You can order an outboard in lengths ranging from 15 inches to 30 inches, depending on its power output and possible uses. Some fishing boats can handle the motor being underwater. To sum up, there is a simple calculator of the shaft length for outboard motors: Outboard Shaft Length = Transom Height +/- Factors. 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. Any questions? With this in mind, how can I determine if my outboard has a short or long shaft? To do so, take a measurement from the very top to the very bottom of the transom in the precise center. One of the main concerns is causing the engine to overheat if not enough water reaches the engine to keep it cool. If it measures anywhere from 17" to around 22", then your going to want to go with a long shaft motor. Some boats are equipped with transom-hung outboards while others have a bracket. Generally, the anti-ventilation plate on most engines is aligned with the bottom of the vessel. In the second photo, we've measure down from the top of the Detwiler Also, the boat will be more likely to hit bottom or submerge objects such as rocks or logs. #1: Height Move the bracket as close to the center of the transom as possible while still maintaining clearance to allow the main outboard or rudder to reach its full range of motion without contacting the kicker motor. gtag('config', 'G-QX0Y76NH40'); Whether your on a pontoon boat, fishing boat, or speedboat boating is always one of the best times you can have. At least if its too long you can raise the motor or "build up" your transom. Always weigh the risks of making adjustments. Before we start measuring the outboard shaft length, lets get it clear about whats referring to when we talk about the outboard shaft length. These are vertically aligned so the boater can make adjustments. 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. The outboard comes with mounting holes and brackets. No one wants to have issues with a new transom or boat repairs. This cookie is set by GDPR Cookie Consent plugin. This alone can outweigh the negatives when deciding to adjust the mount upwards. A: Any boat that has a 21 to 27 inch aft transom will need an extra long shaft outboard. If possible for your peace of mind and not let down that magnificent purchase opportunity, place that 08 kicker at back transom and test for yourself. If we run into that scenario, I would still show you the different options of motors and go over pricing, but I would also ask you to hold off and do one thing before you pull the trigger. 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. In the case of a larger offshore boat, it may be to the top of a cutout on the . The cookie is used to store the user consent for the cookies in the category "Other. A2: Instead of changing to the short outboard shaft, you can try the Jack Plate first. It also cuts into speed and fuel efficiency. So if you are measuring the outboard shaft length for the powerboat, planing boat, or any boat for which the speed is the priority, take the outboard shaft length 1 to 1.5 (depending on your boat types) shorter than standard would be better. Attention: Remember to measure the outboard shaft length straight up and down instead of measuring along the transom. Picking the right shaft length for your outboard is an essential step in getting the best performance from your boat. Or it can have an angle degree as high as 30. If you have a jackplate, you may have to get a bit creative in your The correct shaft length for your boat depends on a few factors. 2019s List of the Best Recreational Pontoon Boats for Sale. Offshore vessels are often equipped with a large mounting bracket so that the transom can be left at full height. The collapsing bubbles are loaded with extremely low-pressure water vapor, which causes damage to a variety of surfaces as they collapse. It was a 23-foot Crestliner Grand Cayman pontoon boat. The transom is the boats flat vertical part at the back. This number will likely be shorter than that for a single-engine installation since you do not necessarily measure to the point of the keel. document.getElementById('cloakd53b59933f6c3f2e8b59f1b4a6d41fa5').innerHTML = ''; He is also a certified marine technician and the author of a popular text on writing local history. I hope this helps someone out in their search for a new or newer outboard this season. If you are looking to repower, they may be able to offer some sage advice. I mean it is better to be safe than sorry, am I right? How high exactly do you have to raise the transom?