d.addEventListener("DOMContentLoaded", function (e) { This measurement would be the inches of mpeInit(); Oftentimes you will want to adjust the outboard shaft length in order to improve the boat performance such as speed. Add the two measurements and you get 6 1/2". Each one has a totally different effect on the boats performance. There are 2 steps to help get a relatively accurate figure. If it measures anywhere from 17" to around 22", then your going to want to go with a long shaft motor. In lower mounting, the engine is set lower than the recommended standard. Typical motor lengths include the following. If you are running a slower boat, the exact location of the ventilation plate is less important. Will Charpentier is a writer who specializes in boating and maritime subjects. As summer approaches there will be more boaters taking to the water. (Putting a not sure that it's still used. The boat transom height is measured from the lowest point on the keel along the center line to the spot where the outboard motor's mounting holes bracket rests. Simply start with the engine in idle, followed by trimming the motor out by one-half to full trim. disregard the "hooks" at the front of the All boats are different, and the motor manufacturers produce a variety of standard lengths. You reply, "Im not sure, I think its a long". gtag('js', new Date()); 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. 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. Is my outboard long or short shaft? The transom is the "back wall" of your boat, the most rearward part of your hull. The boater must also consider if the boat transom support is designed to bear the weight of a higher mount. With the long side (22 1/2), place a carpenters square ) in opposition to the keel. #1: Height Take your time and understand your boat and your entire transom. var prefix = 'ma' + 'il' + 'to'; Make sure that you are measuring straight up, at a 90 degree angle to 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. 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 transom's height. Pretty easy to figure out but like I said its crucial to pairing a motor with a boat. Generally, the anti-ventilation plate on most engines is aligned with the bottom of the vessel. Beginning boaters should be aware of the boats measurements. These cookies will be stored in your browser only with your consent. You can use a longer shaft than recommended and your boat will work fine. Since the length of the shaft of your outboard is associated with the size boat, smaller engines will generally have shorter shafts. Boat transomangles play a pivotal role in the flexibility of the boats trimming abilities. See diagram below. Outboard shaft length plays a crucial role in the performance of your boat. Beginning boaters should be aware of the boats measurements. A deep Vee hull will result in a different measurement than a flatter . 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. up to the bottom of the motor brackets, (as in #1). Like Westshore Marine & Leisure on Facebook! It also cuts into speed and fuel efficiency. 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. Many boat transoms are modified to use a different length of outboard by using a bracket. This could also affect your travelling capabilities on the boat trailer. The center is the point where your outboard motor is (ideally) located. Also, how do you determine the length of an outboard transom? The boater must also consider if the boat transomsupport is designed to bear the weight of a higher mount. Another important measurement is the transom angle. If you have a question or need additional information,contact ustoday. 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. displayPrimeOffers: true, If you go too short your more than likely going to cavitate and loose power. Whether you already own a boat or looking for your first watercraft we are here to service your needs. There are a series of four to six holes at the top of the bracket, and the lower bolts actually fit into slots. Anything bigger than that your obviously going to need an extra long shaft. steel ruler, etc. If you said you have a pontoon or a larger style boat such as a bass boat or speed boat, I would be pretty confident in saying it needs a long shaft. Keith Allen, a 1979 graduate of Valley City State College, has worked at a variety of jobs including computer operator, medical clinic manager, radio talk show host and potato sorter. document.getElementById('cloakd53b59933f6c3f2e8b59f1b4a6d41fa5').innerHTML = ''; This is a measurement that has been used for BassCats, I'm When the right length motor is hung on the transom of a boat, the cavitation plate (the large plate that extends out over the propeller) should be even with the very bottom of the boat. As a yacht designer and boater, I prefer longer shafts. (function (d) { Amazon has plate extensions to allow adjustments without buying a new motor: T-H Marine Jack Plate Extension. This cookie is set by GDPR Cookie Consent plugin. would be more accurate.) 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. MarinePartsMan.com also says that V6 bass-boat engines have a 20-inch shaft. C Cheaptoon Cadet Joined Aug 4, 2010 Messages 28 Aug 24, 2010 #4 Re: Motor height on pontoon? Always weigh the risks of making adjustments. 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. Place the bracket on the transom to the left of the main outboard or rudder. What Kind of Fuel Does Your Marine Engine Need? Now that you have a better understanding of boat transom heights its time to take out the ruler and get the perfect measurements. I also love helping others, which is why I created this website. An outboard motor can drive just about any sort of boat with proper mounting. On this type of boat, if you are in doubt, default to the longer-shafted outboard. 