difference. I never had to think about buoyancy at all (I think my BC was a bit unnecessary as I barely touched it) and my air consumption was lower than normal.

How does this affect the type of diving you do?

In warm water it is easier to do longer dives, more of them, and feel less tired afterwards. Also I wouldn't get out of my wetsuit between dives. In cold water if I am in a wetsuit I get out of the suit asap and pile on tonnes of clothes to warm up.

How does this affect the diving equipment you use?

Different exposure protection and people in warm water seem to be more likely to use AL tanks... (anytime I go north I seem to only be able to get al tanks) Locally the temperature ranges between 9-22C. 15-22C I use a 7mm and <15C I use a drysuit.

Do you make any alteration to your decompression plan?

N/A to me. NDL dives I would not change anything other than sticking to my usual limits.

 

[Doc Harry]

In your opinion, what are the largest differences that you've experienced between diving in warm water and cold?

The largest difference is cumbersome cold-water gear. Getting everything on is a struggle, and the dry gloves makes it more difficult to manipulate things like valves and cameras.

How does this affect the type of diving you do?

How does this affect the diving equipment you use?

I chose the dive and then wear the appropriate exposure gear. The water temp doesn't directly influence my choice of dive. Sometimes I modify my gear for cold water. For instance, I add a thick cord to my wing dump valve so that I can find it easier with dry gloves. In really cold water I'll make sure that I carry some sort of redundancy in case I get a free-flow.

Do you make any alteration to your decompression plan?

Yes, I alter my deco plan in 4 ways:
-use a lower pO2 max, say 1.4 ata instead of 1.6 ata
-use thicker under garments in anticipation of a long deco
-plan deco stops using a depth 10 feet deeper my actual planned max depth
-limit the length of my dive to whatever time I feel that I can reasonably manage without getting cold

 

[gcbryan]

right on brother, you hit that nail right on the head. that other guy needs to pull his books back out and look at it again. just because the water is cold, the body is still warm and it takes time for the core temp to drop. this is some of the reasoning in ice diving. take a little more time to plan the dive and have some contingencies. conservative dives, slow asscents, and longer safety stops makes for safer cold water diving, not to mention staying hydrated.

It was a bit tongue in cheek, brother, although still true as far as it went. Most of my diving is in cold water.

 

[diverrex]

I've done roughly 100 dives in cold water (southern California cold: 54 in winter, up to 70 right now) and 100 dives in tropic warm waters. I am a better diver in warm water, better bouyancy and better SAC. I tend to do 3 dives a day here is So Cal in cold water because that's what our boats do while only doing 2 dives a day in warm water because then I'm with my warm-water-diving-only wife who is happy to stop after 2 morning dives. My gear is the same except for thermal protection. I dive year round in So Cal in 7 MM while usually only using a 3mm shortie in the tropics. I enjoy warm water with good viz dives much more than cold water dives but since we only have cold water off our coast that's what I dive here. I don't alter ascent rates or safety stops between the two, each depends on the particular profile.

 

[MauiScubaSteve]

Yes, I alter my deco plan in 4 ways:
-use a lower pO2 max, say 1.4 ata instead of 1.6 ata
-use thicker under garments in anticipation of a long deco
-plan deco stops using a depth 10 feet deeper my actual planned max depth
-limit the length of my dive to whatever time I feel that I can reasonably manage without getting cold

With regards to pO2 max; I've heard higher temps should have the lower pO2.

 

[Kevrumbo]

In warm water, my SAC rate is 30% better (i.e. less) than in the cold temperate waters here in SoCal. Deep dives that I normally do with big steel double LP104's here at home, I can use double AL80's instead when traveling/diving abroad & overseas in tropical SE Asia or the Caribbean. . .

 

[Walter]

Generally speaking warmer waters have better vis, generally.

Then why is the Gulf usually clearer in the winter when temps are much colder than in the summer?

Generally speaking, water temperature is not what affects visibility. What is the bottom composition? Is the water calm or rough? Is there run off from shore? Are there lots of tiny critters living in the water column? Does the water have tannin? These are the types of things that affect visibility. There are good conditions and bad conditions in both warm and cold water.

Diving in warm water is incredibly easy - that's the biggest difference I found between that and cold/temperate water.

Not necessarily. Is the warm water in a quarry? In the ocean with a screaming current and rough seas? Water temperature is not the biggest factor in what makes a dive easy or hard. Everything else being equal, it's easier to dive in warm water.

 

[DaleC]

Aside from all the other stuff mentioned I find that I approach rec diving in cold water from a more technical viewpoint. Almost every dive involves redundancy of some sort and more focussed dive/gas planning (not to say tropical divers don't however). I also think the light is different. 100' in tropical waters may "seem" relatively shallow where as 100' in cold water is usually quite dark. I think there may actually be more potential for harm in warm water due to people underestimating conditions.
Of course, as Walter points out, there are always exceptions to the rule.

 

[dannobee]

I know when we get the cold water spells, the vis usually goes UP. If the water temp here is below 48 deg, it's usually pretty clear-up to 100 ft vis. Warmer water brings the greenies out in force and the vis drops markedly.

Then why is the Gulf usually clearer in the winter when temps are much colder than in the summer?

Generally speaking, water temperature is not what affects visibility. What is the bottom composition? Is the water calm or rough? Is there run off from shore? Are there lots of tiny critters living in the water column? Does the water have tannin? These are the types of things that affect visibility. There are good conditions and bad conditions in both warm and cold water.



Not necessarily. Is the warm water in a quarry? In the ocean with a screaming current and rough seas? Water temperature is not the biggest factor in what makes a dive easy or hard. Everything else being equal, it's easier to dive in warm water.

 

[Doc Harry]

With regards to pO2 max; I've heard higher temps should have the lower pO2.

Other way around

EDIT: Let me re-phrase that. I've never heard about chosing a different pO2 max for warm water. But I have learned that it is prudent to select a lower pO2 max for cold water.