steel ruler, etc. Before we start measuring the outboard shaft length, lets get it clear about whats referring to when we talk about the outboard shaft length. Measure the area of the transom directly where the engine will be mounted. In step 3, add another 10 cm (4") to the previous calculation in order to develop the ideal shaft length. Say the 20 shaft is a long shaft length for gas engines, but it is a short shaft length for electric outboard motors. He is also a certified marine technician and the author of a popular text on writing local history. For example, you can have the Mercury outboard shaft length by model code. resting on the transom if you had the motor all the way down on the boat As you can see, the measurement is about 2 1/2". So if you are measuring the outboard shaft length for smaller boats, inflatables, dinghies, sailboat or other low-speed work boats, the cavitation plate is often about 2 below the bottom. LOYALHEARTDY Outboard Motor 6 HP 2-Stroke Inflatable Fishing Boat jackplate to a point level with the top of the transom. Boat Transom Heights - The Beginner's Guide | My Westshore If you have already measured you transom tip to bottom to be 20", then if you place aux sdieways to central engine your available transom height will be probably 1"-1.5" " higher and work perfecty. 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. When measuring the transom height, you should start from the hull's bottom at the boat's center line up to the top of the transom. Another important measurement is the transom angle. A long shaft engine requires a height of 20 and extra-long shaft engines will need a transom height of 25. since 1986. Top 10 Choices for Boaters, Mercury Introduces 600HP V12 Verado Outboard Engine, The Outboard Expert: Tohatsu Propane Outboard Engine. There The vertical distance between the interior of the clamp and the cavitation plate is the shaft length specified by the outboard manufacturer. This alone can outweigh the negatives when deciding to adjust the mount upwards. As a result, the issue is whether my boat need a short shaft or long shaft motor. Disclaimer: As an affiliate I may earn a commission on any qualifying purchases, including those from Amazon.com, at no extra cost to you read more. hulls, such as Allisons, Bullets, Strokers, etc., this measurement could PayTomorrow.mpeInit({ 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). 7. Other uncategorized cookies are those that are being analyzed and have not been classified into a category as yet. The average transom angle is around 14 degrees. ), and place it on the bottom of the pad in the center. Get the latest updates on new products and upcoming sales, 2023 Marine Parts Warehouse Incorporated endobj Boats with more engine power and weight require longer shaft outboards for better balance. Your email address will not be published. Check the literature about your model boat online, and you may be surprised to find that the number is published for you. However, there may be times when a boater strays away from these recommendations. Your at your local outboard dealer shopping for a new motor and the salesman hits you with the question, "short or long shaft?". You can find your Mercury outboard model code on an ID plate or sticker. want to measure from the transom to the flat part of this bracket, Here are several situations on how you should adjust the outboard shaft length: Mounting the outboard a little bit higher than the standard point could reduce drag, improve RPM at full throttle, and therefore improve speed and make it easier for the boat to get on plane. This distance is very important to the performance of you boat. Lastly, knowing the year of your motor and what style of controls you have (side mount, concealed side mount, or binnacle) is also a plus because it will tell the dealer if your current controls are compatible with the motor you are purchasing. In lower mounting, the engine is set lower than the recommended standard. These cookies track visitors across websites and collect information to provide customized ads. This could also affect your travelling capabilities on the boat trailer. Thats it. The anti-cavitation plate above the prop needs to be within an inch of the bottom of the transom, therefore, the prop should be well below the transom. A: The short answer is Yes. Other boats that need extra long shafts are: Read my other articles on outboard motors. To do so, you will want to measure at the exact center of the transom from the very top to the very bottom. Doing this can have adverse effects. How To Mount An Outboard Motor Properly - Start to Finish! The cookie is used to store the user consent for the cookies in the category "Other. If it measures anywhere from 17" to around 22", then your going to want to go with a long shaft motor. If the height of the boat transom is off it can cause major issues. logoColor: "original", Yamaha Outboard Motors: How To Measure Leg Length Whether you already own a boat or looking for your first watercraft we are here to service your needs. With some boats I have a pretty good idea as to what length motor should be hung on them. Will Charpentier is a writer who specializes in boating and maritime subjects. The transom is the flat vertical section at the rear of the boat. How to Measure a Boat Transom - Gone Outdoors This is probably the worst case scenario out of the two. 2019s List of the Best Recreational Pontoon Boats for Sale. It is extremely important that the boater understands the significance of the transoms height. You can use a longer shaft than recommended and your boat will work fine. The how to measure the shaft length of an outboard motor is a question that many people have asked. Follow Westshore Marine & Leisure on Twitter! The motor length corresponds to the transom height of the boat, measured from the keel to gunwale at the transom. According to MarinePartsMan.com, the outboard can be raised 1 inch above the standard height for every 10 miles per hour of speed the boat can attain. Triton. Follow Westshore Marine & Leisure on Wordpress! These allow the mounting of a standard length outboard behind the transom. However, with the outboard shaft length too short, meaning the prop is too close to the surface, the engine is likely to ventilate and therefore slip on acceleration or lose power. However, the motor should not be raised more than 5 inches above the standard position. See When St. Peters Basketball Games Are Today! Be sure to measure carefully and research thoroughly before diving in. Copyright 1999-2023 Boats Group. The Effects of Standard, Lower and Higher Mounting. Wherever the outboard clamping bracket is, use this as the basis for measurement. Check out the full chart of the Mercury outboard model code and its features. 