It was a 23-foot Crestliner Grand Cayman pontoon boat. 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. All things considered, sticking with the industry standard is best for the beginner. Copyright 2017 Dealer Spike All Rights Reserved. This cookie is set by GDPR Cookie Consent plugin. Some may call it a standard length while others may call it a short or a long shaft. The height of the boat transom dictates the size of the outboard motor. Use the mounting bracket on the motor to know where it will sit on the boat. A reverse transom that sits too high can impact the propellers of the motor and motor bracket. These cookies help provide information on metrics the number of visitors, bounce rate, traffic source, etc. mpeInit(); For example, you can have the Mercury outboard shaft length by model code. 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. The prop will be in cleaner, harder water as it advances farther aft, making it more efficient. publicId: "32bf3437d1346295e03ebcf545f9c839", <> Actually there is no designated letter for short shaft. Some fishing boats can handle the motor being underwater. PayTomorrow.mpeInit({ These allow the mounting of a standard length outboard behind the transom. The height of the boat transom dictates the size of the outboard motor. Among them will be first-timers or those who have recently purchased their boats. 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. If you have a small boat with a 15 to 17 inch aft transom, youll most likely need a short shaft outboard. maxTerm: 36, 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. August 9/08). As you can see, the measurement is about 2 1/2". Determining Your Boat Transom Angle The transom angle - commonly measured in degrees - is the transom's vertical inclination. xmlHttp.open('POST', 'https://bes.gcp.data.bigcommerce.com/nobot'); As a result, the issue is whether my boat need a short shaft or long shaft motor. Measure from there down to the top of the cavitation plate, also known as the anti-ventilation plate. Chances are the boat was designed with a specific size of outboard in mind. the aluminum plate on top of the transom), to the bottom of the motor You dont have to be a mathematician to determine the correct boat transom angle. Triton. What is Transom Height? Whether your on a pontoon boat, fishing boat, or speedboat boating is always one of the best times you can have. A reversetransom that sits too high can impact the propellers of the motor and motor bracket. Although the longer outboard shaft length can lead to lower speed and more drag, the boat can push a heavier load. Doing so, will put the propeller right below the boat. endobj It is extremely important that the boater understands the significance of the transoms height. To do so, you will want to measure at the exact center of the transom from the very top to the very bottom. This, however, is not recommended for the beginning boater. #2. (function (d) { Outboard shaft length plays a crucial role in the performance of your boat. How can you figure out what your transom angle is? But, how do you measure it? However, the shaft length for smaller boats could be long or short depending on its style, speed requirement, etc. With such an important, long-term, and expensive upgrade, its never a bad idea to double-check. If it measures between 17 and 22, youll want to go with a long shaft motor. Outboards designed for saltwater applications usually have longer shafts. Generally, the anti-ventilation plate on most engines is aligned with the bottom of the vessel. Step 2 requires the propeller's radius (check the user manual and then the technical drawing). Commonly, the transom angle ranges from 0-30 degrees, with the average transom angle set at 14 degrees. 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. This placement is not only recommended but it will give you the best performance compared to something that is too long or too short. See diagram below. 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. We use cookies on our website to give you the most relevant experience by remembering your preferences and repeat visits. Say the 20 shaft is a long shaft length for gas engines, but it is a short shaft length for electric outboard motors. 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. The cookie is used to store the user consent for the cookies in the category "Other. Since the length of the shaft of your outboard is associated with the size boat, smaller engines will generally have shorter shafts. 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. There are instances where a lower mount may be okay. Lastly, knowing the year of your motor and what style of controls you have (side mount, concealed side mount, or binnacle) is also a plus because it will tell the dealer if your current controls are compatible with the motor you are purchasing. In addition, motor totes will not harm the finish of the lower unit. How do you measure a transom on an outboard motor? The transom is the flat vertical section at the rear of the boat. 1855 Alpine Avenue NWGrand Rapids, MI 49504This email address is being protected from spambots. 