My Detailed Initial In-Water Impressions of Garmin Mk3i

[chrisjur]

I’ve never actually seen it myself, but I believe there are two levels of that alert. A Low Warning and a Critical Alert. This is true with all computers that are compatible with the PPS and Swift transmitters. The transmitter itself only sends three levels. This is imbedded in the data string sent. While Shearwater did develop their own transmitter, they also wanted to maintain compatibility, so I really don’t see that they had an option here as the data fields available would not allow real time percentages.

Some computers do allow you to check the transmitter battery level on demand. Others, like Shearwater include this information in the dive log.

According to the docs, in the same area where you would see “No Comms” (I think many have experienced this from time to time), you would see an alert that says “BATT. LOW”. This indicates that you have <20 hours of battery life left on the transmitter.

I also have never experienced this. I had about 50 dives on it before I changed the battery just as part of regular maintenance. My impression is that these transmitter batteries last very, very long.

 

[chrisjur]

I understand the concerns about the a potential situation where the Garmin transmitter coveys tank pressure topside using ANT, but there’s some sort of failure that stops it from transmitting via Subwave when you hit the water. But the reality is that the risk is low.

Has this ever happened? Possibly, but I’ve only heard “some guy once said” stories here on Scubaboard. And if it did, you would be aware of this quickly and have the ability to ascend.

Of course, most folks continue to carry a SPG in addition to AI, so that would relieve any concerns of single point of failure. And the likelihood of this type of failure, I’d guess, would be similar to the likelihood of any AI transmitter failing when you hit the water. So while the technical nature of the problem might be unique to Garmin, the risk is generic.

 

[Jai Bar]

I understand the concerns about the a potential situation where the Garmin transmitter coveys tank pressure topside using ANT, but there’s some sort of failure that stops it from transmitting via Subwave when you hit the water. But the reality is that the risk is low.

Has this ever happened? Possibly, but I’ve only heard “some guy once said” stories here on Scubaboard. And if it did, you would be aware of this quickly and have the ability to ascend.

Of course, most folks continue to carry a SPG in addition to AI, so that would relieve any concerns of single point of failure. And the likelihood of this type of failure, I’d guess, would be similar to the likelihood of any AI transmitter failing when you hit the water. So while the technical nature of the problem might be unique to Garmin, the risk is generic.

Yes, it can happen that the acoustic transmitter malfunctions. And sure, it is not the end of the world if one notices it on beginning of dive and/or has spg.


Would that happen to me when diving in the backyard back home, I wouldn't care so much. But in the middle of safari to Galapago, discover it once we have jumped in the water into the current?? Again, no biggie, not the end of the world- but definitely would piss me off if I had to abort such a precious dive because of such malfunction.

I would assume most divers prefer to know on the boat before the dive if something malfunctions.

 

[TheQuintessentialMan]

Excellent write up. Lot of good information and questions answered, at least for me.

I'm a EDC MK1 user. Connectivity with my employer's corporate health program gathering stats on workouts, steps, sleep, and other activities has pretty much paid for itself through the incentives HR offers; just throwing that out there. One of the features added to MK2 and enhanced with MK3 is the SPOx sensor. What I cannot find mentioned on the Garmin site is if that collects data while diving. Has anyone noticed if this feature active while diving? Another is the ECG app but no mention if it's compitable. Anyone?

The battery life of the MK1 is pretty good so would expect even better with MK3i. Originally I recall about two weeks if I didn't do any diving but as I've discovered more features and started tracking workouts and other activities, it needs charging once a week.

It was mentioned earlier that Shearwater and Garmin look like the future; I just recently got a Shearwater Peregrine TX to go with my MK1. My puck died and I like to have a back up. Too, the MK1 is getting more difficult to read without corrective lens. As much as I like the Peregrine, part of me wonders if I should have put the money towards the MK3i... but the Peregrine was about half as much and I can read it during a dive.

Until reading this thread, I was not aware MK3i could message between divers underwater. Anyone tested the range? Some of teh lakes we dive around here, that would be a good feature; just keep texting "where are you" back and fourth the whole dive... if only it could do direction for dive buddy.