-. The cookie is used to store the user consent for the cookies in the category "Analytics". One of the great things about an outboard motor is how versatile it is. displayPrimeOffers: true, Or measure from the main engine prop up to the water line? Here is a picture that shows you exactly where the outboard motor shaft length stands: Usually the shaft length for outboard motors falls into the following 4 sizes: In practice, you may find the outboard motor shaft length varies among different brands and manufacturers like the Honda,Suzuki, Yamaha, Torqeedo, etc. As mentioned above, the operation of the propeller relies on the transom height. Why Rebounding Is A Key Skill for Fouth Players To Learn, Tips For Attacking a Zone Defense as a Youth Basketball Team, Why This is a Big Deal for the Sports Betting Industry. 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. Mounting the motor lower on the boat transomcan createexcessive spray, increase case drag, reduce underwater clearance, and negatively impact faster boats. } Boats with more engine power and weight require longer shaft outboards for better balance. So how to measure outboard shaft length? The shaft length for outboard motors has nothing to do with the water line. Make sure that you are measuring straight up, at a 90 degree angle to xmlHttp.open('POST', 'https://bes.gcp.data.bigcommerce.com/nobot'); 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. When fighting waves from the stern, a 20-inch transom is considerably safer. Bass boats, ski boats, or center cockpit vessels will want to double-check their measurements to get it just right. You will also risk hitting bottom or submerge objects more frequently such as rocks or logs. You may wonder how deep your prop should be in the water. The distance between the ends of a transom is measured in inches. Other boats that need short shafts are: A: If you have a small boat with a 18 to 21 inch aft transom, youll most likely need a long shaft outboard. The point where these measurements intersect is your centerline. A long shaft engine requires a height of 20 and extra-long shaft engines will need a transom height of 25. When mounting the engine, you want the cavitation plate to be 1 above the boat bottom for every 12 away from the transom. boats.com, 1221 Brickell Avenue, 23rd Floor, Miami, FL 33131, USA. *The Factors indicates the adjustment affected by on your boat type, the outboard working environment, and the transom distance as discussed above. Cutting the transom down is the only legal method to utilize a short shaft engine on a tall transom. 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. Here we look at the effects of standard, lower and higher mounting. (3) Move horizontally across the chart until you hit the graph curve. 12 Small Fishing Boat Accessories to Buy Today. 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. On this type of boat, if you are in doubt, default to the longer-shafted outboard. But in many cases, its a little more complicated than that alone. will be to the flat part; if you measure to the bottom of the brackets You need JavaScript enabled to view it. While this is the case there is certain saltwater motors that are extra extra long at 30 and 35 shaft. MPW eBay Store - Thousands of New OEM Old Stock Parts! The performance of these boats depends on quite a lot of factors, but getting the outboard length just right is an essential first step. Wherever the outboard clamping bracket is, use this as the basis for measurement. Step 2 requires the propeller's radius (check the user manual and then the technical drawing). Knowing how this can affect the overall operation of the boat is a factor to be considered. The pros and cons of properly . We also use third-party cookies that help us analyze and understand how you use this website. This is the dimension you'll need to know when deciding between a short shaft, long shaft or extra long shaft for your outboard motor. h[0].appendChild(s); Here we will guide you in how to get the right boat transom height. Tightening Torque for Engine. Your email address will not be published. :$I>M W$h"%U_yzIb?]NHg_G|r@nX eTf."SQ Rebuilt - What You Need to Know, Lower Unit and Sterndrive Break-In Instructions. })(); var interval = setInterval(function () { In the case of a dinghy or johnboat, this point may be the top of the transom. 