Repowering your boat is one of the most expensive upgrades you can make. Anything bigger than that your obviously going to need an extra long shaft. Industry standards dictate that for short shaft engines the transom height should be 15. xmlHttp.setRequestHeader('Content-Type', 'application/json'); The transom angle is the vertical incline of the transom and is measured in degrees. 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. primeApr: 12.99, Among them will be first-timers or those who have recently purchased their boats. They operate as a planing surface, allowing your boat to climb to the top more quickly. The boater must also consider if the boat transomsupport is designed to bear the weight of a higher mount. Problems with getting the ventilation plate too low include slower hole-shot and lower top-end speeds. 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. The standard shaft length for most outboard engines less than 125 horsepower is 20 inches. publicId: "32bf3437d1346295e03ebcf545f9c839", August 9/08). The transom is the rear wall of the boat where the outboard engine is mounted in the middle. What the relationship to the pontoons is, I couldn't say. This restriction includes most fishing boats and longer sailboats. To do so, measure from the stern (back) of the boat to the midpoint of the hull on both sides. An outboard motor can drive just about any sort of boat with proper mounting. You dont have to be a mathematician to determine the correct boat transom angle. Boats that use longer outboard shafts include: And thats usually the case since the electric outboards are designed with larger and more efficient propeller that needs longer shaft. Extra-long shafts are 25-inches long. (1) Multiply the overall length of your boat (in feet) by it's widest beam at the stern (excluding any Fins and or Shear) (2) Locate that value on the left hand vertical column of the chart below. 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. Here we will guide you in how to get the right boat transom height. 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. A transom saver, which can change the spacing between the lower unit and the trailer, negates some of the support. Outboard motors can be fitted to a variety of boats, so manufacturers have standardized their engines to go on virtually anything. However, you will need an understanding of how the degrees will alter the boats usability. You can order an outboard in lengths ranging from 15 inches to 30 inches, depending on its power output and possible uses. 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. Whether you already own a boat or looking for your first watercraft we are here to service your needs. Here we will guide you in how to get the right boat transom height. Your goal is to measure how the outboard will sit, so start from the clamping plate and follow the centerline of the hull. This is a measurement that has been used for BassCats, I'm
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. want to measure from the transom to the flat part of this bracket,
Attention: Remember to measure the outboard shaft length straight up and down instead of measuring along the transom. }) } }); })(document); This is probably the worst case scenario out of the two. For vessels with transom-mounted outboards, you can easily figure out which type of outboard you need to get. This will keep the prop in the water when the boat pitches in waves, or hobby-horses. Add the two measurements and you get 6 1/2". Whats the best height for my boat motor? Doing this can have adverse effects. Boats with more engine power and weight require longer shaft outboards for better balance. 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. Commonly, the transom angle ranges from 0-30 degrees, with the average transom angle set at 14 degrees. The first order of business is to measure your boat for the ideal fit. Why wont Touch ID be under the screen in the iPhone 15 and iPhone 16? The clamp bracket is designed so that the engine's mounting height on the transom can be adjusted higher than standard. In lower mounting, the engine is set lower than the recommended standard. Again, make sure that you are measuring to the flat part of the brackets;
With a jack plate, you can mount it exactly where you want it. Of course, its always best to go with standard practices when choosing thebest boat engine. Now that you have a better understanding of boat transom heights its time to take out the ruler and get the perfect measurements. Raising the motor increases the speed of the boat while decreasing the effort needed to turn the boat. In extremes, the engine can have overheating problems if the boat is raised to a point where the water inlets for the cooling system are out of the water. 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. I mean, who wants to purchase something as expensive as an outboard to only realize you bought the wrong one. What are Apple Podcasts Subscriptions and Channels? })(); Necessary cookies are absolutely essential for the website to function properly. How Transom Height Is Measured Triton. var ptScript = "https://cdn.paytomorrow.com/js/pt-mpe.min.js"; The correct shaft length for your boat depends on a few factors. We use cookies on our website to give you the most relevant experience by remembering your preferences and repeat visits. It is where the outboard is mounted, and some boat owners place the name of the boat. It doesnt matter if you have a fiberglass boat, bay boat, big or small boat. The height of the boat transom dictates the size of the outboard motor. Its where the outboard motor is attached, and its also where some boat owners put the boats name. This alone can outweigh the negatives when deciding to adjust the mount upwards. By clicking Accept, you consent to the use of ALL the cookies. This, however, is not recommended for the beginning boater. s = d.createElement("link"); I hope this helps someone out in their search for a new or newer outboard this season. It can also improve the experience of driving a faster boat. This placement is not only recommended but it will give you the best performance compared to something that is too long or too short. 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. If you go too short your more than likely going to cavitate and loose power. The cookie is set by GDPR cookie consent to record the user consent for the cookies in the category "Functional". Attention: Remember to measure the outboard shaft length straight up and down instead of measuring along the transom. If you are running a twin-engine setup, then measure the same distance from each clamping plate to the bottom of the hull. 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. s.setAttribute("href", "https://cdn.paytomorrow.com/css/pt-mpe.min.css");