Another feature I'm finding out about the MK is it's compatibility with InReach mini 2 sattellite communicator allowing sending a destress message from virtually anywhere on the planet with a clear view of the sky. Can also message cell phones; could contact the spouse while on a live aboard in middle of the ocean. You have to dig around the Garmin site a bit to find it but apparently there is a lot of interactivity and interconnectivity betwen select Garmin devices. There is another thread on the board about the InReach M2.

 

[spatty99]

Blood oxygen is not recorded underwater. It requires about a minute being very still to get a reading.​

​

ECG is not on the MK3, it was introduced as part of a new heart rate sensor in more recent Fenix/Epix models.​

​

The new transceiver can provide depth and distance from connected divers. So you could probably locate someone by getting to the same depth and swimming in a direction that reduces distance.​

​

I think I get a solid 3+ weeks on the MK3 51mm battery even with recording almost daily activities.​

 

[chrisjur]

I will add to my original post here as I continue to learn more and more about the Mk3i. It's been about eight months, and I now have about 100 dives using the MK3i, with its older sibling, the MK2i, as my backup computer. I continue to be very happy with MK3i and think it's a great dive computer. As I've used it more and more, there are a few things worth pointing out.

Dive Readiness Feature

As I originally mentioned, I do not wear the MK3i as a daily watch but only use it as a dive computer. However, on a recent 16-day trip to Honduras, I decided to wear it every day. In fact, I had read that the Dive Readiness "prediction" usually requires 2-3 days to collect data (including sleep time), so I started to wear it before I left for my trip. I have to say that this feature is very interesting. If you're unfamiliar, it provides you with a dive readiness "score" throughout the day, basing its prediction on all the metrics it's gathering about your body and health and your previous dives (it also gives you the reasons behind its score). Unfortunately, I did fall ill for a couple of days in Honduras, which impacted everything from my body temperature to my pulse/heart rate to my sleep schedule. The MK3i was right on top of this and suggested that I was not well enough to dive for two days - and rightfully so. Of course, the computer should not be the final arbiter on whether you should be diving or not, but it might give you a bit of a nudge if you're questioning yourself.

Garmin's platform also has a "Training Readiness" feature, which attempts to predict non-dive-related training readiness (e.g. cardio, weights, etc.). While the Dive Readiness feature does seem to take your Training Readiness into consideration, that doesn't seem to be the case the other way around. In other words, you might have just had two long dives and a low Dive Readiness score, but you might still have a high Training Readiness score. In fact, the Garmin will give you suggestions as to the types of exercise you should be doing to keep your body in shape. This, however, does not seem to take your diving history into consideration, and its advice flies in the face of prevalent research regarding vigorous exercise after diving. On days where I did two tec dives, the Garman was still saying that I'd be in great shape to start training. That is certainly not advice that I would follow.

Is this a huge deal? Probably not. I'm not sure how many people are actually using these features. But I thought it would be worth noting given that Garmin seems to trumpet this feature heavily in its marketing.


Multi-Gas Tec Diving

I should note that I have started using the MK3i (and MK2i) for multi-gas decompression dives. I have used it with one gas deco and two gas deco dives. The overall experience has been good, and there's nothing quirky to support regarding its behavior. The user screen and alerts are very clear when it comes to noting deco stops, deco times, gas switches, etc. Gas switching can be done with two pushes of a button. Alerts can be highly customized (they are a bit annoying out of the box).

There is one important issue that I'd like to recognize, however. The Garmin platform only allows for one global PO2 setting and does not allow you to set separate PO2 values for bottom time and for deco. As most tec divers know, there is typically a desire to set bottom PO2 to 1.4 and deco PO2 to 1.6 - this is not possible with the Garmin. So, this leaves you with a choice: Set the limit to 1.6 and be very careful about your bottom time PO2, or set it to 1.4 and be somewhat non-optimal from a deco perspective. (I'm oversimplifying this a bit, as the Garmin does allow you to set certain alerts and thresholds, so that if you set it to 1.6 max, it can start alerting you at 1.4. - check the user documentation)

There are several discussions about this on the Garmin forums: Feature request: Separate PO2 configs - Descent Mk3 Series - Wearables - Garmin Forums


Battery Performance Continues to be Excellent

After my Honduras trip, I've gotten a better sense of the MK3i battery life and can confirm that it is still pretty amazing. After a full charge, it is estimated that I have about 8 days of battery, and this is with the screen always on. In practice, I find that battery life holds true to those predictions, even when wearing it all day long and diving with it. There isn't a lot of battery "range anxiety" with this computer. You can wear it a few days without charging and be confident that it's not going to die on you underwater unless you're down to hours worth of batter life left (which, I've never actually seen). I found myself charging it up to 100% while I was in the shower every few days, and that was more than enough. I should note that I was also wearing it while I was sleeping.

