how to measure transom height for outboard motor

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. One of the factors in determining the height of the outboard is the placement of the exhaust port on the lower unit of the outboard engine. Thats a fairly simple list of symptoms, but if your motor is too low, youll probably notice at least one of them. With a jack plate, you can mount it exactly where you want it. This is handy if youre shopping for second-hand outboards or looking to sell the one that came with your boat. If you have a question or need additional information,contact ustoday. 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. As you can see, the measurement is about 2 1/2". In lower mounting, the engine is set lower than the recommended standard. The cavitation plate is the horizontal surface of the lower unit immediately above the propeller. Check the literature about your model boat online, and you may be surprised to find that the number is published for you. This is somewhat similar to #2, in that you are again measuring with a Trimming in, trimming down, and trimming out are all terms that a beginning boater should learn. The transom is the back of the boat where the motor is hung. 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. (We wont go into name-calling here, but the actual term for the cavitation plate is an anti-ventilation plate.) Measure from there down to the top of the cavitation plate, also known as the anti-ventilation plate. An outboard motor can drive just about any sort of boat with proper mounting. If so, send me an height (that I'm aware of); probably the most common is: Any questions? See diagram below. You dont have to be a mathematician to determine the correct boat transom angle. Other factors to consider when determining the mounting height of an outboard are related to performance. Buying a boat can be an exciting purchase. Beefier jack plates can be fitted should a boater be looking to mount an outboard with a shorter shaft than their transom demands. In the second photo, we've measure down from the top of the Detwiler How to Measure Outboard Shaft Length: The Only Guide You Need In the past, though, it housed the officers and captain of 17th, 18th and 19th century sailing ships. Step 3: Add another 10 cm (4'') to the previous calculation for the final ideal shaft length. AztH ^zv_ cT,E1K/rAB54| Happy boating! A long shaft engine requires a height of 20 and extra-long shaft engines will need a transom height of 25. Wherever the outboard clamping bracket is, use this as the basis for measurement. Outboard Motor Shaft Length & HP to Boat Calculating 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. Whether your on a pontoon boat, fishing boat, or speedboat boating is always one of the best times you can have. A: The short answer is Yes. However, your boat will have slightly more drag which will reduce your maximum speed. How the outboard will sit on the back of the boat depends on how the transom is designed. It is extremely important that the boater understands the significance of the transoms height. It doesnt matter if you have a fiberglass boat, bay boat, big or small boat. The correct shaft length for your boat depends on a few factors. For really big boats, the biggest and baddest six- or eight-cylinder outboards can have extra-extra long shafts up to 30 inches. 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). Before we start measuring the outboard shaft length, lets get it clear about whats referring to when we talk about the outboard shaft length. Take the center measurement from the top to the bottom of the hull. How To Measure Outboard Motor Shaft Length [Long v Short] - Boating Hub If youre looking for a bracket that can handle motors of up to 10/15 horsepower, go no further. There You also might not be able to lift the outboard out of the water entirely for storage. What Is a Transom? Where Onboard a Boat is It Located? For boats equipped with a bracket, calculate the same measurement but based on the bracket and not the transom. LOYALHEARTDY Outboard Motor 6 HP 2-Stroke Inflatable Fishing Boat Increased RPM and additional horsepower feed the need for speed. Beginning boaters should be aware of the boats measurements. 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. This is the dimension you'll need when selecting a width for your outboard motor's mounting bracket. There is a simple test to see if your outboard motor is set at the best 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. By clicking Accept, you consent to the use of ALL the cookies. Long Shaft vs. Short Shaft Outboard (What Are the Differences?) endobj Trimming in, trimming down, and trimming out are all terms that a beginning boater should learn. 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. Proper Mounting Height for an Outboard - Gone Outdoors Youll also want to pay attention when youre in shallow water because your prop will be lower than normal. 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. 