4 0 obj Generally, short shaft outboards are 15 inches, long shaft outboards are 20 inches, and extra-long outboards are 25 inches. This distance is very important to the performance of you boat. If you are running a twin-engine setup, then measure the same distance from each clamping plate to the bottom of the hull. Over time, Boating Hub has grown into a resource for boating enthusiasts around world. As summer approaches there will be more boaters taking to the water. Determining Your Boat Transom Angle The transom angle - commonly measured in degrees - is the transom's vertical inclination. By clicking Accept, you consent to the use of ALL the cookies. All boats are different, and the motor manufacturers produce a variety of standard lengths. The standard shaft length for most outboard engines less than 125 horsepower is 20 inches. I run a 9.9 Mercury Bigfoot 20" shaft off the swim platform of my 89 Trophy 2160. Then finally test your outboard, if the mount is perfect. Simply start with the engine in idle, followed bytrimming the motor out by one-half to full trim. In lower mounting, the engine is set lower than the recommended standard. No matter what size of boat you are running, one of the most critical choices you can make when buying an outboard motor is the shaft length. var path = 'hr' + 'ef' + '='; 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. Many boat transoms are modified to use a different length of outboard by using a bracket. want to measure from the transom to the flat part of this bracket, Having the cavitation plate too low will cause excess drag and reduced performance at high speeds. Raising the motor increases the speed of the boat while decreasing the effort needed to turn the boat. I would also recommend finding your maximum horsepower rating which is located on the yellow coast guard tag towards the back of your boat. Depending on the manufacturer, size names might change. These are vertically aligned so the boater can make adjustments. Raising an outboard higher on the transom can reduce drag and raise top speed. Actual shaft length is 21.5" on those. Transom Outboard Engine Position - YouTube 0:00 / 0:56 Transom Outboard Engine Position BOATING SCENE 763 subscribers 609 211K views 5 years ago www.boatingscene.com.au Sometimes when your. You must be still in the blue about that matter. However, the shaft length for smaller boats could be long or short depending on its style, speed requirement, etc. |. 3 0 obj August 9/08). If your outboard motor height. 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. 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. Its where the outboard motor is attached, and its also where some boat owners put the boats name. On the downside, a higher mount can interfere with the boaters steering capabilities. 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. It can also improve the experience of driving a faster boat. Most of the time, adding a hydrofoil to an outboard improves performance. What is Transom Height? For most boaters this is a no brainer, but for the novice or inexperienced boater it may be a tougher question. Safely but briskly accelerate. 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. The motor is what powers the boat so the two go hand-in-hand. Whats the best height for my boat motor? There is a simple test to see if your outboard motor is set at the best height. What are Apple Podcasts Subscriptions and Channels? The greater the number, the more the drive may sway (also called tuck under or negative trim). The prop will be in cleaner, harder water as it advances farther aft, making it more efficient. Also, how do you determine the length of an outboard transom? Outboards designed for saltwater applications usually have longer shafts. Another important measurement is the transom angle. Keith Allen, a 1979 graduate of Valley City State College, has worked at a variety of jobs including computer operator, medical clinic manager, radio talk show host and potato sorter. Amazon has plate extensions to allow adjustments without buying a new motor: T-H Marine Jack Plate Extension. Which Navigation Lights Does Your Boat Need? To do so, you will want to measure at the exact center of the transom from the very top to the very bottom. PayTomorrow.mpeInit({ Increased RPM and additional horsepower feed the need for speed. How the outboard will sit on the back of the boat depends on how the transom is designed. If the height of the boat transom is off it can cause major issues. There is a simple test to see if your outboard motor is set at the best height. Triton. Its still smart to measure it yourself though, just in case, the design changed over the years. clearInterval(interval); Will Charpentier is a writer who specializes in boating and maritime subjects. Thats it. Some fishing boats can handle the motor being underwater. The cookie is used to store the user consent for the cookies in the category "Performance". <> With it comes a lot of responsibility and new things to learn includingboat maintenanceand boat basics. Gear Oil Quantity 195ml(6.6 Fl.oz.) Ill also explain the difference between short and long shafts and how they vary by type of boat. The Effects of Standard, Lower and Higher Mounting. The transom is the flat vertical section at the rear of the boat. Boat transom angles play a pivotal role in the flexibility of the boats trimming abilities. Why wont Touch ID be under the screen in the iPhone 15 and