Plane Crazy Submarine: How to Build and Control Submersibles

A submarine in the Roblox physics sandbox Plane Crazy is a naval vessel capable of alternating between cruising on the water surface and navigating fully submerged. Operating a functional submersible requires combining Ballast Tanks—which adjust buoyancy dynamically through keybinds—with fixed ballast weighting to stabilize your center of mass (COM) and prevent rolling.

Building an operational submarine ranges from compact unmanned surveillance drones to massive replicas like Typhoon-class vessels. Regardless of scale, mastering ballast configuration and underwater movement physics is essential before deploying your sub in peaceful roleplay or public PvP servers.

Core Blocks and Mechanics for Submarine Construction

Submersibles interact with Plane Crazy water physics differently than standard surface boats. Balancing negative and positive buoyancy relies on specific mechanical and propulsion parts:

According to community builder Turborover, Ballast Tanks are the single most important block for submersibles because their density can be directly shifted using assigned hotkeys. Meanwhile, Ballast Blocks allow builders to fine-tune deadweight, making them ideal for counterbalancing asymmetric parts or adjusting weight distribution without adding unnecessary volume.

Step-by-Step Submarine Build and Balance Guide

Constructing a stable submersible requires strict attention to the 51x51 base width and 39-block height workspace boundary, as well as proper center-of-mass alignment.

1. Shape the Outer Hull

Assemble your submarine hull using standard structural blocks, wedges, and half-wedges to create a streamlined bow and stern. Keep the interior hollow or designated for mechanical modules. If you plan to add custom angles or compact equipment, keep internal clearances open for ballast and mechanical components.

2. Distribute Ballast Tanks

Install Ballast Tanks evenly throughout the lower and middle sections of your hull. In community build testing documented on the Plane Crazy Wiki, having slightly too many ballast tanks is always better than having too few, as insufficient ballast will fail to drag the vessel below the surface. Leave default property values intact during initial placement.

3. Balance the Center of Mass (COM)

Submersibles frequently list to port (left) or starboard (right) once they enter the water. To stabilize the vessel:

• Place Ballast Beams directly below your center of mass.
• If one end or side continues to rise while submerged, place vertical jet engines or tiny upward thrusters on the rising section to maintain equilibrium without manual trim adjustments.
• Adjusting Ballast Beams by a single increment up or down will often eliminate unwanted rolling.

4. Install Propulsion and Controls

Map your forward and reverse propulsion blocks to convenient keys such as Shift and Ctrl or standard throttle bindings. While standard water propellers offer the cleanest performance in water, non-rocket and non-magnetic submersibles often struggle with low underwater velocities (frequently at or below 20 speed on standard setups). Adding supplementary concealed engines or rockets provides necessary underwater forward momentum.

Piloting and Depth Control

In Plane Crazy, a submarine generally needs forward momentum before diving or surfacing controls respond predictably. The vehicle uses dynamic water flow and ballast shifts together to alter depth.

Diving from the Surface

• Begin moving forward by engaging propulsion.
• Hold W to pitch the bow downward and initiate the dive.
• After holding W for approximately two seconds, press and hold F to flood or activate ballast control.
• As the sub approaches your target depth, hold S and release F.
• Make minor pitch adjustments using quick taps of W and S until the hull runs level.

Surfacing from the Deep

• Hold S to arrest forward dive momentum, releasing once forward thrust neutralizes.
• Hold R to dump ballast density (commonly referred to as blowing the ballast).
• The submarine will rapidly ascend and breach the surface.

Tactical Roles, Combat, and PvP Limitations

Submarines offer clear tactical strengths along with distinct vulnerabilities in multiplayer and combat scenarios:

Combat Advantages

• The Element of Surprise: Submerged vessels stay out of direct visual range of surface combatants.
• Countering Air and Melee Threats: Traveling below the water line neutralizes attacks from shredder bugs, flying jaw contraptions, and low-altitude aircraft that cannot enter the water safely.
• Under-Hull Strikes: Positioning your submarine directly beneath surface vessels such as battleships or destroyers lets you fire deck-mounted or upward-facing guns into their vulnerable keels where enemy return fire cannot reach.

Operational Disadvantages

• No Dedicated Torpedo Blocks: Plane Crazy does not feature a dedicated underwater torpedo weapon. Custom torpedoes must be constructed manually and require Ballast Blocks attached to them; otherwise, natural game buoyancy causes unweighted torpedoes to float straight up to the surface upon release.
• Vulnerability to Critical Damage: Submarines rely heavily on their Ballast Tanks, propulsion units, and internal seating. If enemy rockets or explosive blocks penetrate the hull, lost ballast blocks can render the craft completely unable to resurface or maneuver.
• Limited Underwater Visibility: Vision drops significantly beneath the surface, making external camera placement and careful navigation essential.

Frequently Asked Questions

Can you fire rockets while submerged in Plane Crazy?

Yes. Following game updates, rockets can be launched while submerged beneath the water. In earlier versions of the game, rockets would detonate instantly upon firing underwater, but current game physics allow them to deploy and strike targets.

Why do my custom torpedoes float straight to the surface?

Plane Crazy applies default buoyant physics to unweighted, detached builds. If you create a detachable torpedo bay using disconnectors, you must attach Ballast Blocks to the projectile to offset its positive buoyancy and keep it traveling horizontally underwater.

Why does my submarine constantly roll to one side?

Uneven weight distribution offsets your vehicle's center of mass. Add Ballast Beams along the lowest center point of your hull, or shift heavy functional parts until the COM aligns with the physical centerline.

What is the fastest propulsion method for water builds?

According to testing by experienced community builders, standard Water Propellers are the most efficient and least lag-inducing method for general water travel, edging out Water Propeller 2s slightly in top speed. For extreme speeds underwater, players incorporate hidden rocket engines or magnetic engine assemblies.