how to measure transom height for outboard motor

What is the Virtual Sundance Film Festival? } Or it can have an angle degree as high as 30. var prefix = 'ma' + 'il' + 'to'; Boat hulls are designed in three basic types that range from slow displacement and semi-displacement hulls to the fastest planing hulls. Buying a boat can be an exciting purchase. would be more accurate.) <>/ExtGState<>/XObject<>/ProcSet[/PDF/Text/ImageB/ImageC/ImageI] >>/MediaBox[ 0 0 595.2 841.8] /Contents 4 0 R/Group<>/Tabs/S/StructParents 0>> Re: Dinghy with a long shaft motor? e-mail Read the following to get the optimal shaft length for outboard motors! 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. Boat Transom Heights The Beginners Guide, Buying a boat can be an exciting purchase. Take the center measurement from the top to the bottom of the hull. It doesnt matter if you have a fiberglass boat, bay boat, big or small boat. Basically, there are three main ways to measure motor Gear Oil Quantity 195ml(6.6 Fl.oz.) Check out some hot FAQs to help you get the proper outboard shaft lengths. The transom is the flat vertical section at the rear of the boat. What the relationship to the pontoons is, I couldn't say. (Putting a The mounting height of an outboard motor can impact the speed and handling characteristics of the boat. var interval = setInterval(function () { Wherever the outboard clamping bracket is, use this as the basis for measurement. The motor length corresponds to the transom height of the boat, measured from the keel to gunwale at the transom. The shaft length for outboard motors has nothing to do with the water line. You can order an outboard in lengths ranging from 15 inches to 30 inches, depending on its power output and possible uses. bassboat can be a bit confusing at times; hopefully this will help sort A2: Instead of changing to the short outboard shaft, you can try the Jack Plate first. window.dataLayer = window.dataLayer || []; The prop will be in cleaner, harder water as it advances farther aft, making it more efficient. The greater the number, the more the drive may sway (also called tuck under or negative trim). parallel with the straight edge. In the past, though, it housed the officers and captain of 17th, 18th and 19th century sailing ships. Higher mounting decisions should be left to the professionals. A big NO. the aluminum plate on top of the transom), to the bottom of the motor A retired ship captain, Charpentier holds a doctorate in applied ocean science and engineering. 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. This alone can outweigh the negatives when deciding to adjust the mount upwards. from the transom. When trimming your motor, they provide you a greater bow response. Measure straight down to the lowest point on the hull. Here we look at the effects of standard, lower and higher mounting. var h = d.getElementsByTagName("head"), Thats it. The motor is what powers the boat so the two go hand-in-hand. help with shaft length for a kicker - iboats Boating Forums Industry standards dictate that for short shaft engines the transom height should be 15. Guide to Boat Transom Heights - Marine Parts Warehouse Typical motor lengths include the following. (3) Move horizontally across the chart until you hit the graph curve. Selecting the Correct Size Outboard Shaft, What is the Best Outboard Motor for Saltwater, Diagnosing Common Outboard Motor Problems, Best Beginner Boats Everything You Need to Know. 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. Depending on the manufacturer, size names might change. Place the clubs bottom on the ground as though it were going to be used to strike a golf ball. priceSelector: ".price--withoutTax, span.price.price--withTax", mpeInit(); Here we will guide you in how to get the right boat transom height. It is extremely important that the boater understands the significance of the transoms height. By clicking Accept, you consent to the use of ALL the cookies. The distance between the ends of a transom is measured in inches. As with anything, there are exceptions to the rule. Outboard Motor Shaft Length - LeeRoy's Ramblings The pros and cons of properly . Transom Outboard Engine Position - YouTube With some boats I have a pretty good idea as to what length motor should be hung on them. For really big boats, the biggest and baddest six- or eight-cylinder outboards can have extra-extra long shafts up to 30 inches. :$I>M W$h"%U_yzIb?]NHg_G|r@nX eTf."SQ The propellers will also have trouble reaching the water. These cookies track visitors across websites and collect information to provide customized ads. The Effects of Standard, Lower and Higher Mounting. displayMicroOffers: false, 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. Remember, if you use a longer outboard shaft than you need you will be increasing your draft. Not to measure boat speed, but to gauge the mounting height of the outboard motor on the boat transom. Check out the Westshore Marine & Leisure Youtube page! Well, raising the outboard motor can be an easy task for you. mpeSelector: ".pt-mpe", Also, how do you determine the length of an outboard transom? Your email address will not be published. 