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. I would also recommend finding your maximum horsepower rating which is located on the yellow coast guard tag towards the back of your boat. You dont have to be a mathematician to determine the correct boat transom angle. So from there, I will try to help out by asking questions about your boat such as what type it is and the length. Assistant Measuring tape Grease pencil Ask a friend to hold one end of a measuring tape at the extreme outer edge of the top of the transom while you pull the tape across its width to the opposite outer edge to measure the "length of the taffrail," which is the width of the boat across the top edge of the stern. Boaters who consider going with a higher mount can see increased speeds. d.addEventListener("DOMContentLoaded", function (e) { Shaft lengths are available in increments of 5. When fighting waves from the stern, a 20-inch transom is considerably safer. loadScript(ptScript); Boats that use longer outboard shafts include: Make sure that you are measuring straight up, at a 90 degree angle to
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If your boat planes, pay extra attention to getting the shaft length as close to perfect as possible. It is where the outboard is mounted, and some boat owners place the name of the boat. Whether your on a pontoon boat, fishing boat, or speedboat boating is always one of the best times you can have. A deep Vee hull will result in a different measurement than a flatter . For slower boats, its less critical to. primeApr: 12.99, When trimming your motor, they provide you a greater bow response. This, however, is not recommended for the beginning boater. Place the point of a yardstick at the middle of the top of the boat transom. Mounting the outboard motor in accordance with the industry standards is important. var addy_textd53b59933f6c3f2e8b59f1b4a6d41fa5 = 'info' + '@' + 'vanssports' + '.' + 'com';document.getElementById('cloakd53b59933f6c3f2e8b59f1b4a6d41fa5').innerHTML += ''+addy_textd53b59933f6c3f2e8b59f1b4a6d41fa5+'<\/a>'; While this is the case there is certain saltwater motors that are extra extra long at 30. Depending on the manufacturer, size names might change. }) } }); })(document); A long shaft engine requires a height of 20 and extra-long shaft engines will need a transom height of 25. This alone can outweigh the negatives when deciding to adjust the mount upwards. (3) Move horizontally across the chart until you hit the graph curve. So its easier and safer to communicate with the dealer with the exact measurement of outboard shaft length in order to get the right model. Long shafts are 20-inches long. Finding the right size is a matter of looking at what youve got and taking out the measuring tape. A hydrofoil will typically level off the ride by driving the stern up and the bow down, and will stop or considerably minimize porposing on a 16 footer with a mid-sized outboard and no tabs, for example. If it measures between 17 and 22, you'll want to go with a long shaft motor. So how to measure outboard shaft length? However, you will need an understanding of how the degrees will alter the boats usability. *The Factors indicates the adjustment affected by on your boat type, the outboard working environment, and the transom distance as discussed above. Then finally test your outboard, if the mount is perfect. This is probably the worst case scenario out of the two. Step 2: Three Variables to Consider They keep water out of your prop and increase water pressure in the system. Basically, there are three main ways to measure motor height (that I'm aware of); probably the most common is: # 1: 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". Step 2 requires the propeller's radius (check the user manual and then the technical drawing). Check out the Westshore Marine & Leisure google plus page! Copyright 2017 Dealer Spike All Rights Reserved. https:/. This distance is very important to the performance of you boat. Many boat transoms are modified to use a different length of outboard by using a bracket. relation to pad
Anything bigger than that your obviously going to need an extra long shaft. When the right length motor is hung on the transom of a boat, the cavitation plate (the large plate that extends out over the propeller) should be even with the very bottom of the boat. This is the dimension you'll need when selecting a width for your outboard motor's mounting bracket. Now that you have a better understanding of boat transom heights its time to take out the ruler and get the perfect measurements. With this in mind, how can I determine if my outboard has a short or long shaft? With some boats I have a pretty good idea as to what length motor should be hung on them. #2. Boat transomangles play a pivotal role in the flexibility of the boats trimming abilities. As summer approaches there will be more boaters taking to the water. If you have a question or need additional information,contact ustoday. var h = d.getElementsByTagName("head"), This measurement would be the inches of
Smaller boats may use adjustable jack plates that can be changed to fit any outboard. ), and place it on the bottom of the pad in the center. #3. Measure from the top of the transom to the bottom of the hull. var path = 'hr' + 'ef' + '='; } There are 2 steps to help get a relatively accurate figure. Figuring out how to measure motor height on a
