# Boat & Marine Engine Toolkit — Hull, Anchor & Prop Calcs

> Hull, Anchor & Prop Calcs (iPhone/iPad app by Shanghai Sheyuan Network Technology Co., Ltd..)

- Source: https://appshunter.io/ios/app/boat-and-marine-engine-toolkit/id6762048442 (this page in markdown: same URL + `.md`)
- Developer: [Shanghai Sheyuan Network Technology Co., Ltd.](https://appshunter.io/developer/1560626858)
- Category: Utilities, Productivity
- Price: Free with in-app purchases
- Age rating: 4+
- Requires: iOS 17.0 · 3 MB
- Languages: American English
- Released: 2026-04-15
- Data updated: 2026-09-03
- User reviews in markdown: https://appshunter.io/ios/app/boat-and-marine-engine-toolkit/id6762048442/reviews.md

## What is Boat & Marine Engine Toolkit?

Boat & Marine Engine Toolkit is a professional calculator suite for boat owners, marine engineers, naval architects, ship captains, and offshore platform crews. Run every calculation fully offline — at the dock, at anchor, or miles from the nearest cell tower. No ads, no accounts, no subscription.

From sizing ground tackle for a blow to checking prop shaft torque before sea trials, the toolkit puts trusted marine engineering formulas in your pocket and keeps them there.

WHAT'S INCLUDED:

Navigation & Anchoring
- Hull Speed Calculator — compute theoretical hull speed and speed/length (S/L) ratio from waterline length for sailboats, trawlers, and displacement craft.
- Anchor Chain Scope — plan rode length from water depth, bow height, and tide for safe overnight holding.
- Anchor Pull Strength — estimate working load on your anchor and rode from wind, current, and vessel windage.

Propulsion & Drivetrain
- Prop Shaft Torque — calculate shaft torque from engine horsepower and shaft RPM for gearbox and coupling sizing.
- Hydraulic Cylinder Force — push and pull force from bore, rod diameter, and system pressure for steering, hatch, and deck gear.
- Fuel Burn & Range — project fuel burn, cruising range, and reserve from tank capacity, GPH, and cruise speed in knots.

Safety & Compliance
- Bilge Pump Sizer — size pump capacity against hull volume with ABYC-aware guidance for peace of mind.
- Bollard Spacing — lay out dock and deck bollards with clean spacing for mooring lines and bollard pull loads.

Reference Tables
- Beaufort wind scale, anchor scope ratios, shackle working loads, and more — the numbers you actually reach for on deck.

WHO IS IT FOR:
- Boat owners planning passages, provisioning, and ground tackle
- Marine engineers sizing drivetrains, hydraulics, and auxiliaries
- Naval architects sanity-checking hull displacement and S/L figures
- Ship captains and mates running quick bridge calculations
- Offshore platform crews and workboat operators on deck
- Marine surveyors documenting condition and compliance notes

WHY MARINE PROS LOVE IT:
- 100% offline — every calculator runs on-device, so you never lose a tool when you lose signal offshore.
- No ads and no tracking — clean, focused screens built for use at sea.
- No subscription — pay once, own it, use it on every trip.
- Instant results — type values, get answers, move on to the next job on the checklist.
- Professional formulas — ABYC-aware guidance, standard naval architecture equations, and clear unit handling (knots, meters, feet, psi, bar, kW, HP).

ONE-TIME UNLOCK:
Unlock All Calculators is a single $19.99 USD in-app purchase. It is a one-time, non-consumable unlock — not a subscription. One payment opens every Pro calculator and every reference table, forever, on your Apple ID. Prop pitch planning, shaft torque, bilge pump sizing, bollard pull layouts, Beaufort references — all in.

Stow it in your pocket, keep it on the bridge, or pin it to the engine room iPad. Boat & Marine Engine Toolkit is built to be the quick, quiet answer to the everyday marine engine and offshore questions that keep boats running and crews safe.

## Pricing and in-app purchases

Base price: Free.

**One-time purchases**

| Purchase | Price | Type |
| --- | --- | --- |
| Unlock All Calculators | $12.99 | one-time |



## Version history (last 5 releases)

### 1.0.9 — 2026-07-26

New free reference: CG-719S Return Reasons. The sea service form is the most returned part of a mariner credential application — this lists what gets a CG-719S or sea service letter sent back, from a blank official number to the same month claimed on two vessels. Free for everyone, no purchase needed.

### 1.0.8 — 2026-07-01

Performance and reliability improvements.

### 1.0.7 — 2026-06-20

Pro unlock is now a one-time $12.99. Performance and stability improvements.

### 1.0.5 — 2026-05-15

Bug fixes and performance improvements.

### 1.0.4 — 2026-05-07

Bug fixes and performance improvements.

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All apps by Shanghai Sheyuan Network Technology Co., Ltd.: https://appshunter.io/developer/1560626858

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-09-03.*