How do you measure a transom on an outboard motor? Two years ago, I bought a Boston Whaler to fish off the coast. 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. The lowest point will likely be directly under your drain plug if youve got one. Mounting the outboard motor in accordance with the industry standards is important. gtag('js', new Date()); However, youll notice a little increase in drag and a decrease in top-end performance. Rebuilt - What You Need to Know, Lower Unit and Sterndrive Break-In Instructions. Outboard motors can be fitted to a variety of boats, so manufacturers have standardized their engines to go on virtually anything. Take your time and understand your boat and your entire transom. 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. When mounting the engine, you want the cavitation plate to be 1 above the boat bottom for every 12 away from the transom. Using your existing control box and gauges will save you quite a bit of money in the end. I would also recommend finding your maximum horsepower rating which is located on the yellow coast guard tag towards the back of your boat. Because of the increased friction, cavitation reduces efficiency. We use cookies on our website to give you the most relevant experience by remembering your preferences and repeat visits. })(); 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. }, 100); PayTomorrow.mpeInit({ The amount of degrees the transom leans back from vertical is known as the transom angle. enableMoreInfoLink: true, So how to determine the outboard shaft length? The outboard comes with mounting holes and brackets. Extra-extra long shafts are 30-inches long. Boaters who consider going with a higher mount can see increased speeds. It also cuts into speed and fuel efficiency. MarinePartsMan.com also says that V6 bass-boat engines have a 20-inch shaft. and I'll explain it better, (or point you to someone that can help. This alone can outweigh the negatives when deciding to adjust the mount upwards. This could also affect your travelling capabilities on the boat trailer. 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. Other boats that need long shafts are. Keep these numbers in mind if you ever have a need for a new outboard motor for your boat. var addyd53b59933f6c3f2e8b59f1b4a6d41fa5 = 'info' + '@'; Since the ventilation plate & foil are burried under water it is obviously too low. <>/Metadata 127 0 R/ViewerPreferences 128 0 R>> The boater must also consider if the boat transom support is designed to bear the weight of a higher mount. xmlHttp.open('POST', 'https://bes.gcp.data.bigcommerce.com/nobot'); This placement is not only recommended but it will give you the best performance compared to something that is too long or too short. Simply start with the engine in idle, followed bytrimming the motor out by one-half to full trim. Your at your local outboard dealer shopping for a new motor and the salesman hits you with the question, "short or long shaft?". Out of these, the cookies that are categorized as necessary are stored on your browser as they are essential for the working of basic functionalities of the website. steel ruler, etc. The mounting height of an outboard motor can impact the speed and handling characteristics of the boat. Remember, if you use a longer outboard shaft than you need you will be increasing your draft. Buying a boat can be an exciting purchase. This could also effect your travelling capabilities on the boat trailer. 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. MPW eBay Store - Thousands of New OEM Old Stock Parts! x\[D~OUCO6[j](l%ay <8cylY{.L2s#]~U6A|Wj]-oo|mubqY6wbY_|!>Z8(RB:RHeTzOGO_=~t\ I show you how to consistently measure your prop to pad height. As with anything, there are exceptions to the rule. I live for the weekends when I can go out on the water and escape the stress of life on land. However, there may be times when a boater strays away from these recommendations. Necessary cookies are absolutely essential for the website to function properly. loadScript(ptScript); Here we will guide you in how to get the right boat transom height. function mpeInit() { If your boat planes, pay extra attention to getting the shaft length as close to perfect as possible. Whether you already own a boat or looking for your first watercraft we are here to service your needs. 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. ), and place it on the bottom of the pad in the center. }) } }); })(document); Gear Oil Quantity 195ml(6.6 Fl.oz.) Before we get started lets see what a boat transom is and what it does. Save my name, email, and website in this browser for the next time I comment. Repowering your boat is one of the most expensive upgrades you can make. With some boats I have a pretty good idea as to what length motor should be hung on them. Tightening Torque for Engine. Boat transomangles play a pivotal role in the flexibility of the boats trimming abilities. All you need to do is measure how much to rise. If it measures between 17 and 22, youll want to go with a long shaft motor. However, you will need an understanding of how the degrees will alter the boats usability. 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. Also, the boat will be more likely to hit bottom or submerge objects such as rocks or logs. The Effects of Standard, Lower and Higher Mounting. out the confusion. You may wonder how deep your prop should be in the water. The point where these measurements intersect is your centerline. 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. However, the motor should not be raised more than 5 inches above the standard position. 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. You can find your Mercury outboard model code on an ID plate or sticker. 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. Before we get started lets see what a boat transom is and what it does. C Cheaptoon Cadet Joined Aug 4, 2010 Messages 28 Aug 24, 2010 #4 Re: Motor height on pontoon? If so, send me an Basically, there are three main ways to measure motor For really big boats, the biggest and baddest six- or eight-cylinder outboards can have extra-extra long shafts up to 30 inches. The faster your boat, the more critical it is to get the sizing just right. In lower mounting, the engine is set lower than the recommended standard. 