and I'll explain it better, (or point you to someone that can help. To do so, you will want to measure at the exact center of the transom from the very top to the very bottom. 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. Youll also want to pay attention when youre in shallow water because your prop will be lower than normal. Simply start with the engine in idle, followed by trimming the motor out by one-half to full trim. #3. ), Al Shields 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. This is simply a measurement taken from the top of the transom (top of As a yacht designer and boater, I prefer longer shafts. In the photo above, we've measured from the motor bracket to the top of With such an important, long-term, and expensive upgrade, its never a bad idea to double-check. (Any measurement given as "off the transom" Offshore vessels are often equipped with a large mounting bracket so that the transom can be left at full height. For over five years he has worked as a newspaper reporter and historic researcher. And the rule of thumb is that you should keep the cavitation plate level with the bottom or keel of the boat. Outboard motors can be fitted to a variety of boats, so manufacturers have standardized their engines to go on virtually anything. This is the dimension you'll need when selecting a width for your outboard motor's mounting bracket. This measurement is primarily designed for single motor propulsion. A2: Instead of changing to the short outboard shaft, you can try the Jack Plate first. This is also known as the shaft length. Why wont Touch ID be under the screen in the iPhone 15 and iPhone 16? This restriction includes most fishing boats and longer sailboats. Place the bracket on the transom to the left of the main outboard or rudder. jackplate to a point level with the top of the transom. The height of the boat transom dictates the size of the outboard motor. 2019s List of the Best Recreational Pontoon Boats for Sale. The mounting height of an outboard motor can impact the speed and handling characteristics of the boat. endobj Mounting the outboard motor in accordance with the industry standards is important. Any questions? It is extremely important that the boater understands the significance of the transoms height. It does not store any personal data. bracket. addyd53b59933f6c3f2e8b59f1b4a6d41fa5 = addyd53b59933f6c3f2e8b59f1b4a6d41fa5 + 'vanssports' + '.' + 'com'; 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. Now that you have a better understanding of boat transom heights its time to take out the ruler and get the perfect measurements. With it comes a lot of responsibility and new things to learn including boat maintenance and boat basics. As summer approaches there will be more boaters taking to the water. We also use third-party cookies that help us analyze and understand how you use this website. It was a 23-foot Crestliner Grand Cayman pontoon boat. maxTerm: 36, var path = 'hr' + 'ef' + '='; A: The short answer is Yes. <>/ExtGState<>/XObject<>/ProcSet[/PDF/Text/ImageB/ImageC/ImageI] >>/MediaBox[ 0 0 595.2 841.8] /Contents 4 0 R/Group<>/Tabs/S/StructParents 0>> Other uncategorized cookies are those that are being analyzed and have not been classified into a category as yet. If your boat is newer and the manufacturer is still in business, you might also want to try to give them a call. Beyond motorboats designed for large outboards, you will see outboards hanging on the sterns of everything from small canoes to large cruising sailboats. Other factors to consider when determining the mounting height of an outboard are related to performance. clearInterval(interval); For most boaters this is a no brainer, but for the novice or inexperienced boater it may be a tougher question. In extremes, the engine can have overheating problems if the boat is raised to a point where the water inlets for the cooling system are out of the water. document.getElementById('cloakd53b59933f6c3f2e8b59f1b4a6d41fa5').innerHTML = ''; var addy_textd53b59933f6c3f2e8b59f1b4a6d41fa5 = 'info' + '@' + 'vanssports' + '.' + 'com';document.getElementById('cloakd53b59933f6c3f2e8b59f1b4a6d41fa5').innerHTML += ''+addy_textd53b59933f6c3f2e8b59f1b4a6d41fa5+'<\/a>'; It doesnt matter if you have a fiberglass boat, bay boat, big or small boat. It also cuts into speed and fuel efficiency. The first step is to determine the height of your boat's transom. Or measure from the main engine prop up to the water line? the aluminum plate on top of the transom), to the bottom of the motor 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. (127 mm). What the relationship to the pontoons is, I couldn't say. Boaters who consider going with a higher mount can see increased speeds. |. This placement is not only recommended but it will give you the best performance compared to something that is too long or too short. }, 100); A1: Broadly speaking, the outboard motor shaft length for pontoon boat, bass boat, or other larger boats should be long shaft. August 9/08). parallel with the straight edge. This is measured by the propeller shaft being parallel to the vessels bottom. I would ask you to go back and measure the transom of your boat. All boats are different, and the motor manufacturers produce a variety of standard lengths. 