A: The short answer is Yes. Two years ago, I bought a Boston Whaler to fish off the coast. %PDF-1.7 Your goal is to measure how the outboard will sit, so start from the clamping plate and follow the centerline of the hull. xmlHttp.open('POST', 'https://bes.gcp.data.bigcommerce.com/nobot'); displayPrimeOffers: true, However, your boat will have slightly more drag which will reduce your maximum speed. You must be still in the blue about that matter. There are instances where a lower mount may be okay. 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. disregard the "hooks" at the front of the If so, send me an So how to measure outboard shaft length? 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. Pretty easy to figure out but like I said its crucial to pairing a motor with a boat. If the height of the boat transom is off it can cause major issues. The transom angle is the vertical incline of the transom and is measured in degrees. Place the clubs bottom on the ground as though it were going to be used to strike a golf ball. These cookies help provide information on metrics the number of visitors, bounce rate, traffic source, etc. Beginning boaters should be aware of the boats measurements. Generally, the anti-ventilation plate on most engines is aligned with the bottom of the vessel. Keep these numbers in mind if you ever have a need for a new outboard motor for your boat. 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. and I'll explain it better, (or point you to someone that can help. Expectedly, when the transom angle is zero, it means it is flat. Your at your local outboard dealer shopping for a new motor and the salesman hits you with the question, "short or long shaft?". You also might not be able to lift the outboard out of the water entirely for storage. There is a simple test to see if your outboard motor is set at the best height. Always weigh the risks of making adjustments. This was the height of my 225 Yamaha on my TR21 However, there may be times when a boater strays away from these recommendations. If you are running a twin-engine setup, then measure the same distance from each clamping plate to the bottom of the hull. 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. Be sure to measure carefully and research thoroughly before diving in. If you have a small boat with a 15 to 17 inch aft transom, youll most likely need a short shaft outboard. If your boat is newer and the manufacturer is still in business, you might also want to try to give them a call. This measurement is primarily designed for single motor propulsion. Industry standards dictate that for short shaft engines the transom height should be 15. How do you measure a transom on an outboard motor? The greater the number, the more the drive may sway (also called tuck under or negative trim). Having the cavitation plate too low will cause excess drag and reduced performance at high speeds. Then, you can pick the right engine. Or measure from the main engine prop up to the water line? (function () { (616) 364-0666, On all contiguous US part orders over $100. Oftentimes you will want to adjust the outboard shaft length in order to improve the boat performance such as speed. I hope this helps someone out in their search for a new or newer outboard this season. We also use third-party cookies that help us analyze and understand how you use this website. This is somewhat similar to #2, in that you are again measuring with a var h = d.getElementsByTagName("head"), To do so, you will want to measure at the exact center of the transom from the very top to the very bottom. With more than a decade of experience cruising the lakes in my Crestliner Grand Cayman pontoon boat and my Boston Whaler, I now want to share everything I've learned with my community here at Boating Hub. AztH ^zv_ cT,E1K/rAB54| 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. It is possible that the motor could hang low while transporting on the boat trailer causing future boat repairs. I would ask you to go back and measure the transom of your boat. 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 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. Place the rulers end on the ground behind the club and let the club to rest on top of it. (We wont go into name-calling here, but the actual term for the cavitation plate is an anti-ventilation plate.) A big NO. What is the Virtual Sundance Film Festival? The height of the boat transom dictates the size of the outboard motor. 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. 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. While this is the case there is certain saltwater motors that are extra extra long at 30 and 35 shaft. In lower mounting, the engine is set lower than the recommended standard. Here we will guide you in how to get the right boat transom height. Eq*^?6R83e+j}UY.(M7k]~4g)g ~wmS{ O7t/o(W|X? 