SF2 Rebreather Review

[JonTNY]

Finally I've had a chance to dive the SF2 rebreather in both back mount and side mount. Here's the story:

Back mount: IT'S AMAZING, clean, streamline, noticeably warm gas, Shearwater Divecan. The finish work and machining is every thing you'd expect to see on a mid to high end AMG. A few things really stand out:

1) The gas temperature, its warm, noticeably warm, I'm reasonably sure this will assist core temperature in cold water or those long boring hangs.

2) The trim: The unit sort of forces great trim, this is obviously an inherent benefit of the countering placement.

3) WOB is excellent, there's some talk about the unit being unmanageable in the vertical position (heads up or down), this is simply not true. Yes loading changes as it must but its unexpectedly comfortable and very easy to manage by isolating the DIL. Its intuitive.

Side mount:

Again WOB was excellent, stack a steel 02 bottle on the unit and pipe in DIL from you bail out is about as slick as its going to get. It is a little "busier" then a competitor and you can't put a sphere on the bottom of the unit because it would be to long and have a terrible effect on WOB (trapping the water would increase the exhalation effort well beyond any acceptable level, length would also be an issue) Accessing the 02 add is trouble free, the ADV handles DIL and it works well. I'm not sure how I feel about adding MAV's. I think I'd add a 2L steel to the unit and pipe in DIL from a LP120/85 and be done. No need to complicate things.

Its important to note that side mount rebreather issues are side mount rebreather issues and not SF2 issues. SM breathers are fickle and require time to fine tune to the individual.

The Dive Can boards are potted (no P2 like failures here) and batteries replaceable in 2 minutes or less.

In short this is one hell of a fine rebreather that took 15 minutes to set up on my first try with a checklist.

Cheers.

 

[The Chairman]

I'm glad I'm not the only one in love with this unit. I haven't turned mine into a sidemount unit yet, but I'm really close. A few more fittings and hoses and I'll be there. Then I'll have to figure out how to rig with two bottles.

 

[JonTNY]

I don't think its the right unit to try and build a self contained breather. I'd add 2-3 lbs to the unit to prevent the seesaw effect (but a steel bottle may handle most of that) and pipe in DIL from an 85 or 120.

I'd keep it as simple as possible and get the unit sitting and acting exactly how you want it to before worrying about MAV's, Needle valves or even BOV's. Stock and stripped first and when that perfect play with other ideas and options.

 

[victorzamora]

That's some intensely high praise, coming from you. If you had to recommend one SM breather, would this be it? Is it worth the price difference over the Sidekick?

 

[JonTNY]

That's some intensely high praise, coming from you. If you had to recommend one SM breather, would this be it? Is it worth the price difference over the Sidekick?

Vic, I was expecting something good but the unit is spectacular. The SF2 is a great (if not only) option for those looking for a convertible. Its the easiest eccr I've ever seen and dove, so if it was a tall brunette I'd have a wife.

To answer your question directly though (and to be fair) I don't have the experience necessary to make that call. I have a few ideas that I think would make the SF2 really nice in SM. I need to play with one more in SM. SM breathers are very fickle as you and I have discussed. If I have to bet it I'd say it makes one hell of a sm breather once its set up for the specific user.

As far as price goes the SF@ in BM ready to dive is about 10K, in SM its about 10,500 give or take, certainly not cheap. The KISS is 4500 stripped, a NERD is about 2000, hoses 200, 2 or 3 L Dil 300, Sphere if you go that route is 2000, 1st stages 500. So to trick the KISS out its virtually the same money. Granted there's much more wiggle room with the KISS but only to the true of maybe 2000USD so lets say the KISS is 8000? We haven't even discussed BOV's, DSV options, MAV's, Orafaces, IP pleasure fix's, etc.

The point is that I don't think the difference in price is enough to use that a a basis for anything given the fact that its life support. Both units work very well.

 

[tbone1004]

I think where he was going with that, is if you throw the solenoid away as a variable, would the SF2 be a ccr you would choose over your Sidekick despite the price difference? Or is the Sidekick 90% there, but at 75% the price, so the sidekick is a better value and while the SF2 is better, it isn't "better enough" to justify the extra money

 

[CptTightPants21]

I know you have dove a lot of different units.