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. Of course, its always best to go with standard practices when choosing thebest boat engine. Outboard motors can be fitted to a variety of boats, so manufacturers have standardized their engines to go on virtually anything. Or it can have an angle degree as high as 30. You may wonder how deep your prop should be in the water. How To Measure Outboard Motor Shaft Length [Long v Short] - Boating Hub You need JavaScript enabled to view it. See diagram below. Many boat transoms are modified to use a different length of outboard by using a bracket. Installing a Kicker Motor Bracket - Gone Outdoors Doing this can have adverse effects. Beginning boaters should be aware of the boats measurements. Add yours in the comment and Ill get back to you asap. I would ask you to go back and measure the transom of your boat. This, however, is not recommended for the beginning boater. There are instances where a lower mount may be okay. steel ruler, etc. Raising an outboard higher on the transom can reduce drag and raise top speed. Anything bigger than that your obviously going to need an extra long shaft. I live for the weekends when I can go out on the water and escape the stress of life on land. 7. How high exactly do you have to raise the transom?- - Outboard Jets Before we get started lets see what a boat transom is and what it does. 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. The transom angle is the vertical incline of the transom and is measured in degrees. With such an important, long-term, and expensive upgrade, its never a bad idea to double-check. The transom angle is the vertical incline of the transom and is measured in degrees. You also have the option to opt-out of these cookies. Other boats that need long shafts are. August 9/08). 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. 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. As a dealer I run into this situation from time to time, which is fine but getting the right length outboard for your boat is crucial. The same is true for the newest, high-powered offshore fishing boats, where triple or quadruple motor setups are becoming more and more common. The transom is the flat vertical section at the rear of the boat. var ptScript = "https://cdn.paytomorrow.com/js/pt-mpe.min.js"; Measuring Motor Height - BassBoat Central The cookie is used to store the user consent for the cookies in the category "Performance". What matters is the actual measurement in the specifications, not the name. 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. Tightening Torque for Engine. Outboard shaft length plays a crucial role in the performance of your 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. enableMoreInfoLink: true, 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. However, youll notice a little increase in drag and a decrease in top-end performance. Some boats are equipped with transom-hung outboards while others have a bracket. PayTomorrow.mpeInit({ Two years ago, I bought a Boston Whaler to fish off the coast. A transom saver, which can change the spacing between the lower unit and the trailer, negates some of the support. Smaller inflatables and dinghies needshort shaft motors, whilst bigger boats require long or, in some circumstances, extreme long shaft versions. Get the latest updates on new products and upcoming sales, 2023 Marine Parts Warehouse Incorporated The standard shaft length for most outboard engines less than 125 horsepower is 20 inches. So how to measure outboard shaft length? % A: The answer varies by boat, but here are some rules of thumb for matching a short shaft outboard to your boat. This is somewhat similar to #2, in that you are again measuring with a trimming the motor out by one-half to full trim. |. Follow Westshore Marine & Leisure on Twitter! All rights reserved. #3. 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. function loadScript(script) { Offshore vessels are often equipped with a large mounting bracket so that the transom can be left at full height. Another important measurement is the transom angle. If your outboard motor height. 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. Raising the motor increases the speed of the boat while decreasing the effort needed to turn the boat. h[0].appendChild(s); Take a long straight edge, (long carpenter's level or long Boat Transom Heights - The Beginner's Guide | My Westshore When mounting the engine, you want the cavitation plate to be 1 above the boat bottom for every 12 away from the transom. Simply start with the engine in idle, followed by, If you decide to make some custom adjustments we have the. Commonly, the transom angle ranges from 0-30 degrees, with the average transom angle set at 14 degrees. Measure the area of the transom directly where the engine will be mounted. Because of the increased friction, cavitation reduces efficiency. Motor height on pontoon? | Boating Forum - iboats Boating Forums Extra-long shafts are 25-inches long. Boaters who consider going with a higher mount can see increased speeds. A reversetransom that sits too high can impact the propellers of the motor and motor bracket. This distance is very important to the performance of you boat. The height of the boat transom dictates the size of the outboard motor. At least if its too long you can raise the motor or "build up" your transom. However, you will need an understanding of how the degrees will alter the boats usability. I show you how to consistently measure your prop to pad height. As a yacht designer and boater, I prefer longer shafts. Actually there is no designated letter for short shaft. Its still smart to measure it yourself though, just in case, the design changed over the years. Always weigh the risks of making adjustments. His works have appeared in regional newspapers in North Dakota and in "North Dakota Horizons" and "Cowboys and Indians" magazines. 