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. The transom is the boats flat vertical part at the back. When the boat transom is too low, the motor could end up underwater. Now that you have a better understanding of boat transom heights its time to take out the ruler and get the perfect measurements. Mounting the outboard a little bit lower than the standard point could avoid the possible ventilation and slip on acceleration. Before we get started lets see what a boat transom is and what it does. 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. Read the following to get the optimal shaft length for outboard motors! To do so, take a measurement from the very top to the very bottom of the transom in the precise center. It is where the outboard is mounted, and some boat owners place the name of the boat. This transom saver will support the weight of your outboard throughout your road travel, steadily bracing it against the trailer frame to relieve your transom of the weight and impact from consistent bouncing. Again, make sure that you are measuring to the flat part of the brackets; To measure the transom height, measure from the center on for transom (rear of the boat). 2 0 obj 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. h[0].appendChild(s); Mounting the motor lower on the boat transom can create excessive spray, increase case drag, reduce underwater clearance, and negatively impact faster boats. gtag('js', new Date()); Beefier jack plates can be fitted should a boater be looking to mount an outboard with a shorter shaft than their transom demands. A retired ship captain, Charpentier holds a doctorate in applied ocean science and engineering. If you said something smaller than that, thats where it can get tricky. They operate as a planing surface, allowing your boat to climb to the top more quickly. 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. To sum up, there is a simple calculator of the shaft length for outboard motors: Outboard Shaft Length = Transom Height +/- Factors. Copyright 2017 Dealer Spike All Rights Reserved. Check out the full chart of the Mercury outboard model code and its features. #1: Height Simply start with the engine in idle, followed by trimming the motor out by one-half to full trim. Determining Your Boat Transom Angle The transom angle - commonly measured in degrees - is the transom's vertical inclination. The height of the boat transom dictates the size of the outboard motor. Then test the boat and adjust the height, if necessary . And thats usually the case since the electric outboards are designed with larger and more efficient propeller that needs longer shaft. Step 4. Measure from the top of the transom to the bottom of the hull. Variables to consider when determining the mounting height include the size and style of the boat and the length of the outboard motor's shaft. straight edge from the center of the pad, but this time you're measuring The boater must also consider if the boat transom support is designed to bear the weight of a higher mount. stream Charles Plueddeman is Boats.com's outboard, trailer, and PWC expert. All rights reserved. If you have an outboard motor, the distance from one end to another will be found on the side or on a label near its bottom. You reply, "Im not sure, I think its a long". priceSelector: ".price--withoutTax, span.price.price--withTax", 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. 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. Read the measurement on the transoms bottom. The height is approximately six inches higher than with a propeller. 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. The mounting height of an outboard motor can impact the speed and handling characteristics of the boat. Required fields are marked *. Whether you already own a boat or looking for your first watercraft we are here to service your needs. The motor is what powers the boat so the two go hand-in-hand. Plus, a low transom cut is an invitation for the water to flood the boat. 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 standard shaft length for most outboard engines less than 125 horsepower is 20 inches. 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. Its where the outboard motor is attached, and its also where some boat owners put the boats name. 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. <> Small motors built for sailboats might come in a unique configuration with an extremely long shaft since these are mounted higher off the water. But, how do you measure it? Before we start measuring the outboard shaft length, lets get it clear about whats referring to when we talk about the outboard shaft length. 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. function mpeInit() { In lower mounting, the engine is set lower than the recommended standard. This distance is very important to the performance of you boat. The clamp bracket is designed so that the engine's mounting height on the transom can be adjusted higher than standard. It is unsafe to have the engine block too close to the water on a low transom. This measurement would be the inches of These cookies ensure basic functionalities and security features of the website, anonymously. 