"brackets". How can you figure out what your transom angle is? 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. from the transom. As with anything, there are exceptions to the rule. If you are running a twin-engine setup, then measure the same distance from each clamping plate to the bottom of the hull. Brackets are also handy for boats that do not have flat transoms, like canoe-stern sailboats or fan-tailed motor vessels. AztH ^zv_ cT,E1K/rAB54| Recommended Engine Oil 2-Stroke Outboard Motor Oil. This provides seaworthiness and offers maximum protection from large seas. Learn More About Your Boats Systems By Joining The Born Again Boating Academy! steel ruler, etc. Its important to note that manufacturers call their models different things. Higher mounting decisions should be left to the professionals. Advertisement cookies are used to provide visitors with relevant ads and marketing campaigns. As summer approaches there will be more boaters taking to the water. This is a measurement that has been used for BassCats, I'm The pros and cons of properly . if (PayTomorrow) { } 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. Each one has a totally different effect on the boats performance. 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. Some fishing boats can handle the motor being underwater. How To Measure Outboard Motor Shaft Length [Long v Short] - Boating Hub 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. 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. 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. Boat Transom Heights - The Beginner's Guide | My Westshore Because of the increased friction, cavitation reduces efficiency. Take a long straight edge, (long carpenter's level or long ), Al Shields It doesnt matter if you have a fiberglass boat, bay boat, big or small boat. So from there, I will try to help out by asking questions about your boat such as what type it is and the length. Here we will guide you in how to get the right boat transom height. With a jack plate, you can mount it exactly where you want it. maxMicroAmount: 0.0, var ptScript = "https://cdn.paytomorrow.com/js/pt-mpe.min.js"; It can also improve the experience of driving a faster boat. As a result, the issue is whether my boat need a short shaft or long shaft motor. 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. disregard the "hooks" at the front of the The average transom angle is around 14 degrees. Next, measure from your centerline to where the outboard will be mounted on each side. As a yacht designer and boater, I prefer longer shafts. var interval = setInterval(function () { How to Measure a Boat Transom - Gone Outdoors 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. It is unsafe to have the engine block too close to the water on a low transom. I live for the weekends when I can go out on the water and escape the stress of life on land. The lowest point will likely be directly under your drain plug if youve got one. A2: Instead of changing to the short outboard shaft, you can try the Jack Plate first. Displacement hulled vessels like sailboats and workboats can benefit from a little more space between the hull and cavitation plate, but not much. Higher mounting decisions should be left to the professionals. Step 2 requires the propeller's radius (check the user manual and then the technical drawing). PDF Outboard shaft lengths and transoms - Boat Builder Central So how to measure outboard shaft length? The boater must also consider if the boat transomsupport is designed to bear the weight of a higher mount. Rebuilt - What You Need to Know, Lower Unit and Sterndrive Break-In Instructions. This illustration depicts four different outboard mounting height options (courtesy Mercury Marine). If you are looking to repower, they may be able to offer some sage advice. Get the latest updates on new products and upcoming sales, 2023 Marine Parts Warehouse Incorporated See When St. Peters Basketball Games Are Today! It is where the outboard is mounted, and some boat owners place the name of the boat. 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. boats.com is part of the Boats Group Network. Doing this can have adverse effects. https:/. However, with the outboard shaft length too short, meaning the prop is too close to the surface, the engine is likely to ventilate and therefore slip on acceleration or lose power. In the past, though, it housed the officers and captain of 17th, 18th and 19th century sailing ships. Many single-engine boats mount a smaller auxiliary motor for emergency use. Where Onboard a Boat is the Transom Located and More About Transom Heights A propeller operates based on the height of the transom. 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. Well, raising the outboard motor can be an easy task for you. 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. Since the length of the shaft of your outboard is associated with the size boat, smaller engines will generally have shorter shafts. 2019s List of the Best Recreational Pontoon Boats for Sale. brackets. The point where these measurements intersect is your centerline. Anything bigger than that your obviously going to need an extra long shaft. If so, send me an Will Charpentier is a writer who specializes in boating and maritime subjects. Not to measure boat speed, but to gauge the mounting height of the outboard motor on the boat transom. Tightening Torque for Engine. Actually there is no designated letter for short shaft. Other factors to consider when determining the mounting height of an outboard are related to performance. Installing a Kicker Motor Bracket - Gone Outdoors The boater must also consider if the boat transom support is designed to bear the weight of a higher mount. Add the two measurements and you get 6 1/2". 