# CDT VN vs Tide Chart Master

The clearest difference is in-app purchases: CDT VN at none against Tide Chart Master's 8. CDT VN also leads on update cadence (every 2 days vs every 4 months). Tide Chart Master's advantage is iOS requirement (13.0 vs 15.5). On price, ads and device support there is nothing between them.

Both are free to download. Tide Chart Master sells 8 in-app purchases, starting at $0.99 per month. CDT VN asks for nothing beyond the download.

CDT VN ships an update every 2 days, Tide Chart Master every 4 months. The most recent releases landed on October 3, 2026 and September 24, 2026 respectively.

## The numbers

| Metric | CDT VN | Tide Chart Master |
| --- | --- | --- |
| Price | Free | Free |
| Rating | — | **[4.4 (7 ratings)](https://appshunter.io/ios/app/tide-chart-master/id6467185147/reviews)** |
| Number of ratings | — | **7** |
| Positive reviews | 15.4% of reviews | — |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | **Every 2 days** | Every 4 months |
| Monetization | **Free** | Subscription |
| Size | 71 MB | 36 MB |
| Requires iOS | 15.5 | **13.0** |
| Devices | **iPhone, iPad, iPod** | iPhone, iPod |
| Age rating | 17+ | 4+ |
| Developer | [GEOGRAPHY SOFTWARE JOINT STOCK COMPANY](https://appshunter.io/developer/1148381187) | [苗 何](https://appshunter.io/developer/1814015097) |

## What reviewers say

### CDT VN

[App page](https://appshunter.io/ios/app/cdt-vn/id1469180146)

This system helps fishermen manage their catch logs, transfers, and port permits. It also assists processing plants in obtaining origin certificates for seafood products and enables authorities to oversee fishing and export activities.

**Highlights:** Catch log management, Fishing transfer tracking, Port entry/exit permits, Seafood origin certificates, Fishing and export data management

**Features:** Vision Pro support

**In-app purchases:** none


### Tide Chart Master

[App page](https://appshunter.io/ios/app/tide-chart-master/id6467185147)

Access global tide charts with intuitive line graphs and 7-day weather forecasts. Includes tools for temperature, humidity, air quality, decibel detection, and a compass for navigation.

**Highlights:** Global tide chart viewing, 7-day weather forecast, Sunrise/sunset times, Temperature and humidity measurement, Air quality and decibel detection, Compass for direction

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases (8)**

| Purchase | Price | Billing |
| --- | --- | --- |
| 誉贺全球潮汐：订阅月度专业版高级服务 | $0.99 | per month |
| Tide Chart: Weekly Subscription | $0.99 | per 7 days |
| 誉贺全球潮汐：订阅月度高级专业版服务 | $2.99 | per month |
| 誉贺全球潮汐：订阅半年专业版高级服务 | $3.99 | per 6 months |
| Tide Chart: Weekly Subscription | $4.99 | per 7 days |
| 潮汐表：高级权限季度订阅 | $9.99 | per 3 months |
| 誉贺全球潮汐：订阅半年高级专业版服务 | $14.99 | per 6 months |
| Tide Chart: Quarterly Subscription | $24.99 | per 3 months |


## Frequently asked questions

### Is CDT VN free?

CDT VN is free to download, with no in-app purchases.

### Is Tide Chart Master free?

Tide Chart Master is free to download, with in-app purchases available.

### Do CDT VN or Tide Chart Master have ads?

Neither CDT VN nor Tide Chart Master shows ads.

### Which is updated more often, CDT VN or Tide Chart Master?

CDT VN ships an update every 2 days, and Tide Chart Master every 4 months. Most recently, CDT VN was updated on October 3, 2026 and Tide Chart Master on September 24, 2026.

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*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*