s.setAttribute("type", "text/javascript"); Boaters who consider going with a higher mount can see increased speeds. Ten years ago I bought my first boat. debugMode: false, What is the Virtual Sundance Film Festival? 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). Step 3: Add another 10 cm (4'') to the previous calculation for the final ideal shaft length. There are a series of four to six holes at the top of the bracket, and the lower bolts actually fit into slots. relation to pad
How the outboard will sit on the back of the boat depends on how the transom is designed. Higher mounting decisions should be left to the professionals. So you should just measure the height of the boat's transom from the center down to the lowest point of the hull, and compare transom height with the outboard shaft length numbers. The distance between the ends of a transom is measured in inches. A: The answer varies by boat, but here are some rules of thumb for matching a short shaft outboard to your boat. What Kind of Fuel Does Your Marine Engine Need? If you have a small boat with a 15 to 17 inch aft transom, youll most likely need a short shaft outboard. On the downside, a higher mount can interfere with the boaters steering capabilities. This website uses cookies to improve your experience while you navigate through the website. Propshaft in
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This cookie is set by GDPR Cookie Consent plugin. Will Charpentier is a writer who specializes in boating and maritime subjects. To do so, you will want to measure at the exact center of the transom from the very top to the very bottom. Eq*^?6R83e+j}UY.(M7k]~4g)g ~wmS{ O7t/o(W|X? 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. A yardstick will help you determine if your outboard engine is at the right height. Another important measurement is the transom angle. Save my name, email, and website in this browser for the next time I comment. Beyond motorboats designed for large outboards, you will see outboards hanging on the sterns of everything from small canoes to large cruising sailboats. However, there may be times when a boater strays away from these recommendations. The cookies is used to store the user consent for the cookies in the category "Necessary". brackets. Trimming in, trimming down, and trimming out are all terms that a beginning boater should learn. Over time, Boating Hub has grown into a resource for boating enthusiasts around world. (updated
boats.com, 1221 Brickell Avenue, 23rd Floor, Miami, FL 33131, USA. (3) Move horizontally across the chart until you hit the graph curve. 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. AztH
^zv_ cT,E1K/rAB54| not sure that it's still used. The center is the point where your outboard motor is (ideally) located. The performance of these boats depends on quite a lot of factors, but getting the outboard length just right is an essential first step. 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. Recommended Engine Oil 2-Stroke Outboard Motor Oil. There are instances where a lower mount may be okay. 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. Check out the Westshore Marine & Leisure Youtube page! If so, send me an
An inch or two probably wont make a big difference, but any more than that will lead to trouble. (616) 364-0666, On all contiguous US part orders over $100. function loadScript(script) { 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). For over five years he has worked as a newspaper reporter and historic researcher. As mentioned above, the operation of the propeller relies on the transom height. This could also affect your travelling capabilities on the boat trailer. But in many cases, its a little more complicated than that alone. A long shaft engine requires a height of 20 and extra-long shaft engines will need a transom height of 25. Place the point of a yardstick at the middle of the top of the boat transom. minAmount: 300.0, These two measurements will give you the length of the shaft you need. Mounting the outboard motor in accordance with the industry standards is important. 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. This is the dimension you'll need when selecting a width for your outboard motor's mounting bracket. 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. Place the clubs bottom on the ground as though it were going to be used to strike a golf ball. your motor will be higher.) var addy_textd53b59933f6c3f2e8b59f1b4a6d41fa5 = 'info' + '@' + 'vanssports' + '.' + 'com';document.getElementById('cloakd53b59933f6c3f2e8b59f1b4a6d41fa5').innerHTML += '
'+addy_textd53b59933f6c3f2e8b59f1b4a6d41fa5+'<\/a>'; If you are looking to repower, they may be able to offer some sage advice. Required fields are marked *. Among them will be first-timers or those who have recently purchased their boats. This is also known as the shaft length. A retired ship captain, Charpentier holds a doctorate in applied ocean science and engineering. But, how do you measure it? Expectedly, when the transom angle is zero, it means it is flat. Check out the full chart of the Mercury outboard model code and its features. It doesnt matter if you have a fiberglass boat, bay boat, big or small boat. Generally, the anti-ventilation plate on most engines is aligned with the bottom of the vessel. 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. Doing this can have adverse effects. What matters is the actual measurement in the specifications, not the name. *The Factors indicates the adjustment affected by on your boat type, the outboard working environment, and the transom distance as discussed above. The motor is what powers the boat so the two go hand-in-hand. It is possible that the motor could hang low while transporting on the boat trailer causing future boat repairs. 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. 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). #1: Height
} No one wants to have issues with a new transom or boat repairs. the propshaft below or above the pad. Before we get started lets see what a boat transom is and what it does. 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. For slower boats, its less critical to. center of the propshaft. It also cuts into speed and fuel efficiency. Learn More About Your Boats Systems By Joining The Born Again Boating Academy! Simply start with the engine in idle, followed by, If you decide to make some custom adjustments we have the. The same is true for the newest, high-powered offshore fishing boats, where triple or quadruple motor setups are becoming more and more common. %PDF-1.7
