They keep water out of your prop and increase water pressure in the system. These cookies will be stored in your browser only with your consent. No one wants to have issues with a new transom or boat repairs. This email address is being protected from spambots. Raising the motor increases the speed of the boat while decreasing the effort needed to turn the boat. The boat transom can be flat with zero degree angles. 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. It can also improve the experience of driving a faster boat. In the photo above, we've measured from the motor bracket to the top of the propshaft below or above the pad. s.setAttribute("type", "text/javascript"); 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? It is unsafe to have the engine block too close to the water on a low transom. Advertisement cookies are used to provide visitors with relevant ads and marketing campaigns. The center is the point where your outboard motor is (ideally) located. Check out the Westshore Marine & Leisure google plus page! Upstream Securitys Disruptive Telematics Technology, The challenges of scaling a cloud-based security system, OneStreams unified platform streamlines financial data management, OneStreams impact on the financial software market. Youll need a short shaft outboard if its 15 or less than an inch shorter. Other boats that need long shafts are. How to Measure Transom Height For vessels with transom-mounted outboards, you can easily figure out which type of outboard you need to get. It is possible that the motor could hang low while transporting on the boat trailer causing future boat repairs. It is extremely important that the boater understands the significance of the transoms height. Trimming in, trimming down, and trimming out are all terms that a beginning boater should learn. For over five years he has worked as a newspaper reporter and historic researcher. (We wont go into name-calling here, but the actual term for the cavitation plate is an anti-ventilation plate.) Measuring the shaft length can be done in various ways, but the most common way is by using a tape measure. xmlHttp.setRequestHeader('Content-Type', 'application/json'); Simply start with the engine in idle, followed by trimming the motor out by one-half to full trim. Mounting the outboard a little bit lower than the standard point could avoid the possible ventilation and slip on acceleration. Place the bracket on the transom to the left of the main outboard or rudder. By clicking Accept, you consent to the use of ALL the cookies. These two measurements will give you the length of the shaft you need. With such an important, long-term, and expensive upgrade, its never a bad idea to double-check. var addy_textd53b59933f6c3f2e8b59f1b4a6d41fa5 = 'info' + '@' + 'vanssports' + '.' + 'com';document.getElementById('cloakd53b59933f6c3f2e8b59f1b4a6d41fa5').innerHTML += ''+addy_textd53b59933f6c3f2e8b59f1b4a6d41fa5+'<\/a>'; If you have a short shaft motor, the distance between the top of the transom and the bottom of the boat should be between 15 and 16 inches. 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. If you have a jackplate, you may have to get a bit creative in your height (that I'm aware of); probably the most common is: trimming the motor out by one-half to full trim. The point where these measurements intersect is your centerline. Measure from the top of the transom to the bottom of the hull. When fighting waves from the stern, a 20-inch transom is considerably safer. Pretty easy to figure out but like I said its crucial to pairing a motor with a boat. 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. If the height of the boat transom is off it can cause major issues. So in hopes that this will help out some new boaters this spring, here's a little rundown on outboard shaft sizes and how to figure out which one you actually need. var BCData = {"csrf_token":"d7ecb6b56891bb66aee12dbc01a80162b3ed582c1acbe30f16fc9f1b2abc362f"}; Because of the increased friction, cavitation reduces efficiency. Attention: Remember to measure the outboard shaft length straight up and down instead of measuring along the transom. It is where the outboard is mounted, and some boat owners place the name of the boat. If you are looking to repower, they may be able to offer some sage advice. This, however, is not recommended for the beginning boater. would be more accurate.) All you need to do is measure how much to rise. Before we get started lets see what a boat transom is and what it does. maxTerm: 36, Engine Oil Mixing Ratio Fuel 50: Engine Oil 1. Over time, Boating Hub has grown into a resource for boating enthusiasts around world. These cookies help provide information on metrics the number of visitors, bounce rate, traffic source, etc. See When St. Peters Basketball Games Are Today! With a jack plate, you can mount it exactly where you want it. There are instances where a lower mount may be okay. % Should I take the raft onto the water and measure the exact distance from the top of the transom to the water line? In the second photo, we've measure down from the top of the Detwiler ), and place it on the bottom of the pad in the center. I mean, who wants