316 Stainless Steel Boat Deck Drain - High-Flow Marine Scupper (50mm)
Deck-Plumbing-Hardware • Top Pick
Check PriceStanding water on a boat deck is a critical failure point. Inadequate drainage compromises deck integrity, increases slip hazards, and adds unnecessary weight to the vessel. Standard drainage systems often fail to manage high-volume wash-down or heavy precipitation, leading to pooling in the corners of the cockpit or gunwales. For offshore operations or high-spec coastal cruising, slow drainage is not an option.
Generic plastic scuppers and 304-grade steel alternatives are insufficient for long-term marine deployment. Plastic components suffer from UV-induced embrittlement, eventually cracking under foot traffic. 304 stainless steel, while initially cost-effective, lacks the chemical composition to withstand chloride pitting in high-salinity environments. When these components fail, the result is localized deck rot or bilge pump over-exertion. Maintaining vessel safety requires hardware that matches the technical demands of the environment.
The 316 Stainless Steel Boat Deck Drain - High-Flow Marine Scupper (50mm) is the engineered solution for rapid water evacuation. Precision-cast from 316 marine-grade alloy, this unit is designed for maximum hydraulic throughput and structural longevity. Unlike inferior components, this scupper utilizes a high-velocity 5-slat grille to optimize flow rates while preventing large debris from entering the drainage lines.
Performance Comparison: Marine-Grade Scuppers
| Metric | 316 Stainless High-Flow Scupper (50mm) | Generic Alternatives |
|---|---|---|
| Material | 316 Marine Stainless Steel | ABS Plastic / 304 Steel |
| UV Resistance | Immune to UV Degradation | High Vulnerability (Cracking) |
| Corrosion Resistance | Superior (Molybdenum Content) | Low (Chloride Pitting) |
| Service Life | Indefinite with basic maintenance | 12-24 Months |
Technical Specifications and Installation
This scupper is designed for a standard 50mm (approx. 2-inch) drainage aperture. The 78mm outer flange provides a broad sealing surface to ensure a watertight bond with the deck substrate. Proper installation is critical; use marine-grade sealant and ensure the sub-deck is clear of debris. For vessels requiring specialized drainage, consider the 316 Stainless Steel Self-Bailing Boat Floor Drain - Anti-Odor Scupper (1.5") for internal compartments, or the 38mm Boat Floor Deck Drain - 316 Stainless Steel Scupper (Mirror Polish) for smaller deck footprints.
System-wide hardware integrity must include intake systems as well. Ensure your cooling and utility lines are protected with the 316 Stainless Steel Boat Intake Strainer - High-Flow Thru-Hull Scoop (3/8" - 3"). For accurate positioning and vessel safety, always consult updated NOAA Marine Charts before major modifications to thru-hull or drainage locations.
Technical Glossary
- Chloride Pitting
- A localized form of corrosion that creates small, deep holes in metal surfaces, specifically targeting non-molybdenum alloys in saltwater environments.
- Molybdenum
- An essential alloying element in 316 stainless steel that enhances resistance to corrosion and high-temperature strength.
FAQ
- Will this drain rust in a saltwater environment?
- No. This drain is forged from premium 316 Marine-Grade Stainless Steel, which contains molybdenum for superior resistance to chloride pitting and saltwater corrosion compared to standard 304 steel.
- What size hole do I need to cut for installation?
- The drain is designed for a standard 50mm (approx. 2-inch) drainage opening. The outer flange measures 78mm to provide ample coverage and a secure seal against the deck surface.
- Does this drain prevent debris from clogging the bilge?
- Yes. The precision-engineered 5-slat grille acts as an integrated filtration system, capturing larger debris while maintaining a high-velocity water flow to keep your decks clear and safe.



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