Pontoon boats are used in many countries as water ferries. They are used to transport people through rivers and lakes. It’s a fun way to get across a body of water and serves as a great outing as well.
For the boaters out there, you know that this boat is the perfect choice for families as well. This boat has space for those that like to lounge and enjoy the scenery while you go fishing.
To get the boat moving, you need a motor shaft. What is the perfect outboard motor shaft length for your pontoon boat? How to measure it? That’s our job to answer those questions for you. Get your gear ready and let us find out
What Is an Outboard Motor?
It’s a mechanism that gives thrust to the boat. It contains the engine, gearbox, propeller, and jet drive. It is placed outside of the transom and it’s most common with the small-sized boats. Not only does it give thrust but it also provides steering.
To remove hitting bottom with your motor, you can place it in a tilted position. This elevation especially helps with shallow waters. Since those waters might have some debris that could be damaging to both the motor and propeller.
Placement
The motor should be placed high enough without causing any ventilation that may reduce water pressure. This way, you’re minimizing the drag which will allow much better speed.
The anti-ventilation plate should be placed the same or maximum 2 inches higher than the keel (the bottom-most structure on a boat). The motor should be in neutral trim (angle the motor is placed in)
How Important Is the Length of the Shaft?
When choosing your shaft, length it’s very important. As each size depends on how powerful your boat’s engine is.
Standard Shaft Sizes
The shaft dimension depends on the size of the boat’s engine. If your boat has a small engine then you’d need a short shaft.
High powered boats would need shafts that are either long or extra long in length. Whereas a sailboat, for example, would need an extremely long shaft. It needs to be mounted higher off the water.
Most of the standard engined boats it takes shafts that are 15-30inches long. To break it down a bit more for you:
- Short shafts are 15-inches long
- Long shafts are 20-inches long
- Extra-long shafts are 25-inches long
- Extra-extra long shafts are 30-inches long
Depending on the manufacturer, size names might change. You’d find ‘standard size’ for example. If you’re not sure what those names mean, just pay attention to the size that is mentioned in the description of the shaft.
Choosing the Correct Shaft Length
Ideally, to measure the correct shaft length needed for your boat. You should measure the distance from where the motor will be mounted down to the water. Then you should add about 18-22 inches extra.
Boat Type
One of the factors is that it depends on the transom (the vertical part at the read of the boat) and boat hulls.
Another factor is if you have a slow boat or a fast one.
Slower Boats
It’s not important to have the exact location of the ventilation plate. It’s preferred to have it a little lower than the transom though. This way, it’ll keep the prop in the water when it gets in contact with the waves.
By default, it’s better to have a longer shafted outboard for this type of boats.
Faster Boats
For this type of boats, the size is essential. Having it an inch or two difference won’t cause a problem but that’s it! Getting the sizing correct optimizes the performance of the boat.
Other Factors
There are a few things you might want to consider as well when you are choosing the correct length for your boat:
The Placement
The most common location to place your motor is on the bow of the boat. Keep in mind though that placing it there would require you getting a slightly longer shaft. That is because the bow is higher than the rest of the boat.
The Clearance
Depending on how much space you have at the front of your boat. You need a clear space to place the shaft properly.
If you don’t there are some alterations you could do to your boat. They are inexpensive and actually common with most boat owners.
In case you don’t want to do any alterations to your boat, you can place the shaft at the rear of the boat. Which is a lower part of the boat and you’d need to get a shorter shaft length on the motor.
The Type of Water
If you are the type of person who usually goes out to lakes and rivers. You could get away with the short shafts.
Let’s say though you’re more into the larger bodies of water that have extreme waves. Then you’re required to get a longer shaft.
Getting a Shaft That’s Too Long
Generally, it’s much worse getting a short shaft than a longer one. The most common mistake made is getting a short one. Keep in mind that getting a too long of a shaft may be hectic when trying to stick to a deck.
Conclusion
Proper placement of your outboard motor will ensure that you don’t cause any drag and that you get the best speed your boat has to offer.
Keep in mind that different types of boats would need different sizes of outboard motors. Some boats will already have a place mounted for you. That way you won’t have to worry about the placement.
And if you’re interested in the open seas. Then it’s recommended that you get one of the bigger boats. Those were designed to sustain the waves that might damage the smaller ones.