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. This cookie is set by GDPR Cookie Consent plugin. It is unsafe to have the engine block too close to the water on a low transom. The average transom angle is around 14 degrees. It is very versatile as it generally . The flat part of the bracket that rests on the transom when mounted will give you the same point of reference as the transom does on the boat. How do you measure a transom on an outboard motor? In addition, motor totes will not harm the finish of the lower unit. Since the ventilation plate & foil are burried under water it is obviously too low. 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. Most transom savers can support up to a 150HP motor, which is sufficient for most regular boats. But in many cases, its a little more complicated than that alone. Boost Speed with Outboard Engine Height Adjustments This exhaust port should be about 1 inch above the water line when the boat is idling. If you said you have a pontoon or a larger style boat such as a bass boat or speed boat, I would be pretty confident in saying it needs a long shaft. Check the literature about your model boat online, and you may be surprised to find that the number is published for you. Most of the standard engined boats it takes shafts that are 15-30inches long. maxAmount: 6500.0, In lower mounting, the engine is set lower than the recommended standard. My family and I used it to fish, ski (yes, you can ski behind a pontoon boat), and cruise the lakes near our home. You can find your Mercury outboard model code on an ID plate or sticker. endobj This would not be a good thing. and I'll explain it better, (or point you to someone that can help. 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. It is where the outboard is mounted, and some boat owners place the name of the boat. In lower mounting, the engine is set lower than the recommended standard. It doesnt matter if you have a fiberglass boat, bay boat, big or small boat. WHAT LENGTH OUTBOARD DO YOU REALLY NEED? - Van's Sport Center And thats usually the case since the electric outboards are designed with larger and more efficient propeller that needs longer shaft. Boat transomangles play a pivotal role in the flexibility of the boats trimming abilities. Youll need a short shaft outboard if its 15 or less than an inch shorter. Some fishing boats can handle the motor being underwater. out the confusion. Then, you can pick the right engine. A yardstick will help you determine if your outboard engine is at the right height. Also, the boat will be more likely to hit bottom or submerge objects such as rocks or logs. #2. However, the shaft length for smaller boats could be long or short depending on its style, speed requirement, etc. I run a 9.9 Mercury Bigfoot 20" shaft off the swim platform of my 89 Trophy 2160. Long Shaft vs. Short Shaft Outboard (What Are the Differences?) So from there, I will try to help out by asking questions about your boat such as what type it is and the length. Make sure that you are measuring straight up, at a 90 degree angle to ), and place it on the bottom of the pad in the center. 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). One of the main concerns is causing the engine to overheat if not enough water reaches the engine to keep it cool. Next, measure from your centerline to where the outboard will be mounted on each side. You dont have to be a mathematician to determine the correct boat transomangle. To achieve this, the motor itself has to be attached at the correct height. s.setAttribute("src", script); (In the case of the faster Small motors built for sailboats might come in a unique configuration with an extremely long shaft since these are mounted higher off the water. function gtag(){dataLayer.push(arguments);} The average transom angle is around 14 degrees. As mentioned above, the operation of the propeller relies on the transom height. In the case of a dinghy or johnboat, this point may be the top of the transom. The rearmost structural member of your boat, it not only distributes the stress of the hull generated by the bow's impact as it cleaves the water, it's the place you hang your outboard motor. Follow Westshore Marine & Leisure on Wordpress! if (PayTomorrow) { Beefier jack plates can be fitted should a boater be looking to mount an outboard with a shorter shaft than their transom demands. Step 4. 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. Mounting kicker motor - General Discussion Forum | In-Depth Outdoors Simply start with the engine in idle, followed bytrimming the motor out by one-half to full trim. Whether you already own a boat or looking for your first watercraft we are here to service your needs. 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. Attention: Remember to measure the outboard shaft length straight up and down instead of measuring along the transom. want to measure from the transom to the flat part of this bracket, A deep Vee hull will result in a different measurement than a flatter . To do so, take a measurement from the very top to the very bottom of the transom in the precise center. It is extremely important that the boater understands the significance of the transoms height. If you are running a slower boat, the exact location of the ventilation plate is less important. Place the rulers end on the ground behind the club and let the club to rest on top of it. If it measures anywhere from 17" to around 22", then your going to want to go with a long shaft motor. The center is the point where your outboard motor is (ideally) located. He is also a certified marine technician and the author of a popular text on writing local history. Boats that use longer outboard shafts include: 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. motor brackets Mounting the outboard a little bit lower than the standard point could avoid the possible ventilation and slip on acceleration. One of the great things about an outboard motor is how versatile it is. To sum up, there is a simple calculator of the shaft length for outboard motors: Outboard Shaft Length = Transom Height +/- Factors. When the boat transom is too low, the motor could end up underwater. Most of the time, adding a hydrofoil to an outboard improves performance. Step 2: Three Variables to Consider The general guideline for longer shaft outboards is that the transom height should be at least 20 inches (50,8cm) above the waterline. As mentioned above, the operation of the propeller relies on the transom height. 