4 0 obj However, the motor should not be raised more than 5 inches above the standard position. It was a 23-foot Crestliner Grand Cayman pontoon boat. Increased RPM and additional horsepower feed the need for speed. Save my name, email, and website in this browser for the next time I comment. resting on the transom if you had the motor all the way down on the boat Smaller boats may use adjustable jack plates that can be changed to fit any outboard. Owners of bass boats, RIBs, or offshore fishing boats need to get this right. mpeInit(); It doesnt matter if you have a fiberglass boat, bay boat, big or small boat. To do so, take a measurement from the very top to the very bottom of the transom in the precise center. All you need to do is measure how much to rise. The transom in a boat today is a place to hang your outboard motor. As summer approaches there will be more boaters taking to the water. Raising the motor increases the speed of the boat while decreasing the effort needed to turn the boat. Before we get started lets see what a boat transom is and what it does. It is extremely important that the boater understands the significance of the transoms height. Having the cavitation plate a bit lower than the transom is preferable to having it too high. The collapsing bubbles are loaded with extremely low-pressure water vapor, which causes damage to a variety of surfaces as they collapse. These are vertically aligned so the boater can make adjustments. It is possible that the motor could hang low while transporting on the boat trailer causing future boat repairs. With some boats I have a pretty good idea as to what length motor should be hung on them. 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. On the downside, a higher mount can interfere with the boaters steering capabilities. Knowing the width, height and depth of your transom allows you to make several important decisions when selecting or purchasing a new outboard. 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). It is extremely important that the boater understands the significance of the transoms height. This exhaust port should be about 1 inch above the water line when the boat is idling. s.setAttribute("type", "text/javascript"); To achieve this, the motor itself has to be attached at the correct height. trimming the motor out by one-half to full trim. If the height of the boat transom is off it can cause major issues. Some may call it a standard length while others may call it a short or a long shaft. However, there may be times when a boater strays away from these recommendations. Check the literature about your model boat online, and you may be surprised to find that the number is published for you. Another important measurement is the transom angle. Also, the boat will be more likely to hit bottom or submerge objects such as rocks or logs. 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). The clamp bracket on the latest Mercury Four-Stoke-model outboards has five mounting bolt holes spaced .75 inches apart. Copyright 1999-2023 Boats Group. Place the point of a yardstick at the middle of the top of the boat transom. Top 10 Choices for Boaters, Mercury Introduces 600HP V12 Verado Outboard Engine, The Outboard Expert: Tohatsu Propane Outboard Engine. 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. Trimming in, trimming down, and trimming out are all terms that a beginning boater should learn. A reversetransom that sits too high can impact the propellers of the motor and motor bracket. publicId: "32bf3437d1346295e03ebcf545f9c839", The amount of degrees the transom leans back from vertical is known as the transom angle. would be more accurate.) Check out some hot FAQs to help you get the proper outboard shaft lengths. As a result, the issue is whether my boat need a short shaft or long shaft motor. x\[D~OUCO6[j](l%ay <8cylY{.L2s#]~U6A|Wj]-oo|mubqY6wbY_|!>Z8(RB:RHeTzOGO_=~t\ The transom is the rear wall of the boat where the outboard engine is mounted in the middle. (In the case of the faster s = d.createElement("script"); It is where the outboard is mounted, and some boat owners place the name of the boat. If you decide to make adjustments, please consult a marine engine dealer about the boatdesign. Now that you have a better understanding of boat transom heights its time to take out the ruler and get the perfect measurements. out the confusion. If it measures anywhere from 17" to around 22", then your going to want to go with a long shaft motor. 1855 Alpine Avenue NWGrand Rapids, MI 49504This email address is being protected from spambots. Then open up the clamp bucket. However, youll notice a little increase in drag and a decrease in top-end performance. You'll need a short shaft outboard if it's 15 or less than an inch shorter. MPW eBay Store - Thousands of New OEM Old Stock Parts! jackplate to a point level with the top of the transom. 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. So how to determine the outboard shaft length? } As you can see, the measurement is about 2 1/2". 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. 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). 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. Lubrication System Engine Oil Mixed Gasoline. Engine Oil Type Genuine or Recommended 2str Engine Oil. Is my outboard long or short shaft? Recommended Engine Oil 2-Stroke Outboard Motor Oil. 