1 0 obj If the propeller fails to ventilate, the motor is mounted to low. a Detwiler manual jackplate. What is the Virtual Sundance Film Festival? One of the main concerns is causing the engine to overheat if not enough water reaches the engine to keep it cool. If you are running a twin-engine setup, then measure the same distance from each clamping plate to the bottom of the hull. AztH ^zv_ cT,E1K/rAB54| Other uncategorized cookies are those that are being analyzed and have not been classified into a category as yet. to where the brackets were actually resting on the transom. 7. Some fishing boats can handle the motor being underwater. }, 100); To do so, take a measurement from the very top to the very bottom of the transom in the precise center. In the case of a larger offshore boat, it may be to the top of a cutout on the . xmlHttp.setRequestHeader('Content-Type', 'application/json'); %PDF-1.7 center of the propshaft. This is handy if youre shopping for second-hand outboards or looking to sell the one that came with your boat. What the relationship to the pontoons is, I couldn't say. Its important to note that manufacturers call their models different things. 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. Actual shaft length is 21.5" on those. Outboard Motor Shaft Length: How do I measure? (updated Here we will guide you in how to get the right boat transom height. Shaft lengths are available in increments of 5. storeDisplayName: "Marine Parts Warehouse", 5/rC,aQhsK@Q. This is measured by the propeller shaft being parallel to the vessels bottom. Boat transomangles play a pivotal role in the flexibility of the boats trimming abilities. This would not be a good thing. With it comes a lot of responsibility and new things to learn including, Why your boat transom needs to be the right height, The pros and cons of properly mounting the outboard motor to the transom, Standard mounting is always best for the beginner, Of course, its always best to go with standard practices when choosing the, Lower mounting is not for the beginning boater, Mounting the motor lower on the boat transom, There is a simple test to see if your outboard motor is set at the best height. <>/ExtGState<>/XObject<>/ProcSet[/PDF/Text/ImageB/ImageC/ImageI] >>/MediaBox[ 0 0 595.2 841.8] /Contents 4 0 R/Group<>/Tabs/S/StructParents 0>> Or it can have an angle degree as high as 30. This could also effect your travelling capabilities on the boat trailer. Check out the Westshore Marine & Leisure google plus page! endobj Long shafts are 20-inches long. This measurement would be the inches of All rights reserved. It moves an outboard up and down to optimize performance and enable a boat to venture into shallower water than it might otherwise. If so, send me an 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. 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. 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. Basically, there are three main ways to measure motor height (that I'm aware of); probably the most common is: # 1: Height of the motor off the transom This is simply a measurement taken from the top of the transom (top of the aluminum plate on top of the transom), to the bottom of the motor "brackets". Other factors to consider when determining the mounting height of an outboard are related to performance. <>/Metadata 127 0 R/ViewerPreferences 128 0 R>> The form of a boats transom varies depending on the manufacturer and model. if (PayTomorrow) { At least if its too long you can raise the motor or "build up" your transom. Check out the full chart of the Mercury outboard model code and its features. (Putting a Some outboards have a serial number that tells you which shaft length to go for. Knowing how this can affect the overall operation of the boat is a factor to be considered. 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 point where these measurements intersect is your centerline. Will Charpentier is a writer who specializes in boating and maritime subjects. Doing this can have adverse effects. Any questions? of the motor off the transom Whats the best height for my boat motor? It is where the outboard is mounted, and some boat owners place the name of the boat. 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. 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. Remember, if you use a longer outboard shaft than you need you will be increasing your draft. 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. I mean, who wants to purchase something as expensive as an outboard to only realize you bought the wrong one. If the propeller fails to ventilate, the motor is mounted to low. Follow Westshore Marine & Leisure on Twitter! Plus, a low transom cut is an invitation for the water to flood the boat. Set the end of the tape on the outside edge of the taffrail at the center and measure inward to the inside edge of the taffrail. var prefix = 'ma' + 'il' + 'to'; Analytical cookies are used to understand how visitors interact with the website. Other boats that need extra long shafts are: Read my other articles on outboard motors. s = d.createElement("script"); 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. Outboard motors can be fitted to a variety of boats, so manufacturers