Ignoring the SM convertibility factor, how would you rate it as a BM rebreather when compared to the other units..Revo, Meg, JJ, Hammerhead?

 

[JonTNY]

I think where he was going with that, is if you throw the solenoid away as a variable, would the SF2 be a ccr you would choose over your Sidekick despite the price difference? Or is the Sidekick 90% there, but at 75% the price, so the sidekick is a better value and while the SF2 is better, it isn't "better enough" to justify the extra money

Hi Tbone,

Its a good question but a tough one. To be honest I'd have to invest more time in the SM SF2 to create an answer that remotely credible. I really like my SK and spent time and money getting it close to perfect, I love the idea that its a true self contained SM breather but a few extremely well credentialed rebreather divers (with more experience then me) have argued against my "self contained" mantra. The arguments made are good ones. I do think discounting the solenoid would invoke a fair comparison. I like eccrs, in my opinion the solenoid is a +1 for the sf2, others feel differently. Sorry to be so long winded but I just can't render a valid opinion given my limited experience with the SF2 in SM.

Back mount units are much easier to build up or tear down in terms of appeal.

Cheers Tbone.

 

[JonTNY]

I know you have dove a lot of different units.

Ignoring the SM convertibility factor, how would you rate it as a BM rebreather when compared to the other units..Revo, Meg, JJ, Hammerhead?

Hi Capt.

To qualify my answer: I dove a JJ once 4+/- years ago at Ginnie, several improvements have been made since then.

With respect to the units you mentioned I wouldn't look further then the SF2 or MEG 15, there are other very good units around like the Optima.

Every unit you mentioned is solid (today), the SF2 and REVO stand out because they stray from the traditional "bucket" design. Both units have tight loops with fewer failure points the the others mentioned however 0-ring sealed static connections really aren't such a big deal today so I'm not sure how much of a factor that should be.

The MEG 15 is awesome, its well thought out and beautiful.

The SF2 is also awesome.

The JJ is a solid unit but I think that bad business decisions regarding its entry into the US market has handy capped the unit.

The REVO is/was my favorite but the company was sold, historically speaking thats never good for rebreathers.

The new Hammerhead or XCCR/defender is solid too but to be fair I haven't dove the new electronics just played with them and they are quite nice.

You can't go wrong with an SF2 or MEG 15, solid choices and both are on my soon to own list.

Hope this helps.

 

[toby43]

Finally I've had a chance to dive the SF2 rebreather in both back mount and side mount. Here's the story:

Back mount: IT'S AMAZING, clean, streamline, noticeably warm gas, Shearwater Divecan. The finish work and machining is every thing you'd expect to see on a mid to high end AMG. A few things really stand out:

1) The gas temperature, its warm, noticeably warm, I'm reasonably sure this will assist core temperature in cold water or those long boring hangs.

2) The trim: The unit sort of forces great trim, this is obviously an inherent benefit of the countering placement.

3) WOB is excellent, there's some talk about the unit being unmanageable in the vertical position (heads up or down), this is simply not true. Yes loading changes as it must but its unexpectedly comfortable and very easy to manage by isolating the DIL. Its intuitive.

Side mount:

Again WOB was excellent, stack a steel 02 bottle on the unit and pipe in DIL from you bail out is about as slick as its going to get. It is a little "busier" then a competitor and you can't put a sphere on the bottom of the unit because it would be to long and have a terrible effect on WOB (trapping the water would increase the exhalation effort well beyond any acceptable level, length would also be an issue) Accessing the 02 add is trouble free, the ADV handles DIL and it works well. I'm not sure how I feel about adding MAV's. I think I'd add a 2L steel to the unit and pipe in DIL from a LP120/85 and be done. No need to complicate things.

Its important to note that side mount rebreather issues are side mount rebreather issues and not SF2 issues. SM breathers are fickle and require time to fine tune to the individual.

The Dive Can boards are potted (no P2 like failures here) and batteries replaceable in 2 minutes or less.

In short this is one hell of a fine rebreather that took 15 minutes to set up on my first try with a checklist.

Cheers.

I had a look at the SF2 website, the can looks to be 600mm high which is pretty big. For travel purposes do you think it breaks down any smaller? It wouldn't fit in a normal big size suitcase at that height I dont think