to purchase something as expensive as an outboard to only realize you bought the wrong one. However, there may be times when a boater strays away from these recommendations. function loadScript(script) { A yardstick will help you determine if your outboard engine is at the right height. former editor at Boating Magazine and contributor to many national publications As a result, the issue is whether my boat need a short shaft or long shaft motor. Safely but briskly accelerate. The transom is the flat vertical section at the rear of the boat. Check out the Westshore Marine & Leisure Youtube page! The boat transom height is measured from the lowest point on the keel along the center line to the spot where the outboard motor's mounting holes bracket rests. What matters is the actual measurement in the specifications, not the name. Boaters who consider going with a higher mount can see increased speeds. So how to determine the outboard shaft length? The boater must also consider if the boat transom support is designed to bear the weight of a higher mount. Now that you have a better understanding of boat transom heights its time to take out the ruler and get the perfect measurements. motor brackets s = d.createElement("script"); If your boat planes, pay extra attention to getting the shaft length as close to perfect as possible. AztH ^zv_ cT,E1K/rAB54| Thats a fairly simple list of symptoms, but if your motor is too low, youll probably notice at least one of them. to where the brackets were actually resting on the transom. manufacturer will recommend the outboard height according to the bracket shape and length. August 9/08). This is handy if youre shopping for second-hand outboards or looking to sell the one that came with your boat. 2019s List of the Best Recreational Pontoon Boats for Sale. The transom is the boats flat vertical part at the back. As summer approaches there will be more boaters taking to the water. Usually speaking, the farther the outboard is set off the transom, the higher the propeller should be in the water (or the higher the outboard can be mounted). Beyond motorboats designed for large outboards, you will see outboards hanging on the sterns of everything from small canoes to large cruising sailboats. But in many cases, its a little more complicated than that alone. With some boats I have a pretty good idea as to what length motor should be hung on them. On most newer center consoles and offshoreboat transoms might include a rear door leading to a swim platform as well as a molded setback bracket. If it measures 15" or with in a inch of that you will need a short shaft outboard. The how to measure the shaft length of an outboard motor is a question that many people have asked. There is a simple test to see if your outboard motor is set at the best height. The first order of business is to measure your boat for the ideal fit. The boater must also consider if the boat transomsupport is designed to bear the weight of a higher mount. What is Transom Height? The outboard shaft length is the vertical distance between the top of the mounting clamp bracket and the bottom of the cavitation plate (aka the ventilation plate). Offshore vessels are often equipped with a large mounting bracket so that the transom can be left at full height. Required fields are marked *. The most common percent angle is probably 12, however spec sheets for O/B and I/O boats may show 10 percent, 12 percent, and 14 degrees. Or it can have an angle degree as high as 30. As a yacht designer and boater, I prefer longer shafts. You may wonder how deep your prop should be in the water. The pros and cons of properly . Then open up the clamp bucket. Smaller inflatables and dinghies needshort shaft motors, whilst bigger boats require long or, in some circumstances, extreme long shaft versions. It is extremely important that the boater understands the significance of the transoms height. The same is true for the newest, high-powered offshore fishing boats, where triple or quadruple motor setups are becoming more and more common. To do so, take a measurement from the very top to the very bottom of the transom in the precise center. If it measures anywhere from 17" to around 22", then your going to want to go with a long shaft motor. However, the motor should not be raised more than 5 inches above the standard position. endobj Yes, if there is adequate space while the engine is tilted in the up position, a larger shaft length than what is specified may be used. This is somewhat similar to #2, in that you are again measuring with a Boat Transom Heights The Beginners Guide, Buying a boat can be an exciting purchase. MPW eBay Store - Thousands of New OEM Old Stock Parts! How high exactly do you have to raise the transom?