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? I mean, who wants to purchase something as expensive as an outboard to only realize you bought the wrong one. Copyright 1999-2023 Boats Group. 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. (3) Move horizontally across the chart until you hit the graph curve. and I'll explain it better, (or point you to someone that can help. However, the motor should not be raised more than 5 inches above the standard position. Measuring the shaft length can be done in various ways, but the most common way is by using a tape measure. Follow Westshore Marine & Leisure on Twitter! 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. You'll need a short shaft outboard if it's 15 or less than an inch shorter. <>/Metadata 127 0 R/ViewerPreferences 128 0 R>> s = d.createElement("link"); If your outboard motor height. }, 100); Expectedly, when the transom angle is zero, it means it is flat. Repowering your boat is one of the most expensive upgrades you can make. As mentioned above, the operation of the propeller relies on the transom height. Outboards designed for saltwater applications usually have longer shafts. resting on the transom if you had the motor all the way down on the boat The height of the boat transom dictates the size of the outboard motor. On this type of boat, if you are in doubt, default to the longer-shafted outboard. If your boat planes, pay extra attention to getting the shaft length as close to perfect as possible. Keep these numbers in mind if you ever have a need for a new outboard motor for your boat. The transom is the boats flat vertical part at the back. The distance between the ends of a transom is measured in inches. To do so, take a measurement from the very top to the very bottom of the transom in the precise center. maxTerm: 36, Knowing the width, height and depth of your transom allows you to make several important decisions when selecting or purchasing a new outboard. the aluminum plate on top of the transom), to the bottom of the motor To sum up, there is a simple calculator of the shaft length for outboard motors: Outboard Shaft Length = Transom Height +/- Factors. They keep water out of your prop and increase water pressure in the system. By clicking Accept, you consent to the use of ALL the cookies. Is my outboard long or short shaft? Engine Oil Type Genuine or Recommended 2str Engine Oil. 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. When the jet drive is on the motor, set the height so that the leading edge of the intake is flush with the boat bottom. endobj What Is Boat Transom Height? | Gone Outdoors | Your Adventure Awaits A long shaft engine requires a height of 20 and extra-long shaft engines will need a transom height of 25. document.getElementById('cloakd53b59933f6c3f2e8b59f1b4a6d41fa5').innerHTML = ''; Another important measurement is the transom angle. No one wants to have issues with a new transom or boat repairs. Generally, the anti-ventilation plate on most engines is aligned with the bottom of the vessel. #3. If you have a question or need additional information. 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. This is measured by the propeller shaft being parallel to the vessels bottom. However, there may be times when a boater strays away from these recommendations. The vertical distance between the interior of the clamp and the cavitation plate is the shaft length specified by the outboard manufacturer. This will be the Then finally test your outboard, if the mount is perfect. Look at the part of your motor that would be While this is the case there is certain saltwater motors that are extra extra long at 30 and 35 shaft. 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. Whats the best height for my boat motor? In the case of a dinghy or johnboat, this point may be the top of the transom. Other boats that need extra long shafts are: Read my other articles on outboard motors. Trimming in, trimming down, and trimming out are all terms that a beginning boater should learn. 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. Other boats that need long shafts are. These cookies help provide information on metrics the number of visitors, bounce rate, traffic source, etc. 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. Typical motor lengths include the following. 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. (Any measurement given as "off the transom" Youll also want to pay attention when youre in shallow water because your prop will be lower than normal. Figuring out how to measure motor height on a 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 cavitation plate is the horizontal surface of the lower unit immediately above the propeller. 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. Thats it. Industry standards dictate that for short shaft engines the transom height should be 15. This could also effect your travelling capabilities on the boat trailer. You reply, "Im not sure, I think its a long". It can also improve the experience of driving a faster boat. Simply start with the engine in idle, followed by trimming the motor out by one-half to full trim. 