How to measure transom height for outboard motor

Shaft length is simply the approximate transom height a given motor is designed to fit on. Measure the area of the transom directly where the engine will be mounted.

These attach to the transom where the motor mounts.

How to measure transom height for outboard motor. The buyer is supposed to be aware about the boat measurements as it helps in deciding the best transom height. For short shaft engines the transom height should be of 15 inches for long shaft the height should be of 20 inches and for extra-long shafts the transom height is supposed to be around 25 inches. Measuring For Correct Transom Height Measure down from the top of the transom bracket where it will sit on top of the boats transom to just immediately below the cavitation plate.

Some measurements are given from the top of the transom to the centre of the propeller and this will give you some idea of how far below the bottom of the keel you should have the. The height of the transom is calculated by measuring from the bottom of the hull to the top of the transom using the center line. On most newer center consoles and offshore boat transoms might include a rear door leading to a swim platform as.

How to Measure Transom Height. For vessels with transom-mounted outboards you can easily figure out which type of outboard you need to get. Measure from the top of the transom to the bottom of the hull.

Your goal is to measure how the outboard will sit so start from the clamping plate and follow the centerline of the hull. It is where the outboard is mounted and some boat owners place the name of the boatThe height of the transom is calculated by measuring from the bottom of the hull to the top of the transom using the center lineIt is extremely important that the boater understands the significance of the transoms heightThe height of the boat transom dictates the size of the. To sum up there is a simple calculator of the shaft length for outboard motors.

Outboard Shaft Length Transom Height - Factors. The Factors indicates the adjustment affected by on your boat type the outboard working environment and the transom distance as discussed above. Any owner seeking the last bit of speed from an outboard-powered boat should grab a yard stick.

Not to measure boat speed but to gauge the mounting height of the outboard motor on the boat transom. Rest the yard stick or another suitable straight edge along the keel on the bottom of the boat so that it makes a straight line aft to the outboard. Shaft length is simply the approximate transom height a given motor is designed to fit on.

It is NOT the distance measured from the mounting bracket to the cavitation plate AV plate. 20 shaft length motors will measure from 19 to 22-12 depending on brand and horsepower rating. Posted 04-28-2010 1131 AM ET US.

Basically there are three main ways to measure motor height that Im aware of. Probably the most common is. Height of the motor off the transom This is simply a measurement taken from the top of the transom top of the aluminum plate on top of the transom to the bottom of the motor brackets.

Hold the tape on the top center of the taffrail and measure straight down to the point usually a sharp angle where the transom joins the bottom of the boat. This is the dimension youll need to know when deciding between a short shaft long shaft or extra long shaft for your outboard motor. Manufacturer will recommend the outboard height according to the bracket shape and length.

As a yacht designer and boater I prefer longer shafts. It is unsafe to have the engine block too close to the water on a low transom. Plus a low transom.

The transom is a 20 inch. The factory rigged it. The motor sits up about 8 inches on a set of CMC vertical extensions.

The Yamaha specs call for 5 inches of vertical raise to mount the jet motor. Right now with the motor trimmed in all the way about half of the jet foot sits below the boat I put a level on the bottom of the boat to see this. My best estimate is its at least 2 under the water flow based on where the water hits the lower unit sides.

So today I took some measurements of the motor relative to the keel when both are level. One unexpected thing I found is my tilttrim indicator is a little over the 34 mark with the motor anti-ventilation plate level to the keel. How to measure boat for kicker motor length.

The cavitation plate should be at or just below the bottom of the transom. But if your kicker motor is mounted to the side of the main motor like everyones is wouldnt you want to be just at or below the transom where the kicker will be mounted which may be shallower than the center of the. Outboard Motor Shaft Length.

How do I measure. If mounting directly to a boat transom. Measure from the top of the transom down to the bottom of the hull or keel lowest point.

Measure the area of the transom directly where the engine will be mounted. This measurement is primarily designed for single motor propulsion. Its measured to where the motor mounts on the transom not to the notch.

When you buy a set-back bracket or lift plate they are sold in specific lengths 6 inch 12 inch etc. These attach to the transom where the motor mounts. If your rig needs more set-back then you measure what you have and add a bracket with more.

Just measure your boat from the top of the transom to the bottom of your boat to get the transom height. A 20 is considered to be a standard or long length. I guess you could use a different size shaft for your kicker motor.

But you would want to place your kicker mount where the cavitation plate is close to even with the bottom of your boat. The transom height needs to suit the outboard and ensure that the propeller will be in the correct depth of water in relation to the bottom of the boats keel. The height of the transom needs to let the cavitation plate just above the propeller sit below the bottom of the keel.

About 25 mm or so below the keel is usually about right but you might need to seek advice on. The transom is the back of the boat where the motor is hung. To do so you will want to measure at the exact center of the transom from the very top to the very bottom.

If it measures 15 or with in a inch of that you will need a short shaft outboard. The standard installation of an outboard has the top of the transom of the boat at the same level as the bottom of the motor portion of the outboard. One of the factors in determining the height of the outboard is the placement of the exhaust port on the lower unit of the outboard engine.

The outboard motor shaft length and transom length need to match in order for the motor to be at the right height while it is operating in the water. Short shafts are 15 to 19 inches long. Long shafts are 20 to 24 inches long.

Extra long shafts are 25 to 29 inches long and extra-extra long shafts are 30 inches and above.