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. Repowering your boat is one of the most expensive upgrades you can make. Outboard Motor Shaft Length For Pontoon Boat - Survival Tech Shop Propshaft in var prefix = 'ma' + 'il' + 'to'; Simply start with the engine in idle, followed bytrimming the motor out by one-half to full trim. Raising an outboard higher on the transom can reduce drag and raise top speed. } This will ensure the best performance. Although the longer outboard shaft length can lead to lower speed and more drag, the boat can push a heavier load. The brackets can add 1 inch to the overall mounting height of the outboard. On the downside, a higher mount can interfere with the boaters steering capabilities. Allowing the propeller to pull water from underneath and push it out behind the boat. 7. How high exactly do you have to raise the transom?- - Outboard Jets 4 0 obj If it measures 15" or with in a inch of that you will need a short shaft outboard. These cookies track visitors across websites and collect information to provide customized ads. The motor is what powers the boat so the two go hand-in-hand. What is Transom Height? The Effects of Standard, Lower and Higher Mounting. "brackets". With it comes a lot of responsibility and new things to learn including boat maintenance and boat basics. All things considered, sticking with the industry standard is best for the beginner. h[0].appendChild(s); Shaft lengths are available in increments of 5. 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. clearInterval(interval); x\[D~OUCO6[j](l%ay <8cylY{.L2s#]~U6A|Wj]-oo|mubqY6wbY_|!>Z8(RB:RHeTzOGO_=~t\ Gear Oil Quantity 195ml(6.6 Fl.oz.) endobj 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. Here we will guide you in how to get the right boat transom height. The boater must also consider if the boat transomsupport is designed to bear the weight of a higher mount. Outboards designed for saltwater applications usually have longer shafts. s.setAttribute("href", "https://cdn.paytomorrow.com/css/pt-mpe.min.css"); ensure that your measurement is accurate. Industry standards dictate that for short shaft engines the transom height should be 15. They keep water out of your prop and increase water pressure in the system. Take your time and understand your boat and your entire transom. endobj Extra-long shafts are 25-inches long. Remember, if you use a longer outboard shaft than you need you will be increasing your draft. resting on the transom if you had the motor all the way down on the boat The average transom angle is around 14 degrees. This will keep the prop in the water when the boat pitches in waves, or hobby-horses. Like Westshore Marine & Leisure on Facebook! 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. The outboard comes with mounting holes and brackets. Higher mounting decisions should be left to the professionals. You may wonder how deep your prop should be in the water. Your at your local outboard dealer shopping for a new motor and the salesman hits you with the question, "short or long shaft?". Later in the article is an image that shows you exactly where to measure. The transom angle is the vertical incline of the transom and is measured in degrees. This was the height of my 225 Yamaha on my TR21 Other boats that need extra long shafts are: Read my other articles on outboard motors. If it measures between 17 and 22, you'll want to go with a long shaft motor. Over time, Boating Hub has grown into a resource for boating enthusiasts around world. Expectedly, when the transom angle is zero, it means it is flat. 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. It is extremely important that the boater understands the significance of the transom's height. Then test the boat and adjust the height, if necessary . 7. The height of the boat transom dictates the size of the outboard motor. To do so, take a measurement from the very top to the very bottom of the transom in the precise center. Long shafts are 20-inches long. up to the bottom of the motor brackets, (as in #1). With some boats I have a pretty good idea as to what length motor should be hung on them. Anything bigger than that your obviously going to need an extra long shaft. Other uncategorized cookies are those that are being analyzed and have not been classified into a category as yet. Attention: Remember to measure the outboard shaft length straight up and down instead of measuring along the transom. It is where the outboard is mounted, and some boat owners place the name of the boat. Mounting kicker motor - General Discussion Forum | In-Depth Outdoors As summer approaches there will be more boaters taking to the water. Again, make sure that you are measuring to the flat part of the brackets; measuring; you may have to "extend" the flat part of the This is simply a measurement taken from the top of the transom (top of I would ask you to go back and measure the transom of your boat. <> The amount of degrees the transom leans back from vertical is known as the transom angle. Your goal is to measure how the outboard will sit, so start from the clamping plate and follow the centerline of the hull. 