The prop will be in cleaner, harder water as it advances farther aft, making it more efficient. Knowing the width, height and depth of your transom allows you to make several important decisions when selecting or purchasing a new outboard. Take your time and understand your boat and your entire transom. For most boaters this is a no brainer, but for the novice or inexperienced boater it may be a tougher question. (function (d) { 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. Step 2: Three Variables to Consider Tightening Torque for Engine. If you have a question or need additional information,contact ustoday. This distance is very important to the performance of you boat. However, the motor should not be raised more than 5 inches above the standard position. Actually there is no designated letter for short shaft. Increased RPM and additional horsepower feed the need for speed. The collapsing bubbles are loaded with extremely low-pressure water vapor, which causes damage to a variety of surfaces as they collapse. Some outboards have a serial number that tells you which shaft length to go for. straight edge from the center of the pad, but this time you're measuring
will be to the flat part; if you measure to the bottom of the brackets
Or measure from the main engine prop up to the water line? 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. Save my name, email, and website in this browser for the next time I comment. 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. var h = d.getElementsByTagName("head"), You will also risk hitting bottom or submerge objects more frequently such as rocks or logs. This provides seaworthiness and offers maximum protection from large seas. 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. var path = 'hr' + 'ef' + '='; if (PayTomorrow) { actually have the propshaft above the pad.). In lower mounting, the engine is set lower than the recommended standard. What's the best height for my boat motor? logoColor: "original", 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. disregard the "hooks" at the front of the
It is unsafe to have the engine block too close to the water on a low transom. It also cuts into speed and fuel efficiency. 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. This email address is being protected from spambots. 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. Safely but briskly accelerate. The average transom angle is around 14 degrees. Your email address will not be published. Thats it. Take your time and understand your boat and your entire transom. You may wonder how deep your prop should be in the water. If it measures anywhere from 17" to around 22", then your going to want to go with a long shaft motor. 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. steel ruler, etc. The motor length corresponds to the transom height of the boat, measured from the keel to gunwale at the transom. The cookie is used to store the user consent for the cookies in the category "Analytics". Boat Transom Heights The Beginners Guide, Buying a boat can be an exciting purchase. It will ensure that the outboards trim will be effective, and it will save you gas too. var prefix = 'ma' + 'il' + 'to'; 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. They keep water out of your prop and increase water pressure in the system. To do so, you will want to measure at the exact center of the transom from the very top to the very bottom. 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. Boaters who consider going with a higher mount can see increased speeds. A deep Vee hull will result in a different measurement than a flatter . If it measures 15" or with in a inch of that you will need a short shaft outboard. If you decide to make some custom adjustments we have theexperience and know-howto make it happen. The propellers will also have trouble reaching the water. It moves an outboard up and down to optimize performance and enable a boat to venture into shallower water than it might otherwise. straight edge on the top of the transom to "extend" it out
This was the height of my 225 Yamaha on my TR21
Engine Oil Type Genuine or Recommended 2str Engine Oil. Most of the time, adding a hydrofoil to an outboard improves performance. This allows the engine to idle without the flow of the exhaust being restricted. Measure from the top of the transom to the bottom of the hull. A reverse transom that sits too high can impact the propellers of the motor and motor bracket. With it comes a lot of responsibility and new things to learn including boat maintenance and boat basics. clearInterval(interval); Top 10 Choices for Boaters, Mercury Introduces 600HP V12 Verado Outboard Engine, The Outboard Expert: Tohatsu Propane Outboard Engine. On the downside, a higher mount can interfere with the boaters steering capabilities. Long shafts are 20-inches long. Oftentimes you will want to adjust the outboard shaft length in order to improve the boat performance such as speed. You also have the option to opt-out of these cookies. Youll also want to pay attention when youre in shallow water because your prop will be lower than normal. storeDisplayName: "Marine Parts Warehouse", Actual shaft length is 21.5" on those. mpeInit(); Make sure that you are measuring straight up, at a 90 degree angle to
However, the shaft length for smaller boats could be long or short depending on its style, speed requirement, etc. Add yours in the comment and Ill get back to you asap. Other boats that need long shafts are. Should I take the raft onto the water and measure the exact distance from the top of the transom to the water line? I live for the weekends when I can go out on the water and escape the stress of life on land. However, the motor should not be raised more than 5 inches above the standard position. Boat hulls are designed in three basic types that range from slow displacement and semi-displacement hulls to the fastest planing hulls. hulls, such as Allisons, Bullets, Strokers, etc., this measurement could
The transom is the "back wall" of your boat, the most rearward part of your hull. Read the following to get the optimal shaft length for outboard motors! 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. The current measurement is the ventilation plate is about 1 1/2" above the true keel line which is about 24" in front of the motor edge. Copyright 1999-2023 Boats Group. A big NO. 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.