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Questions and answers about sports

How long of a trolling motor shaft do I need?

6 min read

Asked by: Carolyn Morales

How long of a shaft does my trolling motor need?

How do I select trolling motor shaft length?

0″ – 10″ 30″
10″ – 16″ 36″
16″ – 20″ 42″
Over 22″ Consult Factory

Can your trolling motor shaft be too long?

However, if the shaft is too long, the propeller creates turbulence deep beneath the boat that will spook any nearby fish. And if the shaft is too short, the prop won’t be adequately submerged, which will create noisy chop in the water and also scare away the fish.

How long should a trolling motor shaft be on a canoe?

around 10-12″

Canoe Trolling Motor Ideal Shaft Length
To figure out the right shaft length trolling motor shaft for your canoe, measure the distance from where the motor mount is mounted across the bow or stern or from top of the transom to the waterline. on most canoes, this is around 10-12″.

How far below the hull should the prop be?

If you have a short shaft motor, the top most part of the transom and the lower most part of the boat should be about 15 to 16 inches. For a long shaft, I think 20 to 21 inches is correct. Some mornings it just doesn’t seem worth it to gnaw through the leather straps.

What size trolling motor do I need for a 16 foot boat?

If your boat is 16-foot or smaller, a high-thrust 12-volt model will be adequate for the conditions that you will face. If your boat is any longer, moving up to a 24- or 36-volt system is the only way to go for hassle-free boating.

How far below the water should a trolling motor be?


Submersion Rule: You’ll want the top of the motor submerged at LEAST 12″ under the water to ensure adequate power and to prevent noisy cavitation which will scare fish.

Can you shorten trolling motor shaft?

You can tighten it down a little bit further and that'll make it cut in a little bit deeper and what this does is it'll give us a really clean cut on our trolling motor.

How do I choose the right size trolling motor?

Boat weight is the most important consideration to take into account when choosing a trolling motor. A beginning rule of thumb is that you want a minimum of 2 lbs of thrust for every 100lbs. For example, if you have a 3000lb boat, fully loaded, then the calculation is (3000/100) * 2 = 60lbs of thrust.

How far below boat should cavitation plate?

The dealer set it at 1/2″ above the bottom of the hull when the motor is sitting level or straight up and down. When the motor is trimmed all the way down it is 1/2″ below the bottom of the boat but when trimmed up just a little there is slippage or some cavitation.

What happens if outboard is mounted too low?

An outboard that is mounted too low will limit your boat’s optimal operation. You can often tell that an outboard is too low if you are experiencing sluggish speeds, poor handling, excessive spray, porpoising, or even water pushing up into the cowling.

Do I need long shaft or short shaft outboard?

Measure from the top of your transom to the bottom of your keel. If it is from 15″ to 17″ long you’ll need to get a Tohatsu outboard with a “short” shaft. If it is from 20″ to 22″ long you’ll need our “long” shaft outboard.

Can I running a long shaft outboard on short transom?

Re: Longshaft motor on a short transom skiff? It will will *run* fine, but it can cause bad handling. Also trim position settings will have a greater effect.

What size motor do I need for a 20 foot fiberglass boat?

Tips for selecting the right size hp for portable outboard motor for your boat.

Motor HP Boat length (feet) Boat length (metres)
5hp – 15hp 8′ – 14′ up to 4.2m
9hp – 20hp 11′ – 16′ up to 4.5m
20hp – 40hp 13′ – 18′ up to 5.0m
40hp – 75hp 14′ – 20′ up to 5.5m

How do you determine shaft length on an outboard motor?

To measure your outboard motor shaft length, measure from the bottom of the mounting bracket where it rests on the transom to the top of the cavitation plate, this is the horizontal surface of the lower unit immediately above the propeller.

How do you measure shaft length?

A 48” golf club ruler is placed along the backside of the club with the tip of the rule touching the ground by the club’s heel. The final length is measured at the edge of the grip cap (and not the very top). This method is used in all cases except putters that the shaft is not located at the heel.

Can you convert a long shaft outboard to a short shaft?

If you change to a short drive shaft, you’ll need to change the other shaft that runs through the exhaust tunnel, as it will be too long as well — you’ll need to install a new, shorter shift rod.

What size outboard do I need for a 15 foot boat?

15 – 25 hp (36kg-52kg)

This hp range is quite popular for use with inflatable boats 10-14ft, aluminium fishing boats 12-16ft, jon boats 12-16ft in length, fibreglass boats 12-16ft in length.

What size motor can you put on a 14 foot jon boat?

Typical horsepower for a 14-foot jon boat would be between 15 HP and 20 HP although up to 25 HP is not uncommon either. 20 HP can comfortably give you a top speed of 20mph, potentially even stretching to 25mph depending on weather conditions and the weight on the boat.

How much horsepower does a 16 foot boat need?

To achieve maximum efficiency, you’ll have to give it 50 to 300 horsepower. There’s a range of the required power as you take into consideration the size and usage. An aluminum boat that is 16 feet long needs to have a 60 horsepower motor. Once equipped, it can have a speed of 25 to 30 miles per hour.

How big of a boat will a 9.9 push?

To answer the question posted “Best size aluminum boat for 9.9hp 2-stroke?” A 12ft would provide the best performance with a 9.9. If you want more boat space then a 14ft would be better but would perform best with a larger motor.

Why is 9.9 HP not 10 hp?

As you may have already noticed, many manufacturers supply 9.9 HP boat motors instead of 10 HP. There are good reasons behind those 9.9 HP motors: Some inland bodies of water have motor restrictions “under 10HP” only. Some states will require boat registration on boats with larger than 10 HP outboard motors.

How fast will a 14 foot jon boat go?

14 Foot Jon Boat Speed

You can expect 20-25mph out of your 14-footer. This boat length will generally allow for a 15-20hp engine, with some permitting up to 25hp motors.

How fast is a 4hp boat motor?

With the throttle all forward and with the waves pushing the stern, the boat planes and reaches a speed of 12 knots.

How fast is a 8hp outboard?

5 4 blade prop and manual JP tops out 20 to 21 mph. (6) 1436 G3 with 8hp merc tops out 16 to 18 mph. Alll flat-bottom jon boat runs skinny everywhere… canals, creeks, ponds, backlish water.

How fast does a Honda 5hp outboard go?

Had conditions been better, it is possible the Honda would have reached the 5-knot goal, however in our test it managed an average top speed of 4.9 knots. Acceleration was second best on test (behind the Yamaha), reaching its top speed of just under 5 knots in 5.29 seconds.