Phone and watch, or a Vakaros? Choosing your start-line instrument
A $1,249 dedicated instrument and a phone in a bracket answer the same question — how far am I from the line? Where the hardware earns its price, and where it doesn't.
By the Sail Tactician teamUpdated 7 min read
We make Sail Tactician, one of the apps in this guide, so we have a stake in the answer. We don't accept free products or payment for placement, and we say where something else is the better buy. Details of other products are from their makers and retailers unless we say we've used them. How we write these
The short answer
Buy a dedicated instrument if…
you race a one-design fleet where starts are decided by a boat length, your class or regatta uses Vakaros RaceSense, or you want a 25 Hz line readout on the bulkhead that never needs a phone.
Use a phone and watch if…
you're club racing, learning to start, sailing more than one boat, or want the debrief afterwards without a second subscription — for a fraction of the price.
Or both
Plenty of racers start off a Vakaros and learn from the race on their phone. Vakaros VKX files import into Sail Tactician with the gun and both line ends.
Every serious one-design fleet now has a few boats with a small black box on the bulkhead counting down and reading out the distance to the line. The question we hear most from racers moving up: do I need one, or will my phone and watch do?
The instruments
The fleet standard
Vakaros Atlas 2
$1,249
The best start instrument you can mount on a boat — and the analysis lives somewhere else.
Dual-band GNSS at 25 Hz, a compass, gyro and accelerometer, a 4.4-inch sunlight-readable screen and around 100 hours of battery with wireless charging. It reads distance and time to the line, runs the start timer, and its LED bar can show time to burn or shifts. It also shows heel, trim and heading, and connects to the boat's NMEA 2000 network for wind and depth. The smaller Atlas Edge is $749. The free Vakaros Connect app sets it up and downloads its logs; for analysis, Vakaros points owners to third-party tools.
Per Vakaros and Practical Sailor. The Atlas 2 showed as sold out on Vakaros's site on 6 October 2026.
The long-standing alternative
Velocitek ProStart
$795
A focused start instrument with pacing cues — no companion app.
A countdown, distance to the line, and start pacing that tells you whether you're early or late through the last minute, plus heel and a compass. It logs your sailing to internal memory, which you copy off over USB and analyse elsewhere. Velocitek also makes the SpeedPuck and the Shift and Prism compasses.
Per Velocitek; older reviews quote $999 for the Gen 2.
What about Sailmon? Vakaros bought Sailmon in March 2025, and the Sailmon MAX is no longer sold — Sailmon's own site now points buyers to the Atlas 2. If you already own one, its tracks can still come into Sail Tactician as GPX.
The real difference: how often, and from where
Marketing talks about features, but the features are nearly the same: a countdown, two pings, distance to the line, time to burn. The real difference between a $1,249 instrument and your phone is two numbers.
How often it updates
A Vakaros reads its position 25 times a second. An Apple Watch, and most iPhones, deliver about once a second in practice. At six knots you cover three metres a second, so a once-a-second readout is always up to a second stale, and its distance to the line moves in steps rather than smoothly. In the last ten seconds, when you're deciding whether to hold or go, that's the difference between a number you can steer by and one you check.
Where it's measuring from
A bulkhead instrument is mounted on the boat, a known distance from the bow. A watch measures where your wrist is — wherever you happen to be sitting — and a phone in a pocket the same. On a dinghy that's a metre or two; on a 30-footer it can be most of the boat. A phone in a fixed bracket is much better than one in your pocket, because the offset to the bow stays the same.
What this means in practice: a phone or watch is good enough to know whether you're early, late or roughly on time, and by about how much. It is not good enough to sit a boat length off the line in a hot fleet and trust it to the metre. Keep a margin, or buy the instrument.
What each setup costs
Start line & burn
Update rate
Post-race analysis
Cost to start
Vakaros Atlas 2
Yes
25 Hz
Third-party tools
$1,249 (+ RaceSense $149/yr where used)
Velocitek ProStart
Yes, with pacing
Fast GPS; logs at 4 Hz
Third-party tools
$795
iPhone + Sail Tactician
Yes (Pro)
About 1 Hz
Built in
Free; Pro $29.99/yr. Plus a waterproof case and bracket
Apple Watch + Sail Tactician
Yes (Pro)
About 1 Hz
On the paired iPhone
Free; Pro $29.99/yr, if you own the watch
Instrument prices per the makers, 6 October 2026. Third-party analysis tools such as ChartedSails ($349/yr for Racer Pro) or Vantage Sailing ($99.99/yr) are extra.
