Pad to bottom of 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. 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. This is handy if youre shopping for second-hand outboards or looking to sell the one that came with your boat. Other boats that need long shafts are. Required fields are marked *. 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. Since the length of the shaft of your outboard is associated with the size boat, smaller engines will generally have shorter shafts. The cookies is used to store the user consent for the cookies in the category "Necessary". Youll also want to pay attention when youre in shallow water because your prop will be lower than normal. In lower mounting, the engine is set lower than the recommended standard. since 1986. var interval = setInterval(function () { will be to the flat part; if you measure to the bottom of the brackets For really big boats, the biggest and baddest six- or eight-cylinder outboards can have extra-extra long shafts up to 30 inches. It moves an outboard up and down to optimize performance and enable a boat to venture into shallower water than it might otherwise. disregard the downward pointing "hooks" at the front of the Among them will be first-timers or those who have recently purchased their boats. As you can see, the measurement is about 2 1/2". 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. You will also risk hitting bottom or submerge objects more frequently such as rocks or logs. With a jack plate, you can mount it exactly where you want it. Also, the boat will be more likely to hit bottom or submerge objects such as rocks or logs. These cookies ensure basic functionalities and security features of the website, anonymously. It was a 23-foot Crestliner Grand Cayman pontoon boat. Should I take the raft onto the water and measure the exact distance from the top of the transom to the water line? This measurement would be the inches of Say the 20 shaft is a long shaft length for gas engines, but it is a short shaft length for electric outboard motors. | Sitemap, The Marine Parts Warehouse Outboard Museum, OBR Powerhead / Shortblock Warranty Claim Form, Remanufactured vs. Ten years ago I bought my first 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. h[0].appendChild(s); 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. The clamp bracket is designed so that the engine's mounting height on the transom can be adjusted higher than standard. Whether you already own a boat or looking for your first watercraft we are here to service your needs. Then test the boat and adjust the height, if necessary . It is possible that the motor could hang low while transporting on the boat trailer causing future boat repairs. As with anything, there are exceptions to the rule. Its where the outboard motor is attached, and its also where some boat owners put the boats name. A deep Vee hull will result in a different measurement than a flatter . Mounting the outboard motor in accordance with the industry standards is important. 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. function gtag(){dataLayer.push(arguments);} Industry standards dictate that for short shaft engines the transom height should be 15. 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. The cookie is set by GDPR cookie consent to record the user consent for the cookies in the category "Functional". The transom angle is the vertical incline of the transom and is measured in degrees. However, there may be times when a boater strays away from these recommendations. measuring; you may have to "extend" the flat part of the Gear case sits just below or at the hull depth due to the deep v. Depending on the manufacturer, size names might change. Rebuilt - What You Need to Know, Lower Unit and Sterndrive Break-In Instructions. Take a long straight edge, (long carpenter's level or long Ill also explain the difference between short and long shafts and how they vary by type of boat. Shaft lengths are available in increments of 5. Why wont Touch ID be under the screen in the iPhone 15 and iPhone 16? Save my name, email, and website in this browser for the next time I comment. To measure the transom height, measure from the center on for transom (rear of the boat). Again, make sure that you are measuring to the flat part of the brackets; (Putting a <> All rights reserved. Boat Transom Heights The Beginners Guide, Buying a boat can be an exciting purchase. You can order an outboard in lengths ranging from 15 inches to 30 inches, depending on its power output and possible uses. There are 2 steps to help get a relatively accurate figure. It also cuts into speed and fuel efficiency. This will keep the prop in the water when the boat pitches in waves, or hobby-horses. The standard shaft length for most outboard engines less than 125 horsepower is 20 inches. #2. Chances are the boat was designed with a specific size of outboard in mind. Now that you have a better understanding of boat transom heights its time to take out the ruler and get the perfect measurements. 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? 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. Check out the Westshore Marine & Leisure google plus page! Some fishing boats can handle the motor being underwater. Generally, the anti-ventilation plate on most engines is aligned with the bottom of the vessel. from the transom. Small motors built for sailboats might come in a unique configuration with an extremely long shaft since these are mounted higher off the water. trimming the motor out by one-half to full trim. However, the shaft length for smaller boats could be long or short depending on its style, speed requirement, etc. 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. to where the brackets were actually resting on the transom. 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. These are vertically aligned so the boater can make adjustments. Raising an outboard higher on the transom can reduce drag and raise top speed. The how to measure the shaft length of an outboard motor is a question that many people have asked. Also, how do you determine the length of an outboard transom? How high exactly do you have to raise the transom?-. Safely but briskly accelerate. (1) Multiply the overall length of your boat (in feet) by it's widest beam at the stern (excluding any Fins and or Shear) (2) Locate that value on the left hand vertical column of the chart below. Cutting the transom down is the only legal method to utilize a short shaft engine on a tall transom. The propellers will also have trouble reaching the water. 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. Before we get started lets see what a boat transom is and what it does. When fighting waves from the stern, a 20-inch transom is considerably safer. Check out some hot FAQs to help you get the proper outboard shaft lengths. However, the motor should not be raised more than 5 inches above the standard position. Or it can have an angle degree as high as 30. This will ensure the best performance. mpeInit(); This is a measurement that has been used for BassCats, I'm This is the dimension you'll need to know when deciding between a short shaft, long shaft or extra long shaft for your outboard motor. If you said something smaller than that, thats where it can get tricky. s.setAttribute("type", "text/javascript"); In step 3, add another 10 cm (4") to the previous calculation in order to develop the ideal shaft length. This, however, is not recommended for the beginning boater. displayPrimeOffers: true, Extra-long shafts are 25-inches long. 