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. With the motor trimmed so that the propshaft is parallel to the keel, the anti-ventilation plate should be just about even with your straight edge, and thus even with the boat bottom at the keel. Get the latest updates on new products and upcoming sales, 2023 Marine Parts Warehouse Incorporated 3 0 obj How to Measure Transom Height For vessels with transom-mounted outboards, you can easily figure out which type of outboard you need to get. Then adjust the motor in a higher hole with a flat head screwdriver. Check out the Westshore Marine & Leisure google plus page! It doesnt matter if you have a fiberglass boat, bay boat, big or small boat. The shaft length for outboard motors has nothing to do with the water line. The point where these measurements intersect is your centerline. It can also improve the experience of driving a faster boat. Well, raising the outboard motor can be an easy task for you. The boat transom can be flat with zero degree angles. 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. Height Measurement: Recommended Shaft Length: 14" - 17.25" 15" Shaft (Short) 17.25" - 19.5" Varies by application 19.5" - 22.5" If you decide to make some custom adjustments we have theexperience and know-howto make it happen. (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. But opting out of some of these cookies may affect your browsing experience. If you have a jackplate, you may have to get a bit creative in your You dont have to be a mathematician to determine the correct boat transomangle. The faster your boat, the more critical it is to get the sizing just right. 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. Each one has a totally different effect on the boats performance. Of course, its always best to go with standard practices when choosing thebest boat engine. This cookie is set by GDPR Cookie Consent plugin. The performance of these boats depends on quite a lot of factors, but getting the outboard length just right is an essential first step. 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. bassboat can be a bit confusing at times; hopefully this will help sort Doing this can have adverse effects. This cookie is set by GDPR Cookie Consent plugin. What are Apple Podcasts Subscriptions and Channels? Youll need a short shaft outboard if its 15 or less than an inch shorter. Generally, the anti-ventilation plate on most engines is aligned with the bottom of the vessel. But in many cases, its a little more complicated than that alone. Any questions? Next, measure from your centerline to where the outboard will be mounted on each side. This will ensure the best performance. Commonly, the transom angle ranges from 0-30 degrees, with the average transom angle set at 14 degrees. I also love helping others, which is why I created this website. If it measures between 17 and 22, youll want to go with a long shaft motor. maxAmount: 6500.0, This is measured by the propeller shaft being parallel to the vessels bottom. Youll also want to pay attention when youre in shallow water because your prop will be lower than normal. There are instances where a lower mount may be okay. 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. If you have a question or need additional information. A2: Instead of changing to the short outboard shaft, you can try the Jack Plate first. Use the mounting bracket on the motor to know where it will sit on the boat. Allowing the propeller to pull water from underneath and push it out behind the boat. You also have the option to opt-out of these cookies. Workboats, sailboats, and displacement-hulled boats fall into this category. 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}'); 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. since 1986. Happy boating! Industry standards dictate that for short shaft engines the transom height should be 15. For over five years he has worked as a newspaper reporter and historic researcher. Since the ventilation plate & foil are burried under water it is obviously too low. :$I>M W$h"%U_yzIb?]NHg_G|r@nX eTf."SQ 12 Small Fishing Boat Accessories to Buy Today. disregard the downward pointing "hooks" at the front of the Since the length of the shaft of your outboard is associated with the size boat, smaller engines will generally have shorter shafts. It does not store any personal data. There is a simple test to see if your outboard motor is set at the best height. 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. ), and place it on the bottom of the pad in the center. var ptScript = "https://cdn.paytomorrow.com/js/pt-mpe.min.js"; With a motor tote, the outboard and boat move as one, independently of the trailer, so there are no concerns about the boat shifting on the trailer, he says. Functional cookies help to perform certain functionalities like sharing the content of the website on social media platforms, collect feedbacks, and other third-party features. Mounting the outboard motor in accordance with the industry standards is important.