Class rules and RaceSense
Check your class rules before you buy anything. Some one-design classes restrict which electronics you may carry or what they may display, and a phone running an app is still electronics.
The other way round, some fleets now expect a Vakaros. RaceSense lets the race committee broadcast both ends of the line to every boat, so timers start automatically and the instrument flags a boat over the line within about a second. It costs boats $149 a year or $50 an event. The Etchells class made it mandatory where race management uses it, which Scuttlebutt reported drew criticism in March 2026 over cost and access. If your fleet is heading that way, the decision may be made for you.
Sail Tactician has two features for restricted classes: a class-compliant lock that fixes the race screen to one page you've chosen, and Black Box, which shows nothing during the race but the clock while still recording everything for afterwards. It doesn't make any rules claim on your class's behalf — what's allowed is for your class and race committee to say.
After the race
The instruments are built for the start and the race. What happens afterwards is mostly someone else's job: Vakaros and Velocitek point their owners to analysis services such as ChartedSails, Vantage Sailing or Njord, which are separate subscriptions.
An app on your phone does both. Sail Tactician judges your start against the line you pinged before the gun — how far back you were at the gun, how fast you were going, how long it took to get up to speed — and its Coach ranks the rest of the race by the seconds it cost.
And if you own an instrument, you don't have to choose. Export your Vakaros session as VKX and Sail Tactician imports it with the gun, both line ends and the wind already set, so the start analysis works straight away. Velocitek logs convert to GPX with Velocitek's free converter, and Sailmon trips download as GPX. See bringing races in from other devices.
Where Sail Tactician fits
Most of the instrument, and the debrief
Mount an iPhone in a bracket and drive it from your Apple Watch, and you have a start-line display, a wind-shift readout, heel and trim, and a recorder — on hardware you already own. Starting the countdown on the watch starts the phone too, and the race is recorded once, with your heart rate from the watch. It won't match a 25 Hz instrument in the last ten seconds. It will tell you, afterwards, exactly what that start cost you.
Which to choose
Learning to start, or club racing: phone and watch. Learn what a good start feels like before spending $1,000 to measure it more finely.
A competitive one-design fleet: a Vakaros, especially if RaceSense is coming to your class. Import its logs into your phone for the debrief.
Several boats, or crewing for others: phone and watch — they come with you, and an instrument stays on its boat.
An older boat with no instruments at all: phone and watch. Beyond racing, Sail Tactician's Cruise mode makes a mounted iPhone a basic instrument panel — speed, heading, heel and trim — and logs every sail. See a sailing log and instrument panel for any boat.
A keelboat with instruments already: your existing system plus an analysis app; see the best sailing apps.
Questions
Is a phone accurate enough for distance to the line?
For knowing whether you're early or late and by roughly how much, yes. For holding a boat length off the line in the last seconds, no — a phone updates about once a second against a dedicated instrument's 25 times, and it measures from wherever it's mounted rather than the bow.
Can Sail Tactician read my Vakaros live?
No. Sail Tactician doesn't take live data from instruments. It imports a Vakaros session afterwards from its VKX file, including the gun and the start line.
Do I need a waterproof case to mount my iPhone?
Recent iPhones are water-resistant, but spray, salt and the odd knockdown are a different matter. A sealed case and a solid bracket are the sensible minimum on a racing boat.
Sources
vakaros.com and Practical Sailor's Atlas 2 profile; Vakaros Connect App Store listing. velocitek.com (ProStart, VTK converter) and the Melges ProStart Gen 2 review. sailmon.com/max ("no longer available"); Scuttlebutt, "Vakaros acquires Sailmon" (13 Mar 2025). Scuttlebutt, "Technology is hard to stop" (5 Mar 2026), on RaceSense and the Etchells class. chartedsails.com/pricing; Vantage Sailing App Store listing. Accessed 6 October 2026.
What changed
First published. Prices and specifications checked against makers' and retailers' sites.
Put a racing instrument on your wrist.
Start line, wind shifts and VMG at a glance, and a coach in your pocket afterwards. Free to download for Apple Watch and iPhone, with the full debrief on your first five races.
