Express Mach3 OS Propeller 15.6" x 15 – 3-Blade Stainless Steel, RH Rotation | High-HP Outboards
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Express Mach3 OS Propeller — 15.6" x 15, 3-Blade Stainless Steel, Right-Hand Rotation
The Express Mach3 OS is an extra-large-diameter 3-blade stainless steel propeller engineered specifically for high-horsepower applications where a standard-diameter prop simply can’t move enough water. Built from proprietary TP17™ stainless steel with refined cup geometry, improved leading and trailing edges, and an aggressive progressive rake, it delivers exceptional hole shot, impressive bow lift, and class-leading cornering for the largest outboard and sterndrive applications.
Best Use Case
The Mach3 OS in 15.6" x 15 pitch is purpose-built for large-horsepower bay boats, offshore center consoles, and high-horsepower pontoons and tri-toons where a larger blade sweep is needed to efficiently load the engine and move the hull. The 15-pitch is the lower end of the OS lineup — ideal for heavier hulls, fully loaded offshore rigs, and tri-toons where getting on plane quickly and maintaining speed under load are the priority. The large diameter also delivers strong mid-range fuel economy in many applications.
Key Features
- Extra-Large 15.6" Diameter — Larger blade sweep moves more water per revolution, loading the engine more efficiently on heavy hulls and high-horsepower applications where standard-diameter props fall short.
- TP17™ Proprietary Stainless Steel — 20% higher chromium content than standard stainless for superior corrosion resistance and a higher-gloss finish. Nearly 250% stronger and 5x more durable than conventional stainless steel alloys.
- MaxSpeed™ Dyno Balance — Precision dynamic balancing process ensures smooth, vibration-free operation at all speeds.
- Refined Blade Geometry — Improved cup, leading and trailing edges, and aggressive progressive rake deliver excellent hole shot, strong bow lift, and responsive cornering.
- Performance-Tuned Exhaust Vents — Optimized exhaust flow pathways reduce back-pressure and free up horsepower at wide-open throttle.
Specifications
- Part Number: 31511510
- Diameter x Pitch: 15.6" x 15"
- Blades: 3
- Material: TP17™ Stainless Steel
- Rotation: Right-Hand (Standard)
- Hub System: 500-Series hub kit (under 200hp) or 700-Series hub kit (200hp+) required — sold separately
Parts Desk Insights
Hub kit required — not included. This propeller uses either the 500-Series or 700-Series interchangeable hub system depending on your engine’s horsepower. Confirm your engine make, model, and year against the application chart to select the correct kit before ordering.
The 15-pitch is the lowest pitch in the Mach3 OS lineup — the right call for heavier hulls, loaded offshore rigs, and tri-toons where getting on plane quickly and maintaining speed under load are the priority. If your boat runs light and you want more top-end speed, step up to a 17 or 21-pitch. Browse the full Mach3 OS lineup:
Looking for a standard-diameter Mach3? Browse the Express Mach3 14.25 x 17 — 3-Blade SS, RH or Express Mach3 14.25 x 19 — 3-Blade SS, RH.
Shipping information
In-stock and OEM parts: ship same or next business day.
Locally warehoused items: ship within 3–4 business days.
Special-order items: timeline confirmed after order.
Returns & warranty
Returns & Satisfaction Guarantee
We stand firmly behind the quality of every product we sell. Your confidence matters to us — and we back it with a straightforward 30-Day Satisfaction Guarantee.
If you are not fully satisfied, you may request a return within 30 days of delivery. All returns must receive pre-approval prior to being sent back. Unauthorized returns will not be accepted.
To qualify for a return:
Item must be in new, unused condition
Product must be in its original packaging
All parts, components, hardware, manuals, and accessories must be included
Packaging must be undamaged and suitable for resale
Important:
Electronics are strictly inspected. No returns on open-box electronics. Exceptions may apply only with prior written approval. Any electronic unit that has been installed, powered, activated, or altered may not be eligible for return.
We are serious about product integrity — and equally serious about taking care of our customers. If there is ever a product issue, contact us immediately so we can make it right.
For return authorization, please contact our support team before shipping anything back.