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. var addyd53b59933f6c3f2e8b59f1b4a6d41fa5 = 'info' + '@'; Mounting the outboard motor in accordance with the industry standards is important. The Effects of Standard, Lower and Higher Mounting. These are vertically aligned so the boater can make adjustments. You will also risk hitting bottom or submerge objects more frequently such as rocks or logs. Be sure to measure carefully and research thoroughly before diving in. The performance of these boats depends on quite a lot of factors, but getting the outboard length just right is an essential first step. By clicking Accept, you consent to the use of ALL the cookies. Extra-long shafts are 25-inches long. This website uses cookies to improve your experience while you navigate through the website. 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. primeApr: 12.99, This will keep the prop in the water when the boat pitches in waves, or hobby-horses. Height Measurement: Recommended Shaft Length: 14" - 17.25" 15" Shaft (Short) 17.25" - 19.5" Varies by application 19.5" - 22.5" 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}'); 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. Its where the outboard motor is attached, and its also where some boat owners put the boats name. Displacement hulled vessels like sailboats and workboats can benefit from a little more space between the hull and cavitation plate, but not much. 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. Copyright 2017 Dealer Spike All Rights Reserved. It can also improve the experience of driving a faster boat. 12 Small Fishing Boat Accessories to Buy Today. s.setAttribute("href", "https://cdn.paytomorrow.com/css/pt-mpe.min.css"); As a result, the issue is whether my boat need a short shaft or long shaft motor. <>/ExtGState<>/XObject<>/ProcSet[/PDF/Text/ImageB/ImageC/ImageI] >>/MediaBox[ 0 0 595.2 841.8] /Contents 4 0 R/Group<>/Tabs/S/StructParents 0>> If your boat is newer and the manufacturer is still in business, you might also want to try to give them a call. If you have a question or need additional information. h[0].appendChild(s); Although the longer outboard shaft length can lead to lower speed and more drag, the boat can push a heavier load. But in many cases, its a little more complicated than that alone. 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. If the propeller fails to ventilate, the motor is mounted to low. Using your existing control box and gauges will save you quite a bit of money in the end. Follow Westshore Marine & Leisure on Wordpress! Basically, there are three main ways to measure motor Whats the best height for my boat motor? var xmlHttp = new XMLHttpRequest(); This, however, is not recommended for the beginning boater. Mounting the outboard motor in accordance with the industry standards is important. Other boats that need short shafts are: A: If you have a small boat with a 18 to 21 inch aft transom, youll most likely need a long shaft outboard. Problems with getting the ventilation plate too low include slower hole-shot and lower top-end speeds. function loadScript(script) { Of course, its always best to go with standard practices when choosing thebest boat engine. They operate as a planing surface, allowing your boat to climb to the top more quickly. 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. Higher mounting decisions should be left to the professionals. Remanufactured 4 Cylinder 4-Stroke Cylinder Heads, Remanufactured 6 Cylinder 4-Stroke Cylinder Heads, Trim Relays, Trim Solenoids & Sending Units, Remanufactured V6 & V8 4-Stroke Cylinder Heads, Volvo Cobra SX Bearings and Bearing Carriers, Volvo Cobra SX Driveshaft, U-Joints & Parts, Volvo Cobra SX Transom Assembly & Bellows. Measure from the top of the straight edge to the center of the front resting on the transom if you had the motor all the way down on the boat In the photo above, we've measured from the motor bracket to the top of What is Transom Height? It is very versatile as it generally . Boats that use longer outboard shafts include: endobj If you are running a twin-engine setup, then measure the same distance from each clamping plate to the bottom of the hull. In step 3, add another 10 cm (4") to the previous calculation in order to develop the ideal shaft length. Remember, if you use a longer outboard shaft than you need you will be increasing your draft. But opting out of some of these cookies may affect your browsing experience. I mean, who wants to purchase something as expensive as an outboard to only realize you bought the wrong one. However, there may be times when a boater strays away from these recommendations. Smaller boats may use adjustable jack plates that can be changed to fit any outboard. Step 2 requires the propeller's radius (check the user manual and then the technical drawing). All rights reserved. priceSelector: ".price--withoutTax, span.price.price--withTax", s.setAttribute("src", script); You also have the option to opt-out of these cookies. parallel with the straight edge. It is extremely important that the boater understands the significance of the transoms height. He is also a certified marine technician and the author of a popular text on writing local history. If it measures between 17 and 22, you'll want to go with a long shaft motor. I would ask you to go back and measure the transom of your boat. Doing so, will put the propeller right below the boat. This distance is very important to the performance of you boat. 3 0 obj Bass boats, ski boats, or center cockpit vessels will want to double-check their measurements to get it just right. Increased RPM and additional horsepower feed the need for speed. bracket. debugMode: false, Any owner seeking the last bit of speed from an outboard-powered boat should grab a yard stick. Then finally test your outboard, if the mount is perfect. I believe 20 to 21 inches is the optimum length for a lengthy shaft. Boaters who consider going with a higher mount can see increased speeds. You must be still in the blue about that matter. Having the cavitation plate too low will cause