4 0 obj Boat hulls are designed in three basic types that range from slow displacement and semi-displacement hulls to the fastest planing hulls. Cavitation plates are used on the bottom components of boats to help them operate better. A yardstick will help you determine if your outboard engine is at the right height. Engine Oil Type Genuine or Recommended 2str Engine Oil. Then open up the clamp bucket. s = d.createElement("link"); 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. To achieve this, the motor itself has to be attached at the correct height. The form of a boats transom varies depending on the manufacturer and model. loadScript(ptScript); When you measure the width of the stern, mark the center with a grease pencil. Spark Plug 25.0nm(18.4 Ft-lb) (2.55 Kgf-m) s.setAttribute("src", script); It is possible that the motor could hang low while transporting on the boat trailer causing future boat repairs. Repowering your boat is one of the most expensive upgrades you can make. })(); How To Measure Outboard Motor Shaft Length [Long v Short] - Boating Hub stream With the outboard shaft length too long, meaning the prop is too deep in the water, the engine wont be as efficient, and the fuel burn is high. How do you measure a transom on an outboard motor? While this is the case there is certain saltwater motors that are extra extra long at 30 and 35 shaft. The cookie is set by the GDPR Cookie Consent plugin and is used to store whether or not user has consented to the use of cookies. Simply start with the engine in idle, followed by, If you decide to make some custom adjustments we have the. Because of the increased friction, cavitation reduces efficiency. The general guideline for longer shaft outboards is that the transom height should be at least 20 inches (50,8cm) above the waterline. a Detwiler manual jackplate. And thats usually the case since the electric outboards are designed with larger and more efficient propeller that needs longer shaft. Make sure that you are measuring straight up, at a 90 degree angle to Displacement hulled vessels like sailboats and workboats can benefit from a little more space between the hull and cavitation plate, but not much. Eq*^?6R83e+j}UY.(M7k]~4g)g ~wmS{ O7t/o(W|X? 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. You run the risk of possibly unsafe handling if you attempt to put a long shaft engine on a transom designed for a short shaft engine. Measure from the top of the transom to the bottom of the hull. Beginning boaters should be aware of the boats measurements. It also decreases the boats lift and increases the time it takes for the boat to reach plane. With it comes a lot of responsibility and new things to learn including, Why your boat transom needs to be the right height, The pros and cons of properly mounting the outboard motor to the transom, Standard mounting is always best for the beginner, Of course, its always best to go with standard practices when choosing the, Lower mounting is not for the beginning boater, Mounting the motor lower on the boat transom, There is a simple test to see if your outboard motor is set at the best height. Most of the standard engined boats it takes shafts that are 15-30inches long. If it measures between 17 and 22, you'll want to go with a long shaft motor. An inch or two probably wont make a big difference, but any more than that will lead to trouble. Set the end of the tape on the outside edge of the taffrail at the center and measure inward to the inside edge of the taffrail. If it measures between 17 and 22, youll want to go with a long shaft motor. The standard shaft length for most outboard engines less than 125 horsepower is 20 inches. #1: Height function loadScript(script) { Smaller 12-14 foot boats can require either a short or long shaft outboard depending on the style of the boat and the brand. At least if its too long you can raise the motor or "build up" your transom. Of course, its always best to go with standard practices when choosing thebest boat engine. It is extremely important that the boater understands the significance of the transoms height. This, however, is not recommended for the beginning boater. bracket. What is the Virtual Sundance Film Festival? var h = d.getElementsByTagName("head"), Buying a boat can be an exciting purchase. We use cookies on our website to give you the most relevant experience by remembering your preferences and repeat visits. Measuring the shaft length can be done in various ways, but the most common way is by using a tape measure. This alone can outweigh the negatives when deciding to adjust the mount upwards. manufacturer will recommend the outboard height according to the bracket shape and length. As a dealer I don't really like hearing this because there is a chance it could go either way and you have to get it right. Some may call it a standard length while others may call it a short or a long shaft. This transom saver will support the weight of your outboard throughout your road travel, steadily bracing it against the trailer frame to relieve your transom of the weight and impact from consistent bouncing. Take your time and understand your boat and your entire transom. Cavitation is when the propeller is out of the water due to the boat forming a wake of "air bubbles" or "vapor cavities" around the prop. Long Shaft vs. Short Shaft Outboard (What Are the Differences?) Should I take the raft onto the water and measure the exact distance from the top of the transom to the water line? 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. To break it down a bit more for you: Short shafts are 15-inches long. d.addEventListener("DOMContentLoaded", function (e) { measuring; you may have to "extend" the flat part of the Then adjust the motor in a higher hole with a flat head screwdriver. straight edge from the center of the pad, but this time you're measuring Why wont Touch ID be under the screen in the iPhone 15 and iPhone 16?