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. Keep these numbers in mind if you ever have a need for a new outboard motor for your boat. The cavitation plate is the horizontal surface of the lower unit immediately above the propeller. %PDF-1.7 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. In lower mounting, the engine is set lower than the recommended standard. Workboats, sailboats, and displacement-hulled boats fall into this category. var h = d.getElementsByTagName("head"), <>/ExtGState<>/XObject<>/ProcSet[/PDF/Text/ImageB/ImageC/ImageI] >>/MediaBox[ 0 0 595.2 841.8] /Contents 4 0 R/Group<>/Tabs/S/StructParents 0>> Boat transom angles play a pivotal role in the flexibility of the boats trimming abilities. His works have appeared in regional newspapers in North Dakota and in "North Dakota Horizons" and "Cowboys and Indians" magazines. Determining Your Boat Transom Angle The transom angle - commonly measured in degrees - is the transom's vertical inclination. 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. Beginning boaters should be aware of the boats measurements. Outboard motors can be fitted to a variety of boats, so manufacturers have standardized their engines to go on virtually anything. In the second photo, we've measure down from the top of the Detwiler Its important to note that manufacturers call their models different things. Tightening Torque for Engine. Among them will be first-timers or those who have recently purchased their boats. I would ask you to go back and measure the transom of your boat. I hope this helps someone out in their search for a new or newer outboard this season. 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. Tilt your motor until the bullet of the gearcase is Triton. former editor at Boating Magazine and contributor to many national publications 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. Keep these numbers in mind if you ever have a need for a new outboard motor for your boat. When mounting the engine, you want the cavitation plate to be 1 above the boat bottom for every 12 away from the transom. Each one has a totally different effect on the boats performance. ), and place it on the bottom of the pad in the center. Add yours in the comment and Ill get back to you asap. What types of boat need an extra long shaft? 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. You need JavaScript enabled to view it. Re: Dinghy with a long shaft motor? Smaller 12-14 foot boats can require either a short or long shaft outboard depending on the style of the boat and the brand. When trimming your motor, they provide you a greater bow response. In the photo above, we've measured from the motor bracket to the top of 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. No one wants to have issues with a new transom or boat repairs. Look at the part of your motor that would be Cavitation plates are used on the bottom components of boats to help them operate better. of the motor off the transom Remember, if you use a longer outboard shaft than you need you will be increasing your draft. To break it down a bit more for you: Short shafts are 15-inches long. Learn More About Your Boats Systems By Joining The Born Again Boating Academy! 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 would not be a good thing. The outboard comes with mounting holes and brackets. (In the case of the faster 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. This was the height of my 225 Yamaha on my TR21 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. Save my name, email, and website in this browser for the next time I comment. In the case of a larger offshore boat, it may be to the top of a cutout on the . bracket forward with a straight edge to where you can then measure up Actual shaft length is 21.5" on those. All you need to do is measure how much to rise. So how to measure outboard shaft length? What the relationship to the pontoons is, I couldn't say. Before we start measuring the outboard shaft length, lets get it clear about whats referring to when we talk about the outboard shaft length. 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. 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. maxAmount: 6500.0, The faster your boat, the more critical it is to get the sizing just right. The cookie is used to store the user consent for the cookies in the category "Other. Of course, its always best to go with standard practices when choosing thebest boat engine. Extra-extra long shafts are 30-inches long. Analytical cookies are used to understand how visitors interact with the website. On this type of boat, if you are in doubt, default to the longer-shafted outboard. bracket. C Cheaptoon Cadet Joined Aug 4, 2010 Messages 28 Aug 24, 2010 #4 Re: Motor height on pontoon? Now that you have a better understanding of boat transom heights its time to take out the ruler and get the perfect measurements. Pretty easy to figure out but like I said its crucial to pairing a motor with a boat. relation to pad It doesnt matter if you have a fiberglass boat, bay boat, big or small boat. The clamp bracket on the latest Mercury Four-Stoke-model outboards has five mounting bolt holes spaced .75 inches apart. Higher mounting decisions should be left to the professionals. Measure from the top of the straight edge to the center of the front }, 100); The same is true for the newest, high-powered offshore fishing boats, where triple or quadruple motor setups are becoming more and more common. Advertisement cookies are used to provide visitors with relevant ads and marketing campaigns. The brackets can add 1 inch to the overall mounting height of the outboard. Oftentimes you will want to adjust the outboard shaft length in order to improve the boat performance such as speed. 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. This is simply a measurement taken from the top of the transom (top of steel ruler, etc. })(); If youd like to see this in video format, skip to 0:44 in the below YouTube Video: Is it OK to put a long shaft outboard on a boat thats rated for a short shaft? This provides seaworthiness and offers maximum protection from large seas. However, there may be times when a boater strays away from these recommendations. Place the rulers end on the ground behind the club and let the club to rest on top of it. I run a 9.9 Mercury Bigfoot 20" shaft off the swim platform of my 89 Trophy 2160. The mounting height of an outboard motor can impact the speed and handling characteristics of the boat. This alone can outweigh the negatives when deciding to adjust the mount upwards. There are a series of four to six holes at the top of the bracket, and the lower bolts actually fit into slots. With it comes a lot of responsibility and new things to learn including boat maintenance and boat basics. Where Onboard a Boat is the Transom Located and More About Transom Heights A propeller operates based on the height of the transom. Owners of bass boats, RIBs, or offshore fishing boats need to get this right. In addition, motor totes will not harm the finish of the lower unit. With some boats I have a pretty good idea as to what length motor should be hung on them. The height of the boat transom dictates the size of the outboard motor. Youll need a short shaft outboard if its 15 or less than an inch shorter. Then finally test your outboard, if the mount is perfect. Copyright 1999-2023 Boats Group. 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. To do so, you will want to measure at the exact center of the transom from the very top to the very bottom.
how to measure transom height for outboard motor
01. jul