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. s.setAttribute("rel", "stylesheet"); The pros and cons of properly . Analytical cookies are used to understand how visitors interact with the website. Simply start with the engine in idle, followed by trimming the motor out by one-half to full trim. A: The answer varies by boat, but here are some rules of thumb for matching a short shaft outboard to your boat. One of the main concerns is causing the engine to overheat if not enough water reaches the engine to keep it cool. There are instances where a lower mount may be okay. This cookie is set by GDPR Cookie Consent plugin. h[0].appendChild(s); The height of the boat transom dictates the size of the outboard motor. Engine Oil Mixing Ratio Fuel 50: Engine Oil 1. Most of the standard engined boats it takes shafts that are 15-30inches long. You can order an outboard in lengths ranging from 15 inches to 30 inches, depending on its power output and possible uses. manufacturer will recommend the outboard height according to the bracket shape and length. Height Measurement: Recommended Shaft Length: 14" - 17.25" 15" Shaft (Short) 17.25" - 19.5" Varies by application 19.5" - 22.5" I mean it is better to be safe than sorry, am I right? Will Charpentier is a writer who specializes in boating and maritime subjects. MPW eBay Store - Thousands of New OEM Old Stock Parts! Charles Plueddeman is Boats.com's outboard, trailer, and PWC expert. You reply, "Im not sure, I think its a long". 5/rC,aQhsK@Q. Top 10 Choices for Boaters, Mercury Introduces 600HP V12 Verado Outboard Engine, The Outboard Expert: Tohatsu Propane Outboard Engine. Step 2 requires the propeller's radius (check the user manual and then the technical drawing). If your outboard motor height. In the case of a dinghy or johnboat, this point may be the top of the transom. 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. Outboard shaft length plays a crucial role in the performance of your boat. Using your existing control box and gauges will save you quite a bit of money in the end. What Kind of Fuel Does Your Marine Engine Need? It also cuts into speed and fuel efficiency. Recommended Engine Oil 2-Stroke Outboard Motor Oil. mpeSelector: ".pt-mpe", Increased RPM and additional horsepower feed the need for speed. loadScript(ptScript); maxAmount: 6500.0, (616) 364-0666, On all contiguous US part orders over $100. An inch or two probably wont make a big difference, but any more than that will lead to trouble. It will ensure that the outboards trim will be effective, and it will save you gas too. Pretty easy to figure out but like I said its crucial to pairing a motor with a boat. The cookies is used to store the user consent for the cookies in the category "Necessary". s = d.createElement("script"); This email address is being protected from spambots. Any owner seeking the last bit of speed from an outboard-powered boat should grab a yard stick. 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. I show you how to consistently measure your prop to pad height. Eq*^?6R83e+j}UY.(M7k]~4g)g ~wmS{ O7t/o(W|X? document.getElementById('cloakd53b59933f6c3f2e8b59f1b4a6d41fa5').innerHTML = ''; The transom is the flat vertical section at the rear of the boat. 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. We also use third-party cookies that help us analyze and understand how you use this website. Doing this can have adverse effects. While this is the case there is certain saltwater motors that are extra extra long at 30. 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. These are vertically aligned so the boater can make adjustments. trimming the motor out by one-half to full trim. These are vertically aligned so the boater can make adjustments. Boats with more engine power and weight require longer shaft outboards for better balance. var ptScript = "https://cdn.paytomorrow.com/js/pt-mpe.min.js"; The height is approximately six inches higher than with a propeller. Another important measurement is the transom angle. 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. ), and place it on the bottom of the pad in the center. } 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. Ten years ago I bought my first boat. 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. Cavitation plates are used on the bottom components of boats to help them operate better. How do you measure a transom on an outboard motor? Next, measure from your centerline to where the outboard will be mounted on each side. These two measurements will give you the length of the shaft you need. The point where these measurements intersect is your centerline. I run a 9.9 Mercury Bigfoot 20" shaft off the swim platform of my 89 Trophy 2160. not sure that it's still used. bracket. The engine must be linked to the transom at the proper height for a propeller to best meet specific boating demands. var xmlHttp = new XMLHttpRequest(); of the "bullet" on your lower unit. C Cheaptoon Cadet Joined Aug 4, 2010 Messages 28 Aug 24, 2010 #4 Re: Motor height on pontoon? I would also recommend finding your maximum horsepower rating which is located on the yellow coast guard tag towards the back of your boat. Boat Transom Heights - The Beginner's Guide | My Westshore Or it can have an angle degree as high as 30. How to Raise Outboard Motor on Transom? - Raising the Outboard Motor All things considered, sticking with the industry standard is best for the beginner.