Outboard Motor Shaft length for Pontoon Boat USA UK 2023

Outboard Motor Shaft length for Pontoon Boat USA UK 2023

Pontoon boats are recreational vessels that make for a great day outdoors with family and friends. They are also used as transport in some places to ferry passengers to and fro through lakes and rivers. 

For those who have the taste for it, they own one for fishing and adventure escapades. After all, pontoon boats have ample space to ferry for the family and can be customized for entertainment purposes as well. 

Pontoon boats, like most motorboats out there, propel forward on motor shafts. So many boaters end up asking themselves about the perfect outboard motor shaft length for their pontoon boats. Moreover, how do you measure it? 

We will answer all of these questions below!

What is an outboard motor?

Outboard motors are what propels the boat forward. It is a set of mechanisms that includes the engine, propeller, gearbox, jet drive, and steering capability. 

How should outboard motors be placed?

Outboard motors should be kept in a tilted position so that it does not scrape the bed when you are in shallow waters. Any damage could compromise the propeller and the motor itself. 

It should also be placed high enough so that no ventilation is caused which may reduce water pressure. The anti-ventilation plate should also be at least 2 inches above the keel. 

What should be the shaft length?

When purchasing an outboard motor, determining the shaft length is of prime importance. As a general rule, the length of the shaft depends on the power output of the engine of your pontoon boat. 

High-powered boats need shaft lengths of an extremely long size. 

The standard shaft length also depends on the size of the engine. Smaller the engine size, the smaller the shaft length you would need. 

The most common boats with standard engines require a 20-30 inches long shaft. This means that you may need extra-long or even extra-extra-long shafts for your barge. 

There are other factors as well which affect shaft length, as discussed below:

Factors affecting shaft length

To accurately ascertain the shaft length needed for your pontoon boat, just measure the distance between the water and the place where the motor would be mounted and add about 20 inches extra. You will have your ideal shaft length. 

However, you should also look at other factors like:

  • Type of boat

Shaft length would also depend on the type of transom and hull.

The speed of the boat is another factor. For slower boats, place the motor a little lower than the transom. For slow boats, prefer outboard motors with long shafts. 

For faster boats, the shaft length should be even more using the same formula as mentioned above.  

  • Motor placement

The correct placement for the motor would be the bow of the boat. This would require a longer shaft as the bow is higher than the rest of the boat. 

  • Space

For longer shafts, you would need to clear out space in the front of the boat. If you don’t have space, you may need to do some alterations to your floating vessel. 

However, if you don’t have space in the front, you can also place the shafts on the rear side of the boat. 

  • Motor type

For boaters who take their vessels to lakes or rivers can do with short shafts as compared to those who ride in open seas with big waves. If you are riding your boat in the sea or the ocean, you would need longer shafts. 

  • Other factors

Other factors are that longer shafts are more difficult to stick to a deck than shorter ones. Do remember this while purchasing shafts for your outboard motor of a pontoon boat. 

Short vs. Long Shafts

Outboard motors can be literally used in many types of boats, which is why they have been standardized by manufacturers. Ideally, a pontoon boat requires 15-30 inches of shaft length depending on output of power and purpose. 

Here is how shaft lengths are classified: 

  • 15 inch- Short Shaft
  • 20 inch- Long shaft
  • 25 inch- Extra-long shaft
  • 30 inch- Extra-extra long shaft

You can also find portable outboards up to 20 horsepower, which is available only in short and long shaft lengths. 

Getting the right outboard motor shaft length for your pontoon boat would ensure minimum drag and optimize the speed of your boat efficiently. 

Just remember that different pontoon boat sizes would require different shaft lengths. Most boats already have a place mounted beforehand so that you don’t have to worry about the placement. 

Additionally, if you are living somewhere off the coast and are interested in taking your barge to the open seas, it is strictly advisable to get a longer pontoon boat with a suitably longer outboard motor shaft length for smooth sailing in rough waves. 


Although most pontoon boats require long shaft lengths, it is always advisable to check beforehand and measure properly to optimize performance. To accurately ascertain the shaft length needed for your pontoon boat, just measure the distance between the water and the place where the motor would be mounted and add about 20 inches extra. You will have your ideal shaft length.
55-60" trolling motor shafts are the most common shaft size used for pontoon boats. For smaller boat sizes, you could even purchase a 48" shaft for proper functioning.
Ideally it won't. Short shaft lengths are meant for small fishing boats, while the larger ones are used for sailboats and pontoon boats specifically.
As a general rule, the outboard motor should be raised an inch for every 10 inches of the distance between prop and the transom.
Experts recommend a horse power of at least 115 kmph for a pontoon boat size of 25-25 foot range.

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