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. enableMoreInfoLink: true, Well, raising the outboard motor can be an easy task for you. Analytical cookies are used to understand how visitors interact with the website. Mounting the motor lower on the boat transom can create excessive spray, increase case drag, reduce underwater clearance, and negatively impact faster boats. Not to measure boat speed, but to gauge the mounting height of the outboard motor on the boat transom. One of the great things about an outboard motor is how versatile it is. No one wants to have issues with a new transom or boat repairs. This will keep the prop in the water when the boat pitches in waves, or hobby-horses. Cutting the transom down is the only legal method to utilize a short shaft engine on a tall transom. With it comes a lot of responsibility and new things to learn includingboat maintenanceand boat basics. 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. If you said something smaller than that, thats where it can get tricky. brackets. The same is true for the newest, high-powered offshore fishing boats, where triple or quadruple motor setups are becoming more and more common. Doing this can have adverse effects. Typical motor lengths include the following. The average transom angle is around 14 degrees. 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. var interval = setInterval(function () { The engine must be linked to the transom at the proper height for a propeller to best meet specific boating demands. In addition, motor totes will not harm the finish of the lower unit. 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. Most transom savers can support up to a 150HP motor, which is sufficient for most regular boats. The brackets can add 1 inch to the overall mounting height of the outboard. With some boats I have a pretty good idea as to what length motor should be hung on them. If you have a question or need additional information,contact ustoday. 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. All rights reserved. Industry standards dictate that for short shaft engines the transom height should be 15. Workboats, sailboats, and displacement-hulled boats fall into this category. This is somewhat similar to #2, in that you are again measuring with a 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. maxAmount: 6500.0, x\[D~OUCO6[j](l%ay <8cylY{.L2s#]~U6A|Wj]-oo|mubqY6wbY_|!>Z8(RB:RHeTzOGO_=~t\ 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 cookie is used to store the user consent for the cookies in the category "Other. It will ensure that the outboards trim will be effective, and it will save you gas too. minAmount: 300.0, You dont have to be a mathematician to determine the correct boat transomangle. 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. As a dealer I don't really like hearing this because there is a chance it could go either way and you have to get it right. 2 0 obj 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. It is extremely important that the boater understands the significance of the transom's height. 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. 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. Should I take the raft onto the water and measure the exact distance from the top of the transom to the water line? A big NO. What is the Virtual Sundance Film Festival? Buying a boat can be an exciting purchase. Brackets are also handy for boats that do not have flat transoms, like canoe-stern sailboats or fan-tailed motor vessels. This illustration depicts four different outboard mounting height options (courtesy Mercury Marine). On the downside, a higher mount can interfere with the boaters steering capabilities. 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? With a jack plate, you can mount it exactly where you want it. Your goal is to measure how the outboard will sit, so start from the clamping plate and follow the centerline of the hull. The amount of degrees the transom leans back from vertical is known as the transom angle. Now that you have a better understanding of boat transom heights its time to take out the ruler and get the perfect measurements. 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. Your email address will not be published. straight edge from the center of the pad, but this time you're measuring If you go too short your more than likely going to cavitate and loose power. What are Apple Podcasts Subscriptions and Channels? You can use a longer shaft than recommended and your boat will work fine. How do you measure a transom on an outboard motor? A long shaft engine requires a height of 20 and extra-long shaft engines will need a transom height of 25. 4 0 obj Where Onboard a Boat is the Transom Located and More About Transom Heights A propeller operates based on the height of the transom. These two measurements will give you the length of the shaft you need. This cookie is set by GDPR Cookie Consent plugin. Amazon has plate extensions to allow adjustments without buying a new motor: T-H Marine Jack Plate Extension. The pressure behind your hand dropped as you slid your hand back and forth through the water. Long shafts are 20-inches long. Step 2 requires the propeller's radius (check the user manual and then the technical drawing). You need JavaScript enabled to view it. Take a long straight edge, (long carpenter's level or long The center is the point where your outboard motor is (ideally) located. actually have the propshaft above the pad.). 