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Yamaha Motor Size Formula:
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The Yamaha Boat Motor Size Formula calculates the maximum recommended horsepower for a boat based on its length and transom width. This formula helps ensure safe and efficient boat performance while adhering to manufacturer recommendations.
The calculator uses the Yamaha motor size formula:
Where:
Explanation: The formula calculates the maximum safe horsepower by multiplying the boat's length and width, subtracting 15, and then doubling the result to determine the optimal motor size.
Details: Proper motor sizing is crucial for boat safety, performance, and efficiency. An undersized motor may struggle to power the boat effectively, while an oversized motor can compromise stability and safety.
Tips: Enter boat length and transom width in feet. Measure the transom width at the stern where the motor will be mounted. All values must be positive numbers.
Q1: Why is there a subtraction of 15 in the formula?
A: The subtraction accounts for the basic structural requirements and provides a safety margin before the final horsepower calculation.
Q2: Is this formula specific to Yamaha motors only?
A: While developed by Yamaha, this formula provides a good general guideline for most outboard motor sizing, though always consult your boat manufacturer's specifications.
Q3: What if my calculated HP doesn't match available motor sizes?
A: Choose the closest available motor size below your calculated maximum. It's better to be slightly underpowered than to exceed safety limits.
Q4: Does boat weight affect motor sizing?
A: Yes, weight is an important factor. This formula provides a general guideline, but heavy boats may require additional power considerations.
Q5: Can I exceed the calculated maximum horsepower?
A: No, exceeding the calculated maximum can compromise boat stability, safety, and may violate coast guard regulations or warranty terms.