T2 Transmitter and In-Water Messaging

I live in South Florida and see A LOT of these Garmin computers on boats, but I have never heard of anyone using the in-water messaging feature yet. Maybe it's gimmicky, maybe a bit ahead of its time, but it's just not something divers are using. If you are looking to save a few bucks on this already-expensive piece of equipment, you can still buy the T1 transmitter for $100 less than the T2. This will not allow you to perform two-way messaging, but it still works great with all air-integrated Garmin computers.

 

[Nick_Radov]

Multi-Gas Tec Diving

I should note that I have started using the MK3i (and MK2i) for multi-gas decompression dives. I have used it with one gas deco and two gas deco dives. The overall experience has been good, and there's nothing quirky to support regarding its behavior. The user screen and alerts are very clear when it comes to noting deco stops, deco times, gas switches, etc. Gas switching can be done with two pushes of a button.

Gas switching always seemed like the worst and most quirky feature of Garmin dive computers. When ascending it automatically prompts you to switch to deco gas as soon as it detects a safe PO2. The problem is that prompt covers the entire display so that you can't verify depth. This might be fine for cave diving, but when making a free drifting ascent in the ocean we need to verify that we're stabilized at the stop depth and cross check bottle labels against the depth gauge before actually switching. So I have to cancel the prompt first, then press buttons again to record the switch.

Have you found a way around this issue? There doesn't seem to be a way to disable that alert. Sometimes I wonder if the Garmin developers even do any tech diving?

 

[SKS22]

I will add to my original post here as I continue to learn more and more about the Mk3i. It's been about eight months, and I now have about 100 dives using the MK3i, with its older sibling, the MK2i, as my backup computer. I continue to be very happy with MK3i and think it's a great dive computer. As I've used it more and more, there are a few things worth pointing out.

Dive Readiness Feature

As I originally mentioned, I do not wear the MK3i as a daily watch but only use it as a dive computer. However, on a recent 16-day trip to Honduras, I decided to wear it every day. In fact, I had read that the Dive Readiness "prediction" usually requires 2-3 days to collect data (including sleep time), so I started to wear it before I left for my trip. I have to say that this feature is very interesting. If you're unfamiliar, it provides you with a dive readiness "score" throughout the day, basing its prediction on all the metrics it's gathering about your body and health and your previous dives (it also gives you the reasons behind its score). Unfortunately, I did fall ill for a couple of days in Honduras, which impacted everything from my body temperature to my pulse/heart rate to my sleep schedule. The MK3i was right on top of this and suggested that I was not well enough to dive for two days - and rightfully so. Of course, the computer should not be the final arbiter on whether you should be diving or not, but it might give you a bit of a nudge if you're questioning yourself.

Garmin's platform also has a "Training Readiness" feature, which attempts to predict non-dive-related training readiness (e.g. cardio, weights, etc.). While the Dive Readiness feature does seem to take your Training Readiness into consideration, that doesn't seem to be the case the other way around. In other words, you might have just had two long dives and a low Dive Readiness score, but you might still have a high Training Readiness score. In fact, the Garmin will give you suggestions as to the types of exercise you should be doing to keep your body in shape. This, however, does not seem to take your diving history into consideration, and its advice flies in the face of prevalent research regarding vigorous exercise after diving. On days where I did two tec dives, the Garman was still saying that I'd be in great shape to start training. That is certainly not advice that I would follow.

Is this a huge deal? Probably not. I'm not sure how many people are actually using these features. But I thought it would be worth noting given that Garmin seems to trumpet this feature heavily in its marketing.


Multi-Gas Tec Diving

I should note that I have started using the MK3i (and MK2i) for multi-gas decompression dives. I have used it with one gas deco and two gas deco dives. The overall experience has been good, and there's nothing quirky to support regarding its behavior. The user screen and alerts are very clear when it comes to noting deco stops, deco times, gas switches, etc. Gas switching can be done with two pushes of a button. Alerts can be highly customized (they are a bit annoying out of the box).

