Project Overview

Problem Overview

The team's goal is to take the existing Perch submersible kit, and make it go as fast as possible. The team intends to accomplish this goal by modifying the propulsion, steering, and hull of the kit.

Design Constraints

• Needs to be fast.
• Has to be based off provided Perch submersible kit.
• Must be small.
• Affordable - sub $200 total budget
• Must be practical for a freshman design team to construct.
• Has to be completable in under 11 weeks.
• Has to be able to go up, down, left, right, forward, back.

Pre-Existing Solutions

How to propel a submarine is a well-understood engineering problem with many existing solutions.

Power

Diesel-Electric/Oil-Electric

• Marine diesel engines power electrical generators to charge batteries and/or power propellers. [3]
• Diesel or fuel-oil engine can only be run while submarine is surfaced or from air supply from snorkel.
• Batteries power electric motors while submarine is submerged. [3]

Nuclear

• Nuclear reactor powers steam turbine which in turn powers electrical engine to run propellers.
• Submarine can stay submerged for long periods of time without refueling. [2]
• Provides enormous amounts of power.
• Weight of reactor helps in making submarine neutrally buoyant.
• Nuclear power is environmentally friendly. [2]
• Regrettably, would be highly impractical to implement on a small-scale submersible for a freshman design project.

Electric 

• Batteries power electric motors on the submarine both while it is surfaced and while it is submerged. [2]
• Batteries can be located on the surface and power motors from tethered cable. [3]
• Probably the easiest to implement on a small-scale submersible.

Propeller  

• 2-4 blades on small ships [1]
• 4-7 blades on large ships  [1]
• All submarine blades are custom made-there are no standard designs or sizes  [1]
• Ship propellers are never perfectly straight or perfectly circular [1]
•  An odd number of blades reduces vibrations in the hull  [1]

Steering

Most of these solutions can be applied in concord with each other.

Control surfaces

• Many submarines use control surfaces similar to those on an airplane to move around. [2]
• Rudders (vertical and horizontal) are used to control the direction of water flow around the submarine

Ballast tanks

• Submarine ballast tanks are used to alter the buoyancy of the submarine, causing it to move up or down the water column. [1]
• Forward and aft trim tanks are used to control the pitch of the submarine

Thrust vectoring

• Actually changing the attitude of the propeller to alter the direction at which thrust is applied.
• Though undeniably effective, would likely be extremely difficult to implement.[1]

Hull Design 

Double-hull

• A double hull submarine has an outer (light) hull which is optimized for navigation, and an inner hull for withstanding pressure.
• This allows for maximum speed and maneuverability without compromising the ability to withstand pressure. [1]

Single hull

• A single hull submarine has only one hull, typically optimized for withstanding pressure.
• Though less complicated, such a design will never perform as well (as far as speed and maneuverability is concerned) as a double-hull submarine.[2]

No hull

• No hull, no watertight areas. Is very wet. Typical for unmanned submarines.
• The Perch kit, as constructed by default, is a no-hull design.
• No ability to withstand pressure, no consideration for fluid dynamics. Is generally awful.
• Acceptable for unmanned research submersibles which operate primarily in low pressure environments, for example, a submersible whose purpose is to monitor urine levels in the shallow end of the kiddie pool.

Design Goal

The team's primary goal is to create a submersible which can attain the highest speed possible. Secondary goals include improving maneuverability and increasing reliability, especially in the area of the propellers, which currently frequently fall off the supplied Perch kit.

Rough Draft Sketch of Seaperch

Project Deliverables

• The final speed of the submersible.
• New propeller design and placement
• New motor placement
• Improved hydrodynamics

Budget

Seaperch Kit: Free, provided by COE
Seaperch additional parts: Free, provided by COE
Additional Motor: $30
Aluminum: $10
Bolts: $5
3D printed parts: Free, provided by COE
Fishing Line/ cable / chain & gears for belt: $5-$20
Acrylic panels: $10
Arduino Board: $40
Misc: $20

Project Schedule

The deadlines that the team has to meet, along with all of our meeting times and planned milestones that we hope to achieve each week is located on our Google Calendar.