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. The faster your boat, the more critical it is to get the sizing just right. } Safely but briskly accelerate. The standard installation of an outboard has the top of the transom of the boat at the same level as the bottom of the motor portion of the outboard. Engine Oil Type Genuine or Recommended 2str Engine Oil. So how to measure outboard shaft length? Tilt your motor until the bullet of the gearcase is This alone can outweigh the negatives when deciding to adjust the mount upwards. Attention: Remember to measure the outboard shaft length straight up and down instead of measuring along the transom. Use the mounting bracket on the motor to know where it will sit on the boat. 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. These cookies help provide information on metrics the number of visitors, bounce rate, traffic source, etc. 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. Extra-extra long shafts are 30-inches long. endobj On this type of boat, if you are in doubt, default to the longer-shafted outboard. (Putting a stream These are vertically aligned so the boater can make adjustments. Some boats are equipped with transom-hung outboards while others have a bracket. If the height of the boat transom is off it can cause major issues. You will also risk hitting bottom or submerge objects more frequently such as rocks or logs. Some fishing boats can handle the motor being underwater. The form of a boats transom varies depending on the manufacturer and model. Small portable outboards ranging from 2 to 20 horsepower are usually sold only in short or long shaft versions. A reversetransom that sits too high can impact the propellers of the motor and motor bracket. Top 10 Choices for Boaters, Mercury Introduces 600HP V12 Verado Outboard Engine, The Outboard Expert: Tohatsu Propane Outboard Engine. See diagram below. A retired ship captain, Charpentier holds a doctorate in applied ocean science and engineering. s = d.createElement("link"); Follow Westshore Marine & Leisure on Twitter! They keep water out of your prop and increase water pressure in the system. You must be still in the blue about that matter. *The Factors indicates the adjustment affected by on your boat type, the outboard working environment, and the transom distance as discussed above. Industry standards dictate that for short shaft engines the transom height should be 15. Take your time and understand your boat and your entire transom. In the past, though, it housed the officers and captain of 17th, 18th and 19th century sailing ships. Re: Dinghy with a long shaft motor? 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. Other boats that need long shafts are. This cookie is set by GDPR Cookie Consent plugin. Since the length of the shaft of your outboard is associated with the size boat, smaller engines will generally have shorter shafts. 5/rC,aQhsK@Q. However, you will need an understanding of how the degrees will alter the boats usability. Boat hulls are designed in three basic types that range from slow displacement and semi-displacement hulls to the fastest planing hulls. 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. A: Any boat that has a 21 to 27 inch aft transom will need an extra long shaft outboard. They operate as a planing surface, allowing your boat to climb to the top more quickly. Beginning boaters should be aware of the boats measurements. from the transom. Lubrication System Engine Oil Mixed Gasoline. You reply, "Im not sure, I think its a long". If you went too long it would still work but it may lack in performance. "brackets". This, however, is not recommended for the beginning boater. This is probably the worst case scenario out of the two. Smaller inflatables and dinghies needshort shaft motors, whilst bigger boats require long or, in some circumstances, extreme long shaft versions. What's the best height for my boat motor? This cookie is set by GDPR Cookie Consent plugin. Each one has a totally different effect on the boats performance. } Expectedly, when the transom angle is zero, it means it is flat. Simply start with the engine in idle, followed by, If you decide to make some custom adjustments we have the. There is a simple test to see if your outboard motor is set at the best height. trimming the motor out by one-half to full trim. Then adjust the motor in a higher hole with a flat head screwdriver. To make the yard stick long enough to measure the length of all the clubs, tape the ruler to the top. When you measure the width of the stern, mark the center with a grease pencil. Chances are the boat was designed with a specific size of outboard in mind. As you can see, the measurement is about 2 1/2".
how to measure transom height for outboard motor
how to measure transom height for outboard motor