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. If the height of the boat transom is off it can cause major issues. How-To: Pick A Great Portable Outboard Motor (2023 Guide) The propellers will also have trouble reaching the water. How high exactly do you have to raise the transom?-. It is possible that the motor could hang low while transporting on the boat trailer causing future boat repairs. measuring; you may have to "extend" the flat part of the 5/rC,aQhsK@Q. 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. This cookie is set by GDPR Cookie Consent plugin. Adjusting the mounting height of an outboard on the boat transom can affect performance and every boat can be different, so actual on-water testing is best. Mounting the motor lower on the boat transomcan createexcessive spray, increase case drag, reduce underwater clearance, and negatively impact faster boats. Required fields are marked *. Copyright 1999-2023 Boats Group. The engine must be linked to the transom at the proper height for a propeller to best meet specific boating demands. For example, you can have the Mercury outboard shaft length by model code. What Is a Transom? Where Onboard a Boat is It Located? Picking the right shaft length for your outboard is an essential step in getting the best performance from your boat. xmlHttp.open('POST', 'https://bes.gcp.data.bigcommerce.com/nobot'); Its where the outboard motor is attached, and its also where some boat owners put the boats name. Some outboards have a serial number that tells you which shaft length to go for. You will also risk hitting bottom or submerge objects more frequently such as rocks or logs. This also means it can affect the safety of the boat. Be sure to measure carefully and research thoroughly before diving in. The boater must also consider if the boat transomsupport is designed to bear the weight of a higher mount. Use the mounting bracket on the motor to know where it will sit on the boat. If it measures between 17 and 22, youll want to go with a long shaft motor. s.setAttribute("type", "text/javascript"); will be to the flat part; if you measure to the bottom of the brackets since 1986. primeApr: 12.99, Oftentimes you will want to adjust the outboard shaft length in order to improve the boat performance such as speed. On this type of boat, if you are in doubt, default to the longer-shafted outboard. Like Westshore Marine & Leisure on Facebook! PDF Outboard shaft lengths and transoms - Boat Builder Central (function (d) { Measuring the shaft length can be done in various ways, but the most common way is by using a tape measure. Place the bracket on the transom to the left of the main outboard or rudder. Is my outboard long or short shaft? How Low Should a Motor Set on a Pontoon Boat? (Explained) 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. MarinePartsMan.com also says that V6 bass-boat engines have a 20-inch shaft. This is a measurement that has been used for BassCats, I'm maxMicroAmount: 0.0, This placement is not only recommended but it will give you the best performance compared to something that is too long or too short. 2 0 obj 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. 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. The cookie is used to store the user consent for the cookies in the category "Analytics". boats.com, 1221 Brickell Avenue, 23rd Floor, Miami, FL 33131, USA. What is a Transom Saver And Do I Need One? - Boat Safe Before we start measuring the outboard shaft length, lets get it clear about whats referring to when we talk about the outboard shaft length. Mounting the motor lower on the boat transom can create excessive spray, increase case drag, reduce underwater clearance, and negatively impact faster boats. These cookies help provide information on metrics the number of visitors, bounce rate, traffic source, etc. The transom in a boat today is a place to hang your outboard motor. brackets. The correct shaft length for your boat depends on a few factors. Doing so, will put the propeller right below the boat. 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 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). In the photo above, we've measured from the motor bracket to the top of Boats with extended transoms, brackets that extend the mounting bracket for the outboard motor behind the back of the boat, can use a higher outboard height. Displacement hulled vessels like sailboats and workboats can benefit from a little more space between the hull and cavitation plate, but not much. Picking the right shaft length is mostly a factor of the transom height or the back of the boat. For slower boats, its less critical to. (updated Boaters who consider going with a higher mount can see increased speeds. To do so, take a measurement from the very top to the very bottom of the transom in the precise center.

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