have standardized their engines to go on virtually anything. Well, raising the outboard motor can be an easy task for you. There is a simple test to see if your outboard motor is set at the best height. The cookie is used to store the user consent for the cookies in the category "Performance". Measure from the top of the straight edge to the center of the front 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. steel ruler, etc. Where Onboard a Boat is the Transom Located and More About Transom Heights A propeller operates based on the height of the transom. Extra-long shafts are 25-inches long. Or it can have an angle degree as high as 30. The vertical distance between the interior of the clamp and the cavitation plate is the shaft length specified by the outboard manufacturer. d.addEventListener("DOMContentLoaded", function (e) { Again, make sure that you are measuring to the flat part of the brackets; 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. 2019s List of the Best Recreational Pontoon Boats for Sale. 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. We also use third-party cookies that help us analyze and understand how you use this website. This cookie is set by GDPR Cookie Consent plugin. Increased RPM and additional horsepower feed the need for speed. No one wants to have issues with a new transom or boat repairs. Two years ago, I bought a Boston Whaler to fish off the coast. For most boaters this is a no brainer, but for the novice or inexperienced boater it may be a tougher question. However, your boat will have slightly more drag which will reduce your maximum speed. priceSelector: ".price--withoutTax, span.price.price--withTax", Brackets are also handy for boats that do not have flat transoms, like canoe-stern sailboats or fan-tailed motor vessels. How the outboard will sit on the back of the boat depends on how the transom is designed. 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. Then test the boat and adjust the height, if necessary . Finding the right size is a matter of looking at what youve got and taking out the measuring tape. I hope this helps someone out in their search for a new or newer outboard this season. Attention: Remember to measure the outboard shaft length straight up and down instead of measuring along the transom. minAmount: 300.0, Your goal is to measure how the outboard will sit, so start from the clamping plate and follow the centerline of the hull. parallel with the straight edge. It is possible that the motor could hang low while transporting on the boat trailer causing future boat repairs. Because of the increased friction, cavitation reduces efficiency. What Kind of Fuel Does Your Marine Engine Need? When trimming your motor, they provide you a greater bow response. If you have a jackplate, you may have to get a bit creative in your 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 alone can outweigh the negatives when deciding to adjust the mount upwards. #1: Height 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. primeApr: 12.99, The pros and cons of properly . Then finally test your outboard, if the mount is perfect. The height of the boat transom dictates the size of the outboard motor. With a jack plate, you can mount it exactly where you want it. s = d.createElement("link"); The Effects of Standard, Lower and Higher Mounting. Simply start with the engine in idle, followed by trimming the motor out by one-half to full trim. Attention: Remember to measure the outboard shaft length straight up and down instead of measuring along the transom. straight edge on the top of the transom to "extend" it out % This illustration depicts four different outboard mounting height options (courtesy Mercury Marine). 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. If it measures anywhere from 17" to around 22", then your going to want to go with a long shaft motor. Top 10 Choices for Boaters, Mercury Introduces 600HP V12 Verado Outboard Engine, The Outboard Expert: Tohatsu Propane Outboard Engine. C Cheaptoon Cadet Joined Aug 4, 2010 Messages 28 Aug 24, 2010 #4 Re: Motor height on pontoon? Hold the tape on the top, center of the taffrail and measure straight down to the point, usually a sharp angle, where the transom joins the bottom of the boat. The collapsing bubbles are loaded with extremely low-pressure water vapor, which causes damage to a variety of surfaces as they collapse. As with anything, there are exceptions to the rule. 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. endobj 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). Take your time and understand your boat and your entire transom. However, you will need an understanding of how the degrees will alter the boats usability. On the downside, a higher mount can interfere with the boaters steering capabilities. (function () { Smaller inflatables and dinghies needshort shaft motors, whilst bigger boats require long or, in some circumstances, extreme long shaft versions. With it comes a lot of responsibility and new things to learn includingboat maintenanceand boat basics. Rest the yard stick or another suitable straight edge along the keel on the bottom of the boat so that it makes a straight line aft to the outboard. What matters is the actual measurement in the specifications, not the name. Your at your local outboard dealer shopping for a new motor and the salesman hits you with the question, "short or long shaft?". Most of the time, adding a hydrofoil to an outboard improves performance. The pressure behind your hand dropped as you slid your hand back and forth through the water. 