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. If you decide to make adjustments, please consult a marine engine dealer about the boatdesign. A long shaft engine requires a height of 20 and extra-long shaft engines will need a transom height of 25. The boat transom can be flat with zero degree angles. The cookie is set by GDPR cookie consent to record the user consent for the cookies in the category "Functional". It can also improve the experience of driving a faster boat. It is unsafe to have the engine block too close to the water on a low transom. clearInterval(interval); Tilt your motor until the bullet of the gearcase is This measurement is primarily designed for single motor propulsion. Smaller boats may use adjustable jack plates that can be changed to fit any outboard. 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. Triton. There is a simple test to see if your outboard motor is set at the best height. Knowing the width, height and depth of your transom allows you to make several important decisions when selecting or purchasing a new outboard. It doesnt matter if you have a fiberglass boat, bay boat, big or small boat. Save my name, email, and website in this browser for the next time I comment. Also, how do you determine the length of an outboard transom? resting on the transom if you had the motor all the way down on the boat actually have the propshaft above the pad.). Here we look at the effects of standard, lower and higher mounting. h[0].appendChild(s); As mentioned above, the operation of the propeller relies on the transom height. var prefix = 'ma' + 'il' + 'to'; Which Navigation Lights Does Your Boat Need? Over time, Boating Hub has grown into a resource for boating enthusiasts around world. the propshaft below or above the pad. In the second photo, we've measure down from the top of the Detwiler However, there may be times when a boater strays away from these recommendations. Your email address will not be published. Expectedly, when the transom angle is zero, it means it is flat. 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). The performance of these boats depends on quite a lot of factors, but getting the outboard length just right is an essential first step. 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. 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. Place the clubs bottom on the ground as though it were going to be used to strike a golf ball. Check out the full chart of the Mercury outboard model code and its features. Safely but briskly accelerate. If the propeller fails to ventilate, the motor is mounted to low. I mean, who wants to purchase something as expensive as an outboard to only realize you bought the wrong one. Actual shaft length is 21.5" on those. With this in mind, how can I determine if my outboard has a short or long shaft? The cookie is used to store the user consent for the cookies in the category "Analytics". (In the case of the faster s = d.createElement("link"); This measurement would be the inches of If you decide to make adjustments, please consult a marine engine dealer about the boat design. Other uncategorized cookies are those that are being analyzed and have not been classified into a category as yet. 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. Plus, a low transom cut is an invitation for the water to flood the boat. 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. The height of the boat transom dictates the size of the outboard motor. The outboard comes with mounting holes and brackets. 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. Read the following to get the optimal shaft length for outboard motors! The boat transom can be flat with zero degree angles. This is simply a measurement taken from the top of the transom (top of This would not be a good thing. Among them will be first-timers or those who have recently purchased their boats. This cookie is set by GDPR Cookie Consent plugin. Mounting the motor lower on the boat transom can create excessive spray, increase case drag, reduce underwater clearance, and negatively impact faster boats. Workboats, sailboats, and displacement-hulled boats fall into this category. High powered boats usually only come in long and extra-long variants. If it measures anywhere from 17" to around 22", then your going to want to go with a long shaft motor. The transom angle is the vertical incline of the transom and is measured in degrees. The propellers will also have trouble reaching the water. Attention: Remember to measure the outboard shaft length straight up and down instead of measuring along the transom. The most common percent angle is probably 12, however spec sheets for O/B and I/O boats may show 10 percent, 12 percent, and 14 degrees. since 1986. It doesnt matter if you have a fiberglass boat, bay boat, big or small boat. If the height of the boat transom is off it can cause major issues. If you said something smaller than that, thats where it can get tricky. The transom is the flat vertical section at the rear of the boat. window.dataLayer = window.dataLayer || []; There is a simple test to see if your outboard motor is set at the best height. 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. Some boats are equipped with transom-hung outboards while others have a bracket. Most transom savers can support up to a 150HP motor, which is sufficient for most regular boats. Then, you can pick the right engine. One of the main concerns is causing the engine to overheat if not enough water reaches the engine to keep it cool. The height of the boat transom dictates the size of the outboard motor. 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. 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. All rights reserved. How to Buy a Boat: Tips for a First Time Buyer, Top 10 New Fishing Boats for Under $20,000, What Type is Right for You? Its important to note that manufacturers call their models different things. A transom saver, which can change the spacing between the lower unit and the trailer, negates some of the support. It does not store any personal data. Follow Westshore Marine & Leisure on Twitter! <> 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. debugMode: false, Place the rulers end on the ground behind the club and let the club to rest on top of it. Generally, the anti-ventilation plate on most engines is aligned with the bottom of the vessel. 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. Amazon has plate extensions to allow adjustments without buying a new motor: T-H Marine Jack Plate Extension. 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.