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Or it can have an angle degree as high as 30. All things considered, sticking with the industry standard is best for the beginner. Ask a friend to hold one end of a measuring tape at the extreme outer edge of the top of the transom while you pull the tape across its width to the opposite outer edge to measure the "length of the taffrail," which is the width of the boat across the top edge of the stern. Your goal is to measure how the outboard will sit, so start from the clamping plate and follow the centerline of the hull. the aluminum plate on top of the transom), to the bottom of the motor
If your boats transom height is 15-16, a short shaft engine is required, and if it is 20-21, a long shaft engine is required. But opting out of some of these cookies may affect your browsing experience. Increased RPM and additional horsepower feed the need for speed. mpeSelector: ".pt-mpe", The same is true for the newest, high-powered offshore fishing boats, where triple or quadruple motor setups are becoming more and more common. If measuring an existing outboard: Measure from the inside top of mounting bracket down to anti-cavitation plate above propeller (this is the largest plate/fin directly above the propeller). The outboard comes with mounting holes and brackets. If you are looking to repower, they may be able to offer some sage advice. When the boat transom is too low, the motor could end up underwater. Is my outboard long or short shaft? If you went too long it would still work but it may lack in performance. As mentioned above, the operation of the propeller relies on the transom height. Learn More About Your Boats Systems By Joining The Born Again Boating Academy! the propshaft below or above the pad. The propellers will also have trouble reaching the water. And the rule of thumb is that you should keep the cavitation plate level with the bottom or keel of the boat. Youll also want to pay attention when youre in shallow water because your prop will be lower than normal. 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. C Cheaptoon Cadet Joined Aug 4, 2010 Messages 28 Aug 24, 2010 #4 Re: Motor height on pontoon? Or measure from the main engine prop up to the water line? What types of boat need an extra long shaft? Where Onboard a Boat is the Transom Located and More About Transom Heights A propeller operates based on the height of the transom. When the jet drive is on the motor, set the height so that the leading edge of the intake is flush with the boat bottom. This was the height of my 225 Yamaha on my TR21
Doing this can have adverse effects. on How to Measure Outboard Shaft Length: The Only Guide You Need, ePropulsion vs Torqeedo: An All-Round Comparison, 55 lb Thrust Trolling Motors: All You Need to Know Before Purchase, Spot Lock Trolling Motor: Is It Worth It & Best Options in 2022, Wiring 24V Trolling Motors: 24 Volt Wiring Diagram (with Video), LiFePO4 Battery: Why Lithium iron Phosphate Batteries Are Your Best Options in 2022, Minn Kota vs MotorGuide: Best Option in 2022. If you decide to make adjustments, please consult a marine engine dealer about the boat design. All boats are different, and the motor manufacturers produce a variety of standard lengths. Expectedly, when the transom angle is zero, it means it is flat. What are Apple Podcasts Subscriptions and Channels? If your boat is newer and the manufacturer is still in business, you might also want to try to give them a call. This email address is being protected from spambots. s.setAttribute("src", script); var addyd53b59933f6c3f2e8b59f1b4a6d41fa5 = 'info' + '@'; Generally, short shaft outboards are 15 inches, long shaft outboards are 20 inches, and extra-long outboards are 25 inches. var xmlHttp = new XMLHttpRequest(); You
s.setAttribute("rel", "stylesheet"); If you have an outboard motor, the distance from one end to another will be found on the side or on a label near its bottom. Beefier jack plates can be fitted should a boater be looking to mount an outboard with a shorter shaft than their transom demands. How to Measure Transom Height For vessels with transom-mounted outboards, you can easily figure out which type of outboard you need to get. Other boats that need extra long shafts are: Read my other articles on outboard motors. Always weigh the risks of making adjustments. It is extremely important that the boater understands the significance of the transoms height. Step 4. Thats it. When mounting the engine, you want the cavitation plate to be 1 above the boat bottom for every 12 away from the transom. not sure that it's still used. Commonly, the transom angle ranges from 0-30 degrees, with the average transom angle set at 14 degrees. Keep these numbers in mind if you ever have a need for a new outboard motor for your boat. Engine Oil Type Genuine or Recommended 2str Engine Oil. Increased RPM and additional horsepower feed the need for speed. I also love helping others, which is why I created this website. and I'll explain it better, (or point you to someone that can help. 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. Pad to bottom of
At least if its too long you can raise the motor or "build up" your transom. While this is the case there is certain saltwater motors that are extra extra long at 30 and 35 shaft. While this is the case there is certain saltwater motors that are extra extra long at 30 and 35 shaft.