To Shear’ or Not To Shear’ that is the question… Perdix, Teric, Nerd or Peregrine???

Lovin it, lovin it, lovin it… lovin it like that 🙂

The Shearwater Collection

After trying Suunto and Mares computers I should make it clear I am now a huuuge fan of the Shearwater Dive Computer and in my experience, the Perdix and Teric are the best dive computers in the market today.

I believe this strongly enough to have purchased a Perdix for myself and orientate my staff to use them also when possible, even blessing them with a Peregrine in relation to their excellent work ethic during certain periods of our season, plus we have the Petrel 2 for rent by our travel light tech divers as they are more durable when it comes to the hard to break surround… no one looks after equipment like we do our own so why no pre-empt a situation 🙂

The Petrel

The Nerd is the choice for the CCR diver and videographer…. the Perdix is the choice for any diver as the upgrades and versatility is tremendous.

Nerd 2

To show how the Nerd fits on to CCR or OC unit check out the picture below:

CCR & OC Fitting

Here is what sets Shearwater apart from other brands: 

Customizable algorithm, full features (trimix, Open Circuit, Closed Circuit), built-in compass, air integration, ability to handle more gas mixes than you are ever likely to use (5 in total), user changeable battery, upgradable firmware and a fantastic, legible display, all in a sturdy housing that is designed for extreme use (this is certainly no dainty wrist jewellery).

Perdix AI
Perdix AI

There is literally NOTHING you are missing in these dive computers.

Unfortunately, all this comes at a price and the at Perdix 950 euros (and its sibling, the Teric 1100 euros, or the Nerd at 1800 euros) are not cheap but worth every cent I assure you, plus the Shearwater Customer Service is bang on point 😊

The exceptional Teric wrist option, sleek and stylish

While there is definitely something to be said for having a computer that is virtually future-proof and that you are not likely to outgrow, the price of the higher end Shearwater does tend to put off people looking for a more value-priced computer.  

The add ons for the Perddix and the Teric is the AI… Air Integration option:

Only 280 euros from Alpha Divers, either in black or yellow 🙂


It also is an easy to play option with a user interchangeable battery to boot:

Transmitter battery, user replacement

But I have always been in the mind set ‘buy once, buy best… buy cheap buy thrice’. 

Enter the Shearwater Peregrine, it is an entry level dive computer intended to bring the Shearwater experience within reach to more people due to an easy to achieve price without getting grief from your partner for an overspend, at 520 euros it’s a snip when it comes to performance, visual ease and excellence related to your personal needs underwater, lush!

Let’s see how it fares!


I like the minimalist packaging that the computer comes in and it comes packaged in its own travel case, and inside, you find the following:

Everything that you need and no huge amount of wasted plastics and paper, at laaaaast, planet consideration.  

Kudos to Shearwater for a very eco-friendly packing job, few manufacturers consider this very important need to OUR World.

Note that while most units come with a black strap and a black bungee cord, you can get white or a matching blue rubber strap for the Shearwater Peregrine, if you so desire.

Various coloured straps are available for the Peregrine and never under-estimate the importance of colour in making sure you stand out amidst a sea of divers all dressed in black, personalise it baby!

Peregrine back view
The Peregrine


The Shearwater Peregrine is an over-sized dive computer and not a wrist-watch sized dive computer.        

As you can see below, the screen is approximately the same size as the Perdix, but the casing has been slimmed down a significant degree. 

Teric, Peregrine, Perdix and the Nerd
Left to Right, Teric, Pergrine, Perdix & the Nerd

The Perdix has a very strong – all business – look to it and this is a computer that is all business, all the time.  

The lines of the Peregrine are a little more relaxed, with a pop of colour in the form of the blue bezel around the screen (although that is the only colour available at present).

So why have I gone from a Suunto D9Tx, a watch-sized dive computer, to a Perdix, an oversized unit?

The key phrase is – all else being equal. 

In some cases, a larger dive watch is just an exercise in cost-cutting and miniaturization is expensive, after all.   In other cases, the larger form factors gets you more and better battery life, higher quality display, better presentation of information, etc.      

I am happy to say that the Peregrine, like its bigger brother, does utilize this large form factor very well.

A few things jump about the display.  

To start with, the legibility and ease of reading the info.   

This is a modern display with a high degree of contrast and easily legible in all conditions.  

Second, note the use of colours to highlight important information.   

Lastly and most importantly, notice how well the screen of computer displays information in an easy to read format.     

As an added bonus, you can even change the font colours as per your preferences.

One of the most common issues I have seen with divers is while they may be familiar with the – regular- screen of their computer, they often cannot read the decompression screen that comes up if they exceed their NDLs and the very information for which they bought the dive computer.


Bite the bullet and get the proper tool for the job… or why bother at all?

Shearwater’s experience with the needs of tech divers & now recreational divers awaiting their next Scuba Journey upgrade is clearly obvious here and the decompression information is clearly presented and cannot be confused with anything else.

It bears repeating and it doesn’t matter how high-tech your dive computer is:  

If it isn’t intuitive to understand, especially in a stressful situation, it is not a good option, think, think, think… ‘what do i want from my resource?’  

The Peregrine is aces in this regard, and for these tangible improvement, I am willing to forego the convenience of a watch-sized form factor (same as the Perdix).

