Introduction to Building an 11 Foot Alutender RIB

Building your own 11 foot Alutender RIB (Rigid Inflatable Boat) is a rewarding project for boating enthusiasts and DIY aficionados alike. Combining the durability of aluminum with the stability and versatility of an inflatable collar, the Alutender design offers a lightweight, easy-to-handle boat perfect for fishing, leisure cruising, and tender use. Whether you’re a seasoned builder or trying your hand at boat construction for the first time, understanding the process of building an 11 foot Alutender RIB will equip you with the knowledge to create a reliable, seaworthy vessel tailored to your needs.

This detailed guide walks you through the essential steps, materials, plans, and tips to successfully build your own Alutender RIB. We’ll explore the benefits of aluminum as a boat-building material, discuss the structural design considerations, and provide expert advice on assembly and finishing. Plus, you can find comprehensive plans and resources to get started at build 11 foot Alutender rib.

Why Choose an 11 Foot Alutender RIB?

The 11 foot Alutender RIB is ideal for those who want a compact, maneuverable boat without sacrificing stability or durability. Here are some compelling reasons to consider building this boat:

Lightweight and Portable: The aluminum hull keeps the boat light enough for easy transport and launching.
Durable Construction: Aluminum resists corrosion and can withstand rougher marine conditions compared to traditional fiberglass.
Stability and Safety: The inflatable collar adds buoyancy and protects the hull, making it safer and more stable on the water.
Cost-Effective: Building your own boat saves money and lets you customize according to your preferences.
Versatile Uses: Perfect for fishing, diving, as a tender for larger vessels, or just casual boating.

Understanding the Alutender RIB Design

Basic Structure and Key Components

The Alutender RIB combines a rigid aluminum hull with inflatable tubes (collars) around the sides. This hybrid design offers excellent performance characteristics:

Aluminum Hull: Provides strength, rigidity, and impact resistance. Usually made of marine-grade aluminum sheets.
Inflatable Collar: Adds stability, absorbs shocks, and increases buoyancy. Typically constructed from durable PVC or Hypalon fabric.
Transom: Reinforced area at the stern to mount the outboard motor.
Frames and Stringers: Internal structural elements that support the hull and maintain its shape.

Dimensions and Specifications of an 11 Foot Alutender

The 11-foot length strikes a balance between compactness and usable space. Typical dimensions include:

Length Overall: 11 feet (3.35 meters)
Beam (Width): Approximately 5 feet (1.5 meters)
Draft: Shallow draft, often under 6 inches, enabling easy beaching and shallow water use
Weight: Usually between 100-150 lbs without motor or gear
Capacity: 2 to 4 persons depending on design and load

Materials and Tools Required

Aluminum Sheets and Tubing

Marine-grade aluminum, such as 5052 or 5086 alloy, is preferred due to its corrosion resistance and weldability. You’ll need sheets ranging from 1/8 inch to 3/16 inch thick for the hull and thicker aluminum tubing or angle for the frames and transom reinforcement.

Inflatable Collar Materials

Inflatable collars can be sourced as ready-made items or custom fabricated using materials like Hypalon or high-quality PVC. Hypalon is more durable and resistant to UV rays and abrasion but comes at a higher cost.

Fasteners and Sealants

Use stainless steel or anodized aluminum fasteners to avoid rusting. Marine-grade sealants and adhesives are critical for airtight inflatable tube bonding and for sealing welded joints to prevent leaks.

Tools

Welding equipment (TIG or MIG suitable for aluminum)
Sheet metal cutters and shears
Drill and bits
Riveting tools
Measuring tools and squares
Rubber mallet and clamps
Air compressor and pump for collar inflation

Step-by-Step Guide to Building Your 11 Foot Alutender RIB

Step 1: Acquire the Boat Plans

High-quality, precise plans are essential. You can find detailed and proven plans specifically for the 11 foot Alutender RIB at AluminumBoatPlans.com. These plans include templates, assembly instructions, and material lists to guide you through the build.

Step 2: Prepare the Aluminum Hull Pieces

Use the plans to mark and cut the aluminum sheets accurately for the hull bottom, sides, and transom. Use a metal shear or plasma cutter for clean cuts. Make sure to deburr the edges to ensure smooth welds.

Step 3: Fabricate the Frames and Stringers

Cut and shape aluminum tubing or angle stock to form internal frames that support the hull shape. Position these according to the blueprint to maintain the boat’s rigidity.

Step 4: Assemble the Hull

Weld the bottom plate to the side panels carefully, maintaining proper fit and alignment. Tack weld first, check for fit, then complete the full welds using TIG welding for the best finish and strength.

Step 5: Attach the Transom

Construct and weld the transom assembly, ensuring reinforcement where the outboard motor will mount. This section must be particularly sturdy to handle motor thrust and vibration.

Step 6: Install Internal Supports

Weld in the frames and stringers inside the hull, providing structural support and shape retention. Double-check measurements to maintain hull symmetry.

Step 7: Prepare and Attach the Inflatable Collar

Depending on your preference, you can order a custom inflatable collar or fabricate it yourself. Attach the collar to the hull by either adhesive bonding or mechanical fasteners through reinforced collars. Ensure airtight seals and proper inflation valves.

Step 8: Finishing Touches

Grind welds for a smooth finish.
Apply marine-grade paint or anodize the aluminum for additional corrosion protection.
Install seats, cleats, and any additional fittings according to your needs.
Test the inflation of the collar and check for leaks.

Tips and Best Practices for Building Your Alutender RIB

Follow the Plans Meticulously: Precision during cutting and welding ensures a well-balanced, seaworthy boat.
Use Quality Materials: Investing in good alloy sheets and durable inflatable materials will extend your boat’s lifespan.
Test Fit Components: Before welding, clamp and dry-fit components to avoid assembly mistakes.
Safety Gear: Always wear protective equipment when welding and handling tools.
Consult Experienced Builders: Online forums and builder communities can offer valuable insights and troubleshooting tips.

Maintenance and Care for Your Aluminum Alutender RIB

Proper maintenance will ensure your boat remains safe and functional for years. Aluminum requires periodic cleaning, especially after saltwater use, to prevent corrosion. The inflatable collar should be inspected regularly for punctures or leaks, and valve seals should be kept clean and lubricated.

Store the boat out of direct sunlight when possible to prolong the life of the inflatable tubes. Additionally, check all fasteners and welds annually to ensure structural integrity.

Conclusion

Building an 11 foot Alutender RIB is a fulfilling project that results in a versatile, durable, and lightweight boat designed for a variety of recreational uses. By following detailed plans and carefully selecting materials, you can create a vessel that combines the strength of aluminum with the safety and stability of an inflatable collar. Whether for fishing, tender use, or casual boating, the Alut