-. My family and I used it to fish, ski (yes, you can ski behind a pontoon boat), and cruise the lakes near our home. Mounting the outboard motor in accordance with the industry standards is important. Get the latest updates on new products and upcoming sales, 2023 Marine Parts Warehouse Incorporated 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. Actual shaft length is 21.5" on those. addyd53b59933f6c3f2e8b59f1b4a6d41fa5 = addyd53b59933f6c3f2e8b59f1b4a6d41fa5 + 'vanssports' + '.' + 'com'; The distance between the ends of a transom is measured in inches. If you go too short your more than likely going to cavitate and loose power. This measurement would be the inches of steel ruler, etc. If you have a question or need additional information. One of the great things about an outboard motor is how versatile it is. I would also recommend finding your maximum horsepower rating which is located on the yellow coast guard tag towards the back of your boat. For example, you can have the Mercury outboard shaft length by model code. If it measures between 17 and 22, youll want to go with a long shaft motor. See diagram below. (616) 364-0666, On all contiguous US part orders over $100. var h = d.getElementsByTagName("head"), 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. 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. 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. Picking the right shaft length for your outboard is an essential step in getting the best performance from your boat. Your email address will not be published. If it measures anywhere from 17" to around 22", then your going to want to go with a long shaft motor. The shaft length for outboard motors has nothing to do with the water line. Beginning boaters should be aware of the boats measurements. endobj The form of a boats transom varies depending on the manufacturer and model. A: The short answer is Yes. Next, measure from your centerline to where the outboard will be mounted on each side. of the motor off the transom MarinePartsMan.com also says that V6 bass-boat engines have a 20-inch shaft. An inch or two probably wont make a big difference, but any more than that will lead to trouble. Once you know what will fit on your hull, you can fine-tune your choice based on the performance youre looking for and how you use the boat. What types of boat need an extra long shaft? For vessels with transom-mounted outboards, you can easily figure out which type of outboard you need to get. Take your time and understand your boat and your entire transom. Some fishing boats can handle the motor being underwater. In lower mounting, the engine is set lower than the recommended standard. Generally, the anti-ventilation plate on most engines is aligned with the bottom of the vessel. Save my name, email, and website in this browser for the next time I comment. straight edge on the top of the transom to "extend" it out The cookie is used to store the user consent for the cookies in the category "Analytics". The dealer just hit you with the long or short shaft question and you have no clue as to what you need or even what he's talking about. It also decreases the boats lift and increases the time it takes for the boat to reach plane. priceSelector: ".price--withoutTax, span.price.price--withTax", Cavitation plates are used on the bottom components of boats to help them operate better. Knowing how this can affect the overall operation of the boat is a factor to be considered. If it measures between 17 and 22, you'll want to go with a long shaft motor. Industry standards dictate that for short shaft engines the transom height should be 15. While this is the case there is certain saltwater motors that are extra extra long at 30 and 35 shaft. With it comes a lot of responsibility and new things to learn includingboat maintenanceand boat basics. All rights reserved. Follow Westshore Marine & Leisure on Wordpress! Check out some hot FAQs to help you get the proper outboard shaft lengths. 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. The height of the boat transom dictates the size of the outboard motor. Many boat transoms are modified to use a different length of outboard by using a bracket. Ideally, you want the outboards cavitation plate, also called the anti-ventilation plate, to be at the same level as the bottom of your hull. maxMicroAmount: 0.0, Measure from the top of the transom to the bottom of the hull. Step 2: After you get the transom height, add the radius of the propeller (check the user manual, and then technical drawing for the number) to calculate the minimum shaft length needed to make it work. Setting Height of Outboard Motor - YouTube 0:00 / 0:46 Setting Height of Outboard Motor nates90 71 subscribers Subscribe 83 Share 63K views 7 years ago #boatservice #outboardmotor. Each one has a totally different effect on the boats performance. A long shaft engine requires a height of 20 and extra-long shaft engines will need a transom height of 25. Add yours in the comment and Ill get back to you asap. 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. The transom is the flat vertical section at the rear of the boat. 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. You can order an outboard in lengths ranging from 15 inches to 30 inches, depending on its power output and possible uses. 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. gtag('js', new Date()); Any owner seeking the last bit of speed from an outboard-powered boat should grab a yard stick. Allowing the propeller to pull water from underneath and push it out behind the boat. It is extremely important that the boater understands the significance of the transom's height. What the relationship to the pontoons is, I couldn't say. Depending on the manufacturer, size names might change. A transom saver, which can change the spacing between the lower unit and the trailer, negates some of the support. 