How To Determine Oar Size For A Drift Boat

Drift boat oars

A drift boat can turn on a dime and will immediately respond to even the slightest touch from the oarsman. But a drift boat will only perform at its best when you have the correct sized oars on it. Let’s look at how to pick the correct length of oar for your drift boat.

How To Determine How Long Your Drift Boat Oars Should Be

Drift boats are very popular fishing and river running vessels used mostly on turbulent inland waters.

Although a drift boat offers a lot of versatility by far its most beneficial feature is its maneuverability.

How long should a drift boat or be?

The easiest way to determine the correct oar length for your drift boat is use a simple boat-width to oar-length ratio.

For drift boats 60 inches wide use an 8 foot oar.

Increase the oar size by 1 foot for every 10 inch increase in boat width.

However, there is a simple 5 step formula you can use to more accurately size the oars for your specific drift boat.

Common drift boat oar lengths based on boat size

The easiest way to determine what length of oar you need for your drift boat you can use a simple ratio equation which I have included in the handy chart below

Drift boat oars

Below is a quick view chart for the common drift boat sizes with their preferred oar length.

Drift boat width (inches) Recommended oar length (feet)
60″ 8′ – 9′
70″ 9′ – 10′
80″ 10′ – 11′
90″ 11′

However, these are just generic measurements and you may find that you want an oar with a length that is much more suitable to your specific drift boat.

Luckily, there is a more accurate way of determining the optimal length of oar for a drift boat that involves a simple 5 step formula.

Below is a simple 5 step formula for working out the optimal oar length for your specific drift boat.

How to determine the correct oar length for your drift boat

To determine the correct length oar for your drift boat first measure the distance between the port and starboard oarlocks.

Take this measurement in inches.

This measurement is known as the span.

Once you have the span measurement, you take that number and apply the oar length formula to it that is  given below.

This will help you to determine which oar length provides the correct 7:18 leverage ratio.

The oar length you get from using this formula will mean you have an oar where 7/25 the length is inboard, of the oarlocks, and 18/25 of the oar length is outboard, of the oarlocks.

This is an ideal ratio that is used on almost every rowboat as it gives the optimal length for comfort, power and efficiency, especially when moving against the current.

Why oar length is important

Using oars that are the correct length is very important as rowing is a physically demanding activity.

Oar length is important when it comes to using any rowboat bit it is especially important when it comes to using a drift boat.

Although drift boats are versatile and extremely useful for a myriad of activities one of the most beneficial things a drift boat offers the rower is superior maneuverability.

The curved hull, flat bottom and pointed bow and transom make drift boats ideal for river running.

A drift boat can turn on a dime and is extremely responsive to the oarsman.

But, obviously if you are using the wrong sized oars these benefits are greatly diminished ad you will have less control over the vessel.

Wrong sized oars means loss of performance and greater fatigue to the oarsman.

Correct oar length will lead to correct rowing posture.

When you have the correctly sized oars you will be pulling directly towards your abdomen when rowing.

If you are not then your oars are probably the wrong size for your boat.

If you find that the oars tend to come out and away from the oarlocks when you row then the oars are likely much too short.

If you like to have an overlapping grip though you can add 6 inches to the calculated oar length.

5 Step Formula To Correctly Size Drift Boat Oars

Here is the simple formula for determining the correct length of oars for your drift.

Steps 1 – 5:

  1. Measure the span/distance between the oarlocks in inches.
  2. (Span / 2) + 2 = inboard loom length.
  3. Inboard loom length / 7 = final measurement.
  4. Final measurement x 25 = oar length in inches.
  5. Oar length in inches / 12 = oar length in feet.

Let’s look at these steps in this formula in more detail. They actually look much more complicated than they are.

Step. 1
The first step in the formula for determining the ideal oar length for your drift boat is as follows:

Measure the span between the oarlocks.

You will calculate the distance between the port oarlock and the starboard oarlock.

Make sure this measurement is taken in inches.

Measure the span.

Using a standard measuring tape measure the distance between the oarlocks on your drift boat.

Take the measurement in inches so the rest of the steps are easier.

Step. 2
Now you need to do a little bit of math.

You will use the following part of the formula:

(Span / 2) + 2 = inboard loom length in inches.

Take the measurement you made between the oarlocks (the span) and divide it by two.

Then add 2 to that number.

To show you this works we will look at an example of a drift boat that has a span of 48″.


After measuring between the oarlocks of your drift boat you get a distance of 48″.

So, using the above formula, in step 2, you divide that number by 2 and then add 2 onto it as follows:

48″ / 2 = 24″

24″ + 2 = 26″

So the measurement you end up with is 26″.

So our example drift boat has an inboard loom length of 26″.

Easy so far?!

Now let’s continue.

Step. 3
Take the inboard loom length number and divide it by 7.

So, the next part of the formula is:

Inboard loom length / 7 = final measurement.

In our example we have an inboard loom length of 26″.

So, as per the formula we will divide that by 7 as follows:

26″ / 7 = 3.714″.

We now have a final measurement of 3.714 inches.

Step. 4

We are almost done so hang in there.

Next we take the final measurement number and multiply it by 25 to get the actual ideal length of oar we need.

The next part of the formula is therefore:

Final measurement x 25 = oar length in inches.

In our example that means taking 3.714″ and multiplying it by 25 as follows:

3.714″ = 92.857″.

So the ideal oar length for a drift boat with a 48″ width/beam is 92.857 inches.

As oars are sold in feet rather than inches all we need do now is convert our ideal oar length from inches to feet.

Step. 5
Now you have the ideal oar length for your specific drift boat.

However, the measurement is in inches so you will want to convert it to feet as most oars are measured in feet.

As there are 12″ in a foot all you have to do to convert your measurement from inches to feet is to divide it by 12.

So, the final step in the formula is:

Oar length in inches / 12 = oar length in feet.

Of course you could just use an online inches to feet converter.

In our example we will take our oar length measurement, which is 92.857″, and divide it by 12 to get the oar length in feet.

This is:

92.8657″ /12 = 7.73 feet.

So the ideal oar length for our example drift boat with a 48″ width is 7.73 feet.

Rowing a drift boat

Unfortunately they don’t sell oars in quarter sizes so we need to get the closest oar length to our ideal oar length.

To do this simply roundup the number to the nearest foot.

In our example, we would roundup the 7.73 feet to get an optimal oar length of 8 feet.

Therefore for our example drift boat with a 48″ beam we would get two 8′ foot oars.

The table at the beginning of this post can help you make a quick buying decision when it comes to oar length. However, the formula given above will give you a much more accurate ideal length for the oars you use in a drift boat.

But not all humans are alike and what fits one person may not fit another that well.

The Key To Getting The Correct Oar Length Lies In “Comfort”

You should always feel comfortable when rowing.

When rowing your hands should be about 10 to 12 inches apart.

This space offers you the most efficient position for generating power from both your arms and your shoulders.

The rope warps on the oars should be positioned near the middle of the oarlocks though about a third either way is fine.

It’s all about comfort and power.

Having oars the wrong length can not only lead to inefficient rowing but it can also lead to unnecessary muscle strains.

Although the above information will go a long way to helping you choose the correct oar length there is no substitute for experience.

Get out on the water in a few different boats. If possible use a few different oars (with different lengths) on each boat to see which one feels the most comfortable for you and produces the best rowing results.

So when you go to buy a drift boat you now know what length of oars to buy with it.

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