There is one important issue that I'd like to recognize, however. The Garmin platform only allows for one global PO2 setting and does not allow you to set separate PO2 values for bottom time and for deco. As most tec divers know, there is typically a desire to set bottom PO2 to 1.4 and deco PO2 to 1.6 - this is not possible with the Garmin. So, this leaves you with a choice: Set the limit to 1.6 and be very careful about your bottom time PO2, or set it to 1.4 and be somewhat non-optimal from a deco perspective. (I'm oversimplifying this a bit, as the Garmin does allow you to set certain alerts and thresholds, so that if you set it to 1.6 max, it can start alerting you at 1.4. - check the user documentation)

There are several discussions about this on the Garmin forums: Feature request: Separate PO2 configs - Descent Mk3 Series - Wearables - Garmin Forums


Battery Performance Continues to be Excellent

After my Honduras trip, I've gotten a better sense of the MK3i battery life and can confirm that it is still pretty amazing. After a full charge, it is estimated that I have about 8 days of battery, and this is with the screen always on. In practice, I find that battery life holds true to those predictions, even when wearing it all day long and diving with it. There isn't a lot of battery "range anxiety" with this computer. You can wear it a few days without charging and be confident that it's not going to die on you underwater unless you're down to hours worth of batter life left (which, I've never actually seen). I found myself charging it up to 100% while I was in the shower every few days, and that was more than enough. I should note that I was also wearing it while I was sleeping.

T2 Transmitter and In-Water Messaging

I live in South Florida and see A LOT of these Garmin computers on boats, but I have never heard of anyone using the in-water messaging feature yet. Maybe it's gimmicky, maybe a bit ahead of its time, but it's just not something divers are using. If you are looking to save a few bucks on this already-expensive piece of equipment, you can still buy the T1 transmitter for $100 less than the T2. This will not allow you to perform two-way messaging, but it still works great with all air-integrated Garmin computers.

Question: has your mk2i battery life degraded substantially over time? I have an mk2i and I only charge it to ~80% because I read on the internet that charging it all the way to 100% on a regular basis will wear out the battery prematurely. Years later my battery is like new, but of course I have no idea whether that's because I don't charge it beyond 80%, or whether it would have done just as well even if I was regularly charging it to 100%. As someone who charges to 100%, what have you observed?

 

[chrisjur]

Gas switching always seemed like the worst and most quirky feature of Garmin dive computers. When ascending it automatically prompts you to switch to deco gas as soon as it detects a safe PO2. The problem is that prompt covers the entire display so that you can't verify depth. This might be fine for cave diving, but when making a free drifting ascent in the ocean we need to verify that we're stabilized at the stop depth and cross check bottle labels against the depth gauge before actually switching. So I have to cancel the prompt first, then press buttons again to record the switch.

Have you found a way around this issue? There doesn't seem to be a way to disable that alert. Sometimes I wonder if the Garmin developers even do any tech diving?

Good point. I agree with you, it's clunky. I have not found a way around the issue. I believe if you leave it alone for a bit (not sure how long), the prompt eventually goes away (or am I just imagining that?). I'm generally too impatient for that and wind up canceling it.

But, as you rightly pointed out, it covers the whole screen while that alert is showing. This would be a good suggestion to Garmin for an enhancement/fix.

 

[chrisjur]

Question: has your mk2i battery life degraded substantially over time? I have an mk2i and I only charge it to ~80% because I read on the internet that charging it all the way to 100% on a regular basis will wear out the battery prematurely. Years later my battery is like new, but of course I have no idea whether that's because I don't charge it beyond 80%, or whether it would have done just as well even if I was regularly charging it to 100%. As someone who charges to 100%, what have you observed?

I have not noticed this with Mk2i. The battery still seems strong to me. I charged it to 100% yesterday morning, turned it on at 6am, did 2 dives, went home and turned it off at 5pm. Battery is still at 90+%.

To be fair, I ONLY use it as a backup dive computer, so the battery isn't getting a workout. I take it out the morning I'm going to dive and it gets put away 5 or 6 hours later.