In terms of ergonomics, the Peregrine, like the Perdix & Petrel 2, uses a 2 button interface but they are actual buttons, you can feel what happens.  

Better for those who like to actually feel what they are doing.

I initially expected this to be fairly clunky, given my experience with other 2-button dive computers, but the interface is surprisingly intuitive.   

It helps that Shearwater uses the display to give you very clear indications of what each button press is supposed to do.

The labels at the bottom of the screen tell you very clearly what each button press does and in this case, pressing the left button takes you to the next setting, while pressing the right button goes into planning mode.   

The logic is fairly intuitive and easy to pick up after a couple of uses. 

Note the green colour display and you can change font colours as well.

About the only downsize of this interface is that if you accidentally overshoot a setting, you have to scroll through the settings to get back to it.  

But the buttons are have a great tactile feel (the ones on the Peregrine are actually a lot nicer than the ones on my Perdix) and it takes all of 5-6 seconds to do this, so it isn’t really a great loss.


While the Shearwater Peregrine dive computer is an – entry level- model, it is certainly not lacking in features.

Peregrine Specifications
Specifications of the Peregrine

As you should expect from something carrying the Shearwater name, it is a full-featured computer designed for decompression diving.   

Unlike many of the entry-level dive computers designed for recreational diving which often tend to penalise divers significantly if they go into decompression. The Shearwater Peregrine will work well if you decide to get into extended range or technical diving. 

Of course, even if you accidentally go into decompression on a recreational dive, it will give you accurate information on how to handle your decompression safely.

Unlike its bigger brothers, the Perdix and Teric, the Peregrine does not offer trimix or closed circuit capabilities.  

However, the Peregrine dive computers also offers a 3-gas mix mode. 

This lets you use 3 different nitrox mixes:  typically a bottom gas and 2 different decompression mixes for accelerated deco.   

This makes it suitable for all air/nitrox based & technical diving.

For recreational diving, the Peregrine has the standard modes:  

Air, Nitrox and Guage Modes 😊

You have the option of setting both high and low PPO2 alarms, as well as depth and time alarms.  

One cool feature:  you also get a vibration mode, in case you are diving with a thick hood and unable to hear audible alarms. 

They think of everything!

The computer is based on the Buhlmann ZHL-16C:  the industry-standard algorithm, proven and refined over decades to offer the safest possible approach to decompression today.     

As is typical for most dive computers, you get 3 different conservatism settings and Low, Medium and High.      

Even at its lowest setting, the Peregrine is not excessively liberal and so this actually is a setting that may work for a lot of divers, depending on their preferences.

However, what sets the Peregrine apart is the ability to customize the GFLow / GFHigh percentages, if you so desire and this is a fantastic feature and is absolutely amazing to find it in this price range.

Do note that this feature is for experienced divers with an in-depth knowledge of decompression theory as well as their own personal risk tolerances and so I will advise not messing with it unless you are very sure you know what it does (hint:  if you have to ask someone what settings to use here, you are not ready to use it).  

When you are ready to use this feature, you will know how to set it, and you will be thankful you have had this feature.

In addition, the Peregrine also checks off my other vital criteria and a battery that is either rechargeable or user-replaceable.  

Unlike the Perdix, which uses a user-replaceable AA battery, the Peregrine offers wireless charging and place it on the provided USB platform and it charges.    

The charging platform is slightly smaller than the dive computer, so easy enough to pack and carry on a trip. 

For what it is worth, the Peregrine also seems to charge off the wireless charger I use for my mobile phone.

The Peregrine also has Bluetooth connectivity with Shearwater’s desktop or phone (Android/iOS) app, which lets you upload your dive logs to Shearwater’s cloud-based server and view them on the app.

The dive log on the Shearwater app shows you your profile as well as tissue loading at any time.   This log is from a Perdix, but the Peregrine information is very similar.

The app also allows you to upgrade your computer’s firmware.

Setting up a computer before the dive is very easy and it is a few buttons to adjust the nitrox and once you do, the nitrox percentage is clearly visible on your display.       

As with most computers these day, the Peregrine turns on automatically once you descend to about 1m of water.   And as discussed earlier, the display is super legible and easy to read.

The Shearwater display breaks up into 3 panels. 

The Pregrine

The upper left panel shows you the dive depth and time.   The upper right panel shows you decompression information (critically, the no-deco info and deco info are displayed in different locations, to prevent you from confusing the 2 numbers).    

And the smart use of colour coding highlights important information and whether you are running low on NDL .

The bottom panel can be customized as per your preferences. 

You can also get a visual display of your tissue loading, for each of the 16 compartments in the Buhlmann model and while this is typically not the most actionable of information.

I find it a very useful learning tool to correlate nitrogen loading from actual diving to the theory of decompression.   Seeing how the graph changes over the course of a diving vacation, or even after a shallow dive vs a deep dive can be very instructive.

The Shearwater also has a very easy to use dive planning mode and you can choose to plan your dive as if it were about to start immediately or after some time (eg, if you still had some more surface interval to complete), and figure out your NDLs accordingly.

And as mentioned, the solid, easy to press buttons make the entire experience of navigating the Shearwater Peregrine dive computer an absolute pleasure (users of the Suunto Zoop, for example, will know and appreciate what I mean!).  

Options for strap colours on the Teric apart from black are:

Teric strap choices

All in all, Shearwater are the way forward, available & always stocked:

Shearwater range
Shearwater Range