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. Spark Plug 25.0nm(18.4 Ft-lb) (2.55 Kgf-m) The cavitation plate is the horizontal surface of the lower unit immediately above the propeller. They keep water out of your prop and increase water pressure in the system. If you went too long it would still work but it may lack in performance. The general guideline for longer shaft outboards is that the transom height should be at least 20 inches (50,8cm) above the waterline. 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. Each one has a totally different effect on the boats performance. 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 things considered, sticking with the industry standard is best for the beginner. You also might not be able to lift the outboard out of the water entirely for storage. from the transom. Of course, its always best to go with standard practices when choosing thebest boat engine. enableMoreInfoLink: true, You will also risk hitting bottom or submerge objects more frequently such as rocks or logs. Gear case sits just below or at the hull depth due to the deep v. manufacturer will recommend the outboard height according to the bracket shape and length. Ill also explain the difference between short and long shafts and how they vary by type of boat. Measure the area of the transom directly where the engine will be mounted. Picking the right shaft length is mostly a factor of the transom height or the back of the boat. It can also improve the experience of driving a faster boat. 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. It does not store any personal data. var addyd53b59933f6c3f2e8b59f1b4a6d41fa5 = 'info' + '@'; The engine must be linked to the transom at the proper height for a propeller to best meet specific boating demands. 12 Small Fishing Boat Accessories to Buy Today. 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}'); Save my name, email, and website in this browser for the next time I comment. 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. Your goal is to measure how the outboard will sit, so start from the clamping plate and follow the centerline of the hull. Simply start with the engine in idle, followed bytrimming the motor out by one-half to full trim. Rebuilt - What You Need to Know, Lower Unit and Sterndrive Break-In Instructions. Many single-engine boats mount a smaller auxiliary motor for emergency use. 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. 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. You must be still in the blue about that matter. s.setAttribute("type", "text/javascript"); Now that you have a better understanding of boat transom heights its time to take out the ruler and get the perfect measurements. The cookie is used to store the user consent for the cookies in the category "Analytics". logoColor: "original", Check the literature about your model boat online, and you may be surprised to find that the number is published for you. It can also improve the experience of driving a faster boat. Step 3: Add another 10 cm (4'') to the previous calculation for the final ideal shaft length. Some boats are equipped with transom-hung outboards while others have a bracket. 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. will be to the flat part; if you measure to the bottom of the brackets As mentioned above, the operation of the propeller relies on the transom height. out the confusion. The shaft length for outboard motors has nothing to do with the water line. Later in the article is an image that shows you exactly where to measure. ), Al Shields Happy boating! Buying a boat can be an exciting purchase. All boats are different, and the motor manufacturers produce a variety of standard lengths. Other boats that need long shafts are. Wherever the outboard clamping bracket is, use this as the basis for measurement. These two measurements will give you the length of the shaft you need. Boaters who consider going with a higher mount can see increased speeds. To achieve 35 mph with a 6 hp engine, the total weight is 135 lbs (boat motor fuel passengers). stream If mounting directly to a boat transom: Measure from the top of the transom down to the bottom of the hull or keel (lowest point). The transom angle is the vertical incline of the transom and is measured in degrees. 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. Mounting the motor lower on the boat transom can create excessive spray, increase case drag, reduce underwater clearance, and negatively impact faster boats. The boater must also consider if the boat transom support is designed to bear the weight of a higher mount. Thats it. The outboard comes with mounting holes and brackets. addyd53b59933f6c3f2e8b59f1b4a6d41fa5 = addyd53b59933f6c3f2e8b59f1b4a6d41fa5 + 'vanssports' + '.' + 'com';