NSJ Tracker vs SailViewer
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
NSJ Tracker
Read full descriptionHide full description
GPS tracker app for yacht racing. Sends real-time position, speed, and course data to the race management server. ヨットレース用GPSトラッカーアプリ。位置・速度・針路データをリアルタイムでレース管理サーバーに送信します。
SailViewer
Read full descriptionHide full description
SailViewer turns sailing GPS and instrument logs into an interactive debrief on iPhone and iPad. Import a supported sailing file, choose the logs you want to open, and explore the race from several angles: • Track views with boats, courses, selections, and optional map backgrounds • Tables and graphs for comparing selected values • Polar analysis for speed and angle relationships • Start, Race, Boat, and Maneuvers views when supported by the data • Local image sharing from supported analysis windows SailViewer includes synthetic sample logs. Samples start closed, so you decide when to open them. You can import SW2, SLV, GPX, KML, NMEA, VTK, FIT, VKX, supported CSV sources, and supported ZIP archives. Your imported sailing files stay on your device unless you explicitly share them. Ordinary iPhones, including large iPhones, have permanently free local access and do not require weekly license checks. All iPads, including iPad mini, and this iPad app running on an Apple-silicon Mac are free through 31 December 2026. These devices require an internet connection for initial activation and at least once every seven days. Free access ends on 1 January 2027 at 00:00 UTC, when a paid subscription will be required. Purchasing will require a future app update; this release cannot take payments. There is no automatic charge. If access expires, your local library is retained. Optional error reports and usage summaries are off by default. Support reports are sent only when you choose to send them, and original sailing logs are not attached automatically. This is the new SailViewer app and is separate from the legacy SailViewer/TruSailViewer product. Automatic transfer from the legacy app is not promised; keep your original files and import supported formats into this app.
Screenshots
Verdict
The clearest difference is update cadence: NSJ Tracker at every 6 days against SailViewer's every 2 weeks. On price, ads, in-app purchases and device support there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
Both are free to download. Neither carries in-app purchases, so what you see is what you pay.
NSJ Tracker ships an update every 6 days, SailViewer every 2 weeks. The most recent releases landed on November 10, 2026 and November 7, 2026 respectively.
| Parameter | NSJ Tracker | SailViewer |
|---|---|---|
| Price | Free | Free |
| Update frequency | Every 6 days — better | Every 2 weeks |
| Ads | No | No |
| In-app purchases | No | No |
| Devices | iPhone | iPhone, iPad — better |
| Requires iOS | 17.6 | 17.0 — better |
| Further details — not scored | ||
| Size | 0 MB | 51 MB |
| Age rating | 4+ | 4+ |
| Developer | Keita Yukinori | Master Sailing jdoo |
In-app purchases
NSJ Tracker
No in-app purchases
SailViewer
No in-app purchases
Questions
Is NSJ Tracker free?
Is SailViewer free?
Do NSJ Tracker or SailViewer have ads?
Which is updated more often, NSJ Tracker or SailViewer?
Other comparisons