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). h[0].appendChild(s); 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}'); So you should just measure the height of the boats transom from the center down to the lowest point of the hull, and compare transom height with the outboard shaft length numbers. Finding the right size is a matter of looking at what youve got and taking out the measuring tape. Where Onboard a Boat is the Transom Located and More About Transom Heights A propeller operates based on the height of the transom. Picking the right shaft length is mostly a factor of the transom height or the back of the boat. However, the motor should not be raised more than 5 inches above the standard position. I also love helping others, which is why I created this website. Your at your local outboard dealer shopping for a new motor and the salesman hits you with the question, "short or long shaft?". But, how do you measure it? In addition, motor totes will not harm the finish of the lower unit. You reply, "Im not sure, I think its a long". The general guideline for longer shaft outboards is that the transom height should be at least 20 inches (50,8cm) above the waterline. Since the ventilation plate & foil are burried under water it is obviously too low. The transom is the rear wall of the boat where the outboard engine is mounted in the middle. All boats are different, and the motor manufacturers produce a variety of standard lengths. It doesnt matter if you have a fiberglass boat, bay boat, big or small boat. Whats the best height for my boat motor? This alone can outweigh the negatives when deciding to adjust the mount upwards. To do so, you will want to measure at the exact center of the transom from the very top to the very bottom. Some boats are equipped with transom-hung outboards while others have a bracket. #3. Any questions? 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. A: The answer varies by boat, but here are some rules of thumb for matching a short shaft outboard to your boat. When it gets to the short side (14), When the inner corner of the square comes into touch with the transom, measure the distance between the inside corner of the square and the boat bottom (see drawing below). It varies between different motors and boats. However, the shaft length for smaller boats could be long or short depending on its style, speed requirement, etc. document.getElementById('cloakd53b59933f6c3f2e8b59f1b4a6d41fa5').innerHTML = ''; High powered boats usually only come in long and extra-long variants. The lowest point will likely be directly under your drain plug if youve got one. Simply start with the engine in idle, followed by, If you decide to make some custom adjustments we have the. You will also risk hitting bottom or submerge objects more frequently such as rocks or logs. You need JavaScript enabled to view it. Place the point of a yardstick at the middle of the top of the boat transom. The first step is to determine the height of your boat's transom. Outboards designed for saltwater applications usually have longer shafts. enableMoreInfoLink: true, This could also affect your travelling capabilities on the boat trailer. Boat transom angles play a pivotal role in the flexibility of the boats trimming abilities. Step 2 requires the propeller's radius (check the user manual and then the technical drawing). Problems with getting the ventilation plate too low include slower hole-shot and lower top-end speeds. A1: Broadly speaking, the outboard motor shaft length for pontoon boat, bass boat, or other larger boats should be long shaft. Copyright 1999-2023 Boats Group. 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. This would not be a good thing. want to measure from the transom to the flat part of this bracket, Repowering your boat is one of the most expensive upgrades you can make. Sluggish speeds, poor handling, heavy spray, porpoising, or even water pushing up into the cowling are all signs that an outboard is set too low. However, there may be times when a boater strays away from these recommendations. publicId: "32bf3437d1346295e03ebcf545f9c839", How to Buy a Boat: Tips for a First Time Buyer, Top 10 New Fishing Boats for Under $20,000, What Type is Right for You? Industry transom height standards have been evolved during the last 30 years: 15 for short shaft engines, 20 for long shaft engines, and 25 for extra-long shaft engines. 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. In the case of a larger offshore boat, it may be to the top of a cutout on the . 3 0 obj Keep these numbers in mind if you ever have a need for a new outboard motor for your boat. Of course, its always best to go with standard practices when choosing thebest boat engine. The clamp bracket on the latest Mercury Four-Stoke-model outboards has five mounting bolt holes spaced .75 inches apart.
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