iPhone 16? To do so, take a measurement from the very top to the very bottom of the transom in the precise center. % The engine may be lifted one inch for every eight to ten inches of distance between the transom and the prop, according to a boat riggers rule of thumb. addyd53b59933f6c3f2e8b59f1b4a6d41fa5 = addyd53b59933f6c3f2e8b59f1b4a6d41fa5 + 'vanssports' + '.' + 'com'; All rights reserved. Take your time and understand your boat and your entire transom. Finding the right size is a matter of looking at what youve got and taking out the measuring tape. Small portable outboards ranging from 2 to 20 horsepower are usually sold only in short or long shaft versions. Happy boating! var addy_textd53b59933f6c3f2e8b59f1b4a6d41fa5 = 'info' + '@' + 'vanssports' + '.' + 'com';document.getElementById('cloakd53b59933f6c3f2e8b59f1b4a6d41fa5').innerHTML += ''+addy_textd53b59933f6c3f2e8b59f1b4a6d41fa5+'<\/a>'; Take your time and understand your boat and your entire transom. To do so, you will want to measure at the exact center of the transom from the very top to the very bottom. For vee-shaped hulls, the lowest spot of the hull will come to point, while on flat-bottomed boats it will be more or less level. MarinePartsMan.com also says that V6 bass-boat engines have a 20-inch shaft. All things considered, sticking with the industry standard is best for the beginner. var h = d.getElementsByTagName("head"), If the propeller fails to ventilate, the motor is mounted to low. The transom is the back of the boat where the motor is hung. It also decreases the boats lift and increases the time it takes for the boat to reach plane. if (PayTomorrow) { This was the height of my 225 Yamaha on my TR21 var BCData = {"csrf_token":"d7ecb6b56891bb66aee12dbc01a80162b3ed582c1acbe30f16fc9f1b2abc362f"}; If you have a fast boat, getting the outboards cavitation plate at the same level of the hull will ensure quick hole shot and fast top-end speeds. Then, you can pick the right engine. The general guideline for longer shaft outboards is that the transom height should be at least 20 inches (50,8cm) above the waterline. Whether your on a pontoon boat, fishing boat, or speedboat boating is always one of the best times you can have. s.setAttribute("src", script); Brackets are also handy for boats that do not have flat transoms, like canoe-stern sailboats or fan-tailed motor vessels. Most of the standard engined boats it takes shafts that are 15-30inches long. Step 4. Performance cookies are used to understand and analyze the key performance indexes of the website which helps in delivering a better user experience for the visitors. The faster your boat, the more critical it is to get the sizing just right. Another important measurement is the transom angle. When trimming your motor, they provide you a greater bow response. Read the measurement on the transoms bottom. The cookie is set by GDPR cookie consent to record the user consent for the cookies in the category "Functional". There xmlHttp.send('{"store_id":"369079","timezone_offset":"-5","timestamp":"2023-03-04T05:39:31.71020200Z","visit_id":"e2642be3-34e5-4a48-b89d-639d139834e0","channel_id":1}'); What the relationship to the pontoons is, I couldn't say. The first order of business is to measure your boat for the ideal fit. Smaller 12-14 foot boats can require either a short or long shaft outboard depending on the style of the boat and the brand. Now that you have a better understanding of boat transom heights its time to take out the ruler and get the perfect measurements. Lubrication System Engine Oil Mixed Gasoline. If youre going the other way around and trying to figure out how long the shaft on your outboard is, measuring it is equally easy. your motor will be higher.) It will ensure that the outboards trim will be effective, and it will save you gas too. Learn More About Your Boats Systems By Joining The Born Again Boating Academy! While this is the case there is certain saltwater motors that are extra extra long at 30 and 35 shaft. But, how do you measure it? There are also specialty motor shaft lengths. Knowing how this can affect the overall operation of the boat is a factor to be considered. Or it can have an angle degree as high as 30. If youd like to see this in video format, skip to 0:44 in the below YouTube Video: Is it OK to put a long shaft outboard on a boat thats rated for a short shaft? To make the yard stick long enough to measure the length of all the clubs, tape the ruler to the top. This provides seaworthiness and offers maximum protection from large seas. Simply start with the engine in idle, followed by, If you decide to make some custom adjustments we have the. But opting out of some of these cookies may affect your browsing experience. As with anything, there are exceptions to the rule. The brackets can add 1 inch to the overall mounting height of the outboard. This also means it can affect the safety of the boat. 