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. Always weigh the risks of making adjustments. Take your time and understand your boat and your entire transom. With the long side (22 1/2), place a carpenters square ) in opposition to the keel. Extra-extra long shafts are 30-inches long. Raising the motor increases the speed of the boat while decreasing the effort needed to turn the boat. However, you will need an understanding of how the degrees will alter the boats usability. Workboats, sailboats, and displacement-hulled boats fall into this category. One of the great things about an outboard motor is how versatile it is. The cookies is used to store the user consent for the cookies in the category "Necessary". Measure the area of the transom directly where the engine will be mounted. Outboard motors can be fitted to a variety of boats, so manufacturers have standardized their engines to go on virtually anything. The standard shaft length for most outboard engines less than 125 horsepower is 20 inches. 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}'); Doing so, will put the propeller right below the boat. Any questions? Beginning boaters should be aware of the boats measurements. Setting Height of Outboard Motor - YouTube To do so, measure from the stern (back) of the boat to the midpoint of the hull on both sides. Before we start measuring the outboard shaft length, lets get it clear about whats referring to when we talk about the outboard shaft length. However, the motor should not be raised more than 5 inches above the standard position. mpeSelector: ".pt-mpe", What Is a Transom? Where Onboard a Boat is It Located? help with shaft length for a kicker - iboats Boating Forums This cookie is set by GDPR Cookie Consent plugin. These cookies track visitors across websites and collect information to provide customized ads. Measure straight down to the lowest point on the hull. Copyright 2017 Dealer Spike All Rights Reserved. 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. Amazon has plate extensions to allow adjustments without buying a new motor: T-H Marine Jack Plate Extension. since 1986. Measure from the top of the transom to the bottom of the hull. If the height of the boat transom is off it can cause major issues. Save my name, email, and website in this browser for the next time I comment. addyd53b59933f6c3f2e8b59f1b4a6d41fa5 = addyd53b59933f6c3f2e8b59f1b4a6d41fa5 + 'vanssports' + '.' + 'com'; The transom angle is the vertical incline of the transom and is measured in degrees. Here we will guide you in how to get the right boat transom height. These cookies will be stored in your browser only with your consent. var addyd53b59933f6c3f2e8b59f1b4a6d41fa5 = 'info' + '@'; Remember, if you use a longer outboard shaft than you need you will be increasing your draft. 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. It is extremely important that the boater understands the significance of the transoms height. We also use third-party cookies that help us analyze and understand how you use this website. 12 Small Fishing Boat Accessories to Buy Today. What Types of Documents Can be Sent to your Kindle Library? straight edge on the top of the transom to "extend" it out Re: Dinghy with a long shaft motor? Buying a boat can be an exciting purchase. Then open up the clamp bucket. Each one has a totally different effect on the boats performance. Outboard Motor Shaft Length - LeeRoy's Ramblings Place the clubs bottom on the ground as though it were going to be used to strike a golf ball. These are vertically aligned so the boater can make adjustments. Outboard Motor Shaft Length: How do I measure? You dont have to be a mathematician to determine the correct boat transom angle. Commonly, the transom angle ranges from 0-30 degrees, with the average transom angle set at 14 degrees. All rights reserved. Follow Westshore Marine & Leisure on Wordpress! I believe 20 to 21 inches is the optimum length for a lengthy shaft. boats.com, 1221 Brickell Avenue, 23rd Floor, Miami, FL 33131, USA. 1 0 obj 3 0 obj This is simply a measurement taken from the top of the transom (top of var BCData = {"csrf_token":"d7ecb6b56891bb66aee12dbc01a80162b3ed582c1acbe30f16fc9f1b2abc362f"}; The faster your boat, the more critical it is to get the sizing just right. If it measures anywhere from 17" to around 22", then your going to want to go with a long shaft motor. Wherever the outboard clamping bracket is, use this as the basis for measurement. stream I show you how to consistently measure your prop to pad height. ensure that your measurement is accurate. Place the rulers end on the ground behind the club and let the club to rest on top of it. Any owner seeking the last bit of speed from an outboard-powered boat should grab a yard stick. Beefier jack plates can be fitted should a boater be looking to mount an outboard with a shorter shaft than their transom demands. Extra-long shafts are 25-inches long. The shaft length for outboard motors has nothing to do with the water line. 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 measure the transom height, measure from the center on for transom (rear of the boat). To achieve 35 mph with a 6 hp engine, the total weight is 135 lbs (boat motor fuel passengers). bracket. If you decide to make adjustments, please consult a marine engine dealer about the boatdesign.