excess drag and reduced performance at high speeds. Many single-engine boats mount a smaller auxiliary motor for emergency use. Attention: Remember to measure the outboard shaft length straight up and down instead of measuring along the transom. straight edge from the center of the pad, but this time you're measuring Other factors to consider when determining the mounting height of an outboard are related to performance. Over time, Boating Hub has grown into a resource for boating enthusiasts around world. want to measure from the transom to the flat part of this bracket, The outboard comes with mounting holes and brackets. There are also specialty motor shaft lengths. Most of the time, adding a hydrofoil to an outboard improves performance. Increased RPM and additional horsepower feed the need for speed. How Transom Height Is Measured 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. Doing this can have adverse effects. Measure the area of the transom directly where the engine will be mounted. jackplate to a point level with the top of the transom. Plus, a low transom cut is an invitation for the water to flood the boat. Mounting the outboard a little bit lower than the standard point could avoid the possible ventilation and slip on acceleration. Outboard Motor Shaft Length: How do I measure? Check out the full chart of the Mercury outboard model code and its features. 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. So from there, I will try to help out by asking questions about your boat such as what type it is and the length. Whether you already own a boat or looking for your first watercraft we are here to service your needs. 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. 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. Save my name, email, and website in this browser for the next time I comment. Mounting the motor lower on the boat transomcan createexcessive spray, increase case drag, reduce underwater clearance, and negatively impact faster boats. 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). 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. When you measure the width of the stern, mark the center with a grease pencil. The transom in a boat today is a place to hang your outboard motor. With some boats I have a pretty good idea as to what length motor should be hung on them. The motor is what powers the boat so the two go hand-in-hand. Safely but briskly accelerate. Outboards designed for saltwater applications usually have longer shafts. Your email address will not be published. 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. No one wants to have issues with a new transom or boat repairs. So how to determine the outboard shaft length? ), Al Shields }) } }); })(document); Check out some hot FAQs to help you get the proper outboard shaft lengths. This restriction includes most fishing boats and longer sailboats. The prop will be in cleaner, harder water as it advances farther aft, making it more efficient. The transom is the rear wall of the boat where the outboard engine is mounted in the middle. maxTerm: 36, This is measured by the propeller shaft being parallel to the vessels bottom. We also use third-party cookies that help us analyze and understand how you use this website. It also includes attaching the right engine. This measurement was approximately 4". What is the Virtual Sundance Film Festival? These cookies track visitors across websites and collect information to provide customized ads. Smaller inflatables and dinghies needshort shaft motors, whilst bigger boats require long or, in some circumstances, extreme long shaft versions. However, you will need an understanding of how the degrees will alter the boats usability. Then adjust the motor in a higher hole with a flat head screwdriver. For example, you can have the Mercury outboard shaft length by model code. Having the cavitation plate a bit lower than the transom is preferable to having it too high. It doesnt matter if you have a fiberglass boat, bay boat, big or small boat. Place the clubs bottom on the ground as though it were going to be used to strike a golf ball. You need JavaScript enabled to view it. Engine Oil Type Genuine or Recommended 2str Engine Oil. The cavitation plate is the horizontal surface of the lower unit immediately above the propeller. 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. var path = 'hr' + 'ef' + '='; 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. Since the ventilation plate & foil are burried under water it is obviously too low. from the transom. Should I take the raft onto the water and measure the exact distance from the top of the transom to the water line? It doesnt matter if you have a fiberglass boat, bay boat, big or small boat. Follow Westshore Marine & Leisure on Twitter! xmlHttp.setRequestHeader('Content-Type', 'application/json'); The engine must be linked to the transom at the proper height for a propeller to best meet specific boating demands. former editor at Boating Magazine and contributor to many national publications Then open up the clamp bucket. So how to measure outboard shaft length? Boat transom angles play a pivotal role in the flexibility of the boats trimming abilities. Attention: Remember to measure the outboard shaft length straight up and down instead of measuring along the transom. bassboat can be a bit confusing at times; hopefully this will help sort Here we will guide you in how to get the right boat transom height. The lowest point will likely be directly under your drain plug if youve got one. For vee-shaped hulls, the lowest spot of the hull will come to point, while on flat-bottomed boats it will be more or less level. Keep these numbers in mind if you ever have a need for a new outboard motor for your boat. manufacturer will recommend the outboard height according to the bracket shape and length. Small portable outboards ranging from 2 to 20 horsepower are usually sold only in short or long shaft versions.