Attwood Marine Hydro-Stabilizer Hydrofoil Kit, Black Plastic, Stainless Steel Hardware

Overview

The Attwood Marine Hydro-Stabilizer is a bolt-on hydrofoil for outboards and stern drives that helps the boat climb onto plane more quickly, hold plane at lower RPM, and feel steadier through turns.

It mounts at the engine’s anti-ventilation plate and uses hydrofoil wings to add lift at the stern as speed builds. That can be useful on runabouts, fishing boats, tow-sport boats, and small cruisers that feel slow out of the hole, run bow-high, or lose grip during tight turns.

The range is split by engine size, with one version for 50 HP and above and one version for engines under 50 HP. Both versions use black molded plastic wings and include stainless steel bolts and lock nuts for installation.

Key features

• Helps the boat get on plane faster, which is useful when carrying passengers, gear, or pulling a skier from a stop.
• Helps keep the hull on plane at lower RPM, reducing the need to stay hard on the throttle once the boat is running level.
• Wing shape helps reduce ventilation in turns, giving the propeller a steadier bite during maneuvering.
• Made with black molded plastic wings for use around water and regular washdowns.
• Installs on a wide range of outboard and stern drive motors using the included stainless steel bolts and lock nuts.
• Available in two horsepower ranges so the stabilizer can be matched to smaller engines or 50 HP and above applications.

Variants

This Hydro-Stabilizer is offered in two configurations based on engine horsepower range.

The horsepower range is the key difference between the variants. The black molded plastic wing construction and included stainless steel mounting hardware are consistent across the range.

• 9400-7: Horsepower range 50 HP and above. This version is sized for larger outboards and stern drives where added stern lift can help the boat plane sooner and run with a more settled feel.
• 9401-7: Horsepower range under 50 HP. This version suits smaller outboards where planing speed, turn grip, and low-speed running attitude matter on light boats.

Installation and fit

Before installation, confirm the engine horsepower range and check the anti-ventilation plate for clear mounting space. The stabilizer is fastened with bolts and lock nuts, so alignment on the plate matters for a clean fit and balanced lift.

After mounting, run the boat through normal acceleration, cruising speed, and turns to check handling. Trim response can change after fitting a hydrofoil, so make small trim adjustments and note how the boat holds plane with passengers, fuel, and gear on board.

Use cases on board

This part is a practical match for boats that struggle to plane quickly, run bow-high during acceleration, or need better control while towing skiers or tubes. It is also useful for fishing boats and small cruisers that spend time at moderate speeds and benefit from staying on plane without excess throttle.

What’s included

• Hydro-Stabilizer wings
• Stainless steel bolts
• Lock nuts

Orders are processed within 2 business days, which includes verification, packing, and dispatch. Orders of $100 or more qualify for free shipping when eligible. For orders under $100, shipping costs are calculated at checkout based on destination, package weight, and selected service. International shipping is available for eligible products, and certain items may require additional handling, warehouse transfers, or may ship directly from the manufacturer, which can affect processing time.

Deliveries are handled by preferred carriers such as USPS, UPS, FedEx, DHL, and others depending on your location and selected service. Estimated delivery times are displayed at checkout and may vary due to customs processing, carrier delays, weather, postal disruptions, or other circumstances beyond our control. Once your order ships, you'll receive a confirmation email with tracking information. Tracking may take up to 24 hours to update on the carrier's website and is also available through your account when applicable.

We ship throughout the United States and to most international destinations for products eligible for international shipping. International orders may be subject to customs duties, taxes, brokerage charges, or other import fees, which are the customer's responsibility and are not included in the product or shipping price. PO Boxes are accepted only when shipping through USPS, and not all packages qualify for this option. If your order does not arrive within the estimated delivery window, please contact us at info@apollolighting.com or +1 (954) 375-0100 so we can assist with locating your package.

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Returns may be requested within 30 days of receiving your order. Items must be unused, uninstalled, unaltered, and returned in their original packaging with all tags, packing materials, blank warranty cards, manuals, instructions, accessories, and included items. Certain products, including installed or used electronics, electrical components, lighting, consumables, custom or special-order items, cut-to-length products, safety equipment, and merchandise exposed to water or marine conditions, may not be eligible for return.

To request a return, sign in to your account and select the applicable order and items, and submit your request for review. Eligible unfulfilled items may also be submitted for cancellation within 1 hour of placing the order. Returns or cancellations are not considered approved until you receive confirmation from Apollo Lighting. Please do not ship or drop off merchandise before receiving return approval and instructions.

Customers are responsible for arranging and paying for return shipping unless the return is due to an error by Apollo Lighting or the item is verified as defective, damaged, or incorrect. Missing, damaged, defective, or incorrect items must be reported within 2 business days of delivery, and photos or other documentation may be required for review. If the issue is verified, Apollo Lighting may provide or reimburse return shipping and issue a replacement or refund depending on the circumstances. International customers are responsible for return shipping, duties, taxes, customs charges, brokerage fees, and other costs associated with an international return.

After your return is received and inspected, approved refunds are issued to the original payment method and may take 5-7 business days to appear after processing. Original shipping and handling charges are nonrefundable, and the value of any included free items that are not returned may be deducted from the refund. Apollo Lighting does not charge a standard restocking fee on eligible returns. Returns that are incomplete, damaged, installed, used, altered, improperly packaged, or otherwise do not meet the eligibility requirements may be refused. We recommend using a trackable and appropriately insured shipping service for all customer-arranged returns.

For assistance, contact info@apollolighting.com or call +1 (954) 375-0100.

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Many products sold by Apollo Lighting include a manufacturer's warranty covering defects in materials or workmanship. Warranty terms vary by brand, product category, and model, so eligibility, coverage duration, exclusions, and available remedies are determined by the applicable manufacturer. We recommend reviewing the warranty information provided with your product before installation or use, especially for marine electronics, navigation equipment, lighting, electrical systems, pumps, safety equipment, and other specialized marine products.

If you need warranty service, the claim must follow the process established by the manufacturer, authorized service center, or designated warranty provider. You may be asked for proof of purchase, a serial number, product registration, photos, maintenance or installation records, or other documentation. Apollo Lighting does not determine or modify a manufacturer's warranty coverage or final claim decision, but we are happy to help provide purchase information and direct you to the appropriate manufacturer or warranty resource.

Keep your receipt, product documentation, serial number information, and original packaging when practical. Damage caused by normal wear, misuse, improper installation, insufficient maintenance, corrosion, impact, unauthorized modifications, electrical issues, or operation outside the manufacturer's specifications may not be covered. Warranty claims are separate from standard returns, so a product that has been installed, used, or exposed to marine conditions may no longer qualify for return while still remaining eligible for evaluation under the manufacturer's applicable warranty.

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