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. The boater must also consider if the boat transomsupport is designed to bear the weight of a higher mount. publicId: "32bf3437d1346295e03ebcf545f9c839", Save my name, email, and website in this browser for the next time I comment. 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. 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. All rights reserved. Before we get started lets see what a boat transom is and what it does. Use the mounting bracket on the motor to know where it will sit on the boat. If it measures between 17 and 22, you'll want to go with a long shaft motor. I show you how to consistently measure your prop to pad height. Necessary cookies are absolutely essential for the website to function properly. (127 mm). Look at the part of your motor that would be The mounting height of the outboard engine is the equivalent of the distance between the base of the motor and the top of the propeller. Charles Plueddeman is Boats.com's outboard, trailer, and PWC expert. Engine Oil Mixing Ratio Fuel 50: Engine Oil 1. }, 100); These allow the mounting of a standard length outboard behind the transom. Gear case sits just below or at the hull depth due to the deep v. This, however, is not recommended for the beginning boater. There are instances where a lower mount may be okay. disregard the "hooks" at the front of the Recommended Engine Oil 2-Stroke Outboard Motor Oil. If so, send me an You need JavaScript enabled to view it. This is also known as the shaft length. 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. On the downside, a higher mount can interfere with the boaters steering capabilities. If it measures anywhere from 17" to around 22", then your going to want to go with a long shaft motor. primeApr: 12.99, A yardstick will help you determine if your outboard engine is at the right height. In addition, motor totes will not harm the finish of the lower unit. maxMicroAmount: 0.0, An inch or two probably wont make a big difference, but any more than that will lead to trouble. The transom is the rear wall of the boat where the outboard engine is mounted in the middle. In step 3, add another 10 cm (4") to the previous calculation in order to develop the ideal shaft length. With such an important, long-term, and expensive upgrade, its never a bad idea to double-check. However, there may be times when a boater strays away from these recommendations. For over five years he has worked as a newspaper reporter and historic researcher. The form of a boats transom varies depending on the manufacturer and model. #3. Some outboards have a serial number that tells you which shaft length to go for. A: The short answer is Yes. Other boats that need extra long shafts are: Read my other articles on outboard motors. The lowest point will likely be directly under your drain plug if youve got one. The amount of degrees the transom leans back from vertical is known as the transom angle. Youll also want to pay attention when youre in shallow water because your prop will be lower than normal. displayMicroOffers: false, This measurement would be the inches of 1 0 obj Two years ago, I bought a Boston Whaler to fish off the coast. See When St. Peters Basketball Games Are Today! var ptScript = "https://cdn.paytomorrow.com/js/pt-mpe.min.js"; Having the cavitation plate a bit lower than the transom is preferable to having it too high. Doing this can have adverse effects. These cookies will be stored in your browser only with your consent. d.addEventListener("DOMContentLoaded", function (e) { Smaller boats may use adjustable jack plates that can be changed to fit any outboard. #2. var addyd53b59933f6c3f2e8b59f1b4a6d41fa5 = 'info' + '@'; would be more accurate.) For boats equipped with a bracket, calculate the same measurement but based on the bracket and not the transom. Long shafts are 20-inches long. to where the brackets were actually resting on the transom. s.setAttribute("rel", "stylesheet"); Keep these numbers in mind if you ever have a need for a new outboard motor for your boat. the aluminum plate on top of the transom), to the bottom of the motor Picking the right shaft length is mostly a factor of the transom height or the back of the boat. Using your existing control box and gauges will save you quite a bit of money in the end. When the boat transom is too low, the motor could end up underwater. Small motors built for sailboats might come in a unique configuration with an extremely long shaft since these are mounted higher off the water. When you measure the width of the stern, mark the center with a grease pencil.
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