Hydrofoil Stabilizer Fins – Fits Outboard Motors Up to 50HP (4-50 HP) (Replaces Five Oceans FO-4470, SE Sport 300)
Hydrofoil Stabilizer Fins – Fits Outboard Motors Up to 50HP (4-50 HP) (Replaces Five Oceans FO-4470, SE Sport 300) is backordered and will ship as soon as it is back in stock.
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Worry-free returns
Worry-free returns
You may return most new, unopened items within 7 days of delivery for a full refund. We'll also pay the return shipping costs if the return is a result of our error (you received an incorrect or defective item, etc.).
You should expect to receive your refund within four weeks of giving your package to the return shipper, however, in many cases you will receive a refund more quickly. This time period includes the transit time for us to receive your return from the shipper (5 to 10 business days), the time it takes us to process your return once we receive it (3 to 5 business days), and the time it takes your bank to process our refund request (5 to 10 business days).
If you need to return an item, simply login to your account, view the order using the "Complete Orders" link under the My Account menu and click the Return Item(s) button. We'll notify you via e-mail of your refund once we've received and processed the returned item.
Delivery and Shipping
Delivery and Shipping
Free standard shipping on all orders under 1 KG
Hydrofoil Stabilizer Fins – Fits Outboard Motors Up to 50HP (4-50 H...
Product Details
These Hydrofoil Stabilizer Fins are designed to improve performance and stability for outboard motors ranging from 4 to 50 HP. Suitable for a wide variety of brands including Mercury, Yamaha, Evinrude, and Honda, they help boats get on plane faster and stay on plane at lower speeds. The two-piece design allows each foil to flex independently, absorbing shock and providing a smoother ride.
This part serves as a direct replacement for Five Oceans FO-4470 and can be used in similar applications as the SE Sport 300.
- Installs via a simple bolt-on process directly to the anti-ventilation plate (drilling required).
- Constructed from high-strength, UV-resistant black plastic for durability in marine environments.
- Kit includes all necessary stainless steel mounting hardware.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number | Notes |
|---|---|---|
| Five Oceans | FO-4470 | |
| SE Sport | 300 | For similar applications |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
| Brand | Model | Rated HP | Stroke |
|---|---|---|---|
| Mercury | Various | 4-50 HP | 2- & 4-Stroke |
| Mariner | Various | 4-50 HP | 2- & 4-Stroke |
| Yamaha | Various | 4-50 HP | 2- & 4-Stroke |
| Johnson | Various | 4-50 HP | 2- & 4-Stroke |
| Evinrude | Various | 4-50 HP | 2- & 4-Stroke |
| Honda | Various | 4-50 HP | 2- & 4-Stroke |
| Tohatsu | Various | 4-50 HP | 2- & 4-Stroke |
| Suzuki | Various | 4-50 HP | 2- & 4-Stroke |
Technical Specs
- Product Type
- Outboard Engine Hydrofoil Stabilizer Fins
- Installation
- Bolt-on (4 mounting holes)
- Connection
- Direct mount to anti-ventilation plate (cavitation plate)
- Housing Material
- High-strength black plastic, UV-resistant
- Housing Color
- Black
- Dimensions
- Approximately 180mm × 180mm per fin (7.1" × 7.1")
- Fitting Type
- 2-piece design (left and right wings)
- Warranty
- 1-year (Five Oceans model)
- Other Technical Attributes
- Molded in two unbreakable pieces, each foil designed to flex independently to absorb shock
What’s in the Box
- 1 x Hydrofoil Set (Left and Right Fin)
- 4 x Stainless Steel Screws
- 4 x Washers
- 4 x Pressure Nuts
Installation Notes
- Center the hydrofoil pieces on the anti-ventilation (cavitation) plate of your outboard motor.
- Mark the positions for the four mounting holes. Ensure they are clear of any underlying structures.
- Carefully drill the four marked holes through the plate using an appropriately sized drill bit.
- Place the fins onto the plate, aligning the holes.
- Insert the stainless steel screws with washers from the top and secure them from the bottom using the pressure nuts.
- Tighten all four nuts evenly and securely. Do not overtighten. Check for firmness before operating the vessel.
Troubleshooting & FAQ
Will these fins fit my specific outboard motor?
These hydrofoils are designed for a universal fit on most outboard motors from 4 to 50 HP. Installation requires drilling into the anti-ventilation plate. Always measure your plate to ensure the 180mm x 180mm fin dimensions will fit comfortably.
What performance benefits can I expect?
Hydrofoils can help reduce the time it takes to get on plane, maintain plane at lower speeds, and improve stability and tracking. Actual performance improvements vary depending on boat hull design, weight distribution, and engine mounting height.
How do these compare to the SE Sport 300?
These fins offer a similar function and universal fit for small-to-mid-size outboards. They are made from high-strength, UV-resistant plastic and feature a two-piece design that allows each wing to flex independently to absorb shock, similar to other popular models.
How often should I check the mounting hardware?
It is good practice to inspect the tightness of all mounting hardware (screws, nuts, washers) as part of your regular pre-launch checklist and at least once per season to ensure continued safe operation.
OEM vs. Aftermarket?
This listing is an aftermarket replacement (not OEM). It is built to OEM-level specifications with comparable materials. Manufactured in an ISO 9002 facility, it is batch-inspected for consistency.
Shipping speed & cost
We ship worldwide quickly—typical transit is 5–15 days. Standard shipping is free; expedited options appear at checkout where available.
Warranty & returns
Covered by a 1-year warranty against manufacturing defects under normal use. If issues arise, contact support with your order details. Returns are accepted within our standard window (unused & in original condition). See our policy page or reach out for instructions.
Safety & Important Info
- Verify images/specifications vs your original part. If anything differs—even if your model appears compatible—do not purchase.
- This is an aftermarket replacement, not an OEM component.
- Professional installation is recommended for safety and performance.
About Sea Sierra
- Pro-Grade Standards — We supply marine parts engineered to OEM-level tolerances and tested for real-world conditions.
- Fast Global Fulfillment — Free standard delivery to most regions in 5–15 days.
- Manufacturer-Direct Value — Fair pricing without compromising on materials or QC.
Payment & Security
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