Catamaran

Contains designs for parts of a composite catamaran TEK-45 (AKA Tektron 44) built by TEK-Composites in 1998.

Mostly made public as an example for other boat owners, to borrow ideas and designs from.

Seagull Striker

Originally made out of aluminum, later reverse-engineered and rebuilt out of prepreg carbon fiber and G-10 by GMT Composites.

Bracket

Originally made out of G-10 by GMT Composites.  The 2 screws to hold it in place are ¼"-20 x ¾".

References

• https://www.caeses.com/blog/2019/aerodynamic-shape-optimization-a-practical-guide/

Steering

The vessel has two steering wheels.

Components:

• helms
• roller chains
• stainless steel cables
• pulleys
• radiants
• bearing bushings
• rudders

Quite basic, yet very reliable and easy to maintain.

Helms

Two stainless steel helms by Edson Marine.  Each helm has a sprocket and 520 ANSI roller chain that translates rotating motion into push/pull force to the cables.

Radials

There're two radials, 400mm in diameter, 24mm thick.  There's a square cutout in the middle for rudder post, 50mm wide.  Each radiant has stops, mounted using bolts that go through its body.  Grove for stainless steel cable all the way around, metal corners where the cable bends.  Autopilot mounts for angle sensor and hydraulic actuator on starboard side.  The radials incorporate Ackermann steering geometry, meaning a slight offset to produce differential between two rudders when turned to either side.

Rudders

Two identical unsinkable carbon fiber foam core rudders.  Round post, square stainless steel mounting shaft (50mm).  There's a PTFE “washer” (spacer) between the top bushing and the radial.

Bushings

Two bushings per post, four in total for the entire system.  They “hug” stainless steel cylinders on the post, remain glued to the socket (hull).

References

• https://jefa.dk/products/rudder-blades/

Propulsion

Designs and models for mounting electric motor(s) to a boat's hull.

Originally the vessel featured two hydraulic motors connected to two hydraulic pumps, which in turn were both connected to one 55hp diesel engine.  The hydraulic motors were coupled with prop shafts using jointed stainless steel couplings “Big Boy” by Frontline Industries.

That old system was replaced by two 10kW BLDC motors, and the couplings were switched to magnetic by Mgt Solar.  Designs used for mounting those couplings to the new motors and old prop shafts can be found here: https://www.printables.com/model/1302452-magnetic-coupling

A transitory design file “Catamaran - Propulsion - Jointed Coupling” was designed and printed during malfunction of the non-flexible steel coupling supplied by the manufacturer of the electric motors.  The emergency happened on the Gulf side of Florida during trials in late 2023.

Motor

1 × 10kW, 48V, BLDC (terrible product, hence not listing the brand name)

Engine Mounts

4 × AMC Mecanocaucho, size small

Rails

2 × 2.5"x2.5"x2', ¼" thick, 6061 Aluminum

Supports

4 × 3D-printed supports

Holding Brackets

4 × Aluminum or 3D-printed L-brackets

Fasteners

• 8 × 3/8" (¾" long) bolts for engine mounts
• 8 × 5/16" (1" long) bolts for attaching holding brackets to rails
• 4 × 5/16" (2-½" long) bolts for attaching holding brackets to supports

Throttle Platform

Mounting the new throttle in place of old cable system posed a challenge, therefore “Catamaran - Propulsion - Dual Joystick Mounting Platform” was designed to serve as an adapter for the new dual lever marine throttle to be mounted without any hull modifications.

In case with Northern Bounty (Curious Cat), it replaced dual cable control by Morse.

The four screws needed are 10-24.  To mount the control unit itself will requires two short M6-1.0 bolts or screws.

Tips

• Leave extra space for couplings, ideally know dimensions of the couplings you're planning on using

Rigging

Tabs, mending plates, many other various parts related to standing and running rigging systems of a sailing catamaran.