function loadScript(script) { Usually speaking, the farther the outboard is set off the transom, the higher the propeller should be in the water (or the higher the outboard can be mounted). 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. This could also affect your travelling capabilities on the boat trailer. Repowering your boat is one of the most expensive upgrades you can make. Recommended Engine Oil 2-Stroke Outboard Motor Oil. }, 100); 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. Small motors built for sailboats might come in a unique configuration with an extremely long shaft since these are mounted higher off the water. As with anything, there are exceptions to the rule.
Outboard Motor Shaft Length & HP to Boat Calculating Knowing how this can affect the overall operation of the boat is a factor to be considered. <>/Metadata 127 0 R/ViewerPreferences 128 0 R>>
s.setAttribute("src", script); 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. There are 2 steps to help get a relatively accurate figure. Also, the boat will be more likely to hit bottom or submerge objects such as rocks or logs. Smaller 12-14 foot boats can require either a short or long shaft outboard depending on the style of the boat and the brand. Your at your local outboard dealer shopping for a new motor and the salesman hits you with the question, "short or long shaft?". All rights reserved. Generally, the anti-ventilation plate on most engines is aligned with the bottom of the vessel. C Cheaptoon Cadet Joined Aug 4, 2010 Messages 28 Aug 24, 2010 #4 Re: Motor height on pontoon? 1 0 obj
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. Check out the Westshore Marine & Leisure google plus page! Make sure that you are measuring straight up, at a 90 degree angle to
https://www.bornagainboating.com/Get Your Born Again Boating Clothing! It also cuts into speed and fuel efficiency. Raising an outboard higher on the transom can reduce drag and raise top speed. 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. Youll need a short shaft outboard if its 15 or less than an inch shorter. A big NO. minAmount: 300.0, Engine Oil Mixing Ratio Fuel 50: Engine Oil 1. The engine must be linked to the transom at the proper height for a propeller to best meet specific boating demands. Doing this can have adverse effects.
They operate as a planing surface, allowing your boat to climb to the top more quickly. boats.com is part of the Boats Group Network. The height of the boat transom dictates the size of the outboard motor.
The Best Way to Measure Prop to Pad | How to measure Outboard Motor Height The transom angle is the vertical incline of the transom and is measured in degrees. enableMoreInfoLink: true, 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 mounting height of an outboard motor can impact the speed and handling characteristics of the boat. 2 0 obj
Next, measure from your centerline to where the outboard will be mounted on each side. Place the clubs bottom on the ground as though it were going to be used to strike a golf ball. The cookie is used to store the user consent for the cookies in the category "Analytics". gtag('js', new Date()); For really big boats, the biggest and baddest six- or eight-cylinder outboards can have extra-extra long shafts up to 30 inches. })(); For boats equipped with a bracket, calculate the same measurement but based on the bracket and not the transom. of the motor off the transom
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. I hope this helps someone out in their search for a new or newer outboard this season. Another important measurement is the transom angle. function gtag(){dataLayer.push(arguments);} Industry transom height standards have been evolved during the last 30 years: 15 for short shaft engines, 20 for long shaft engines, and 25 for extra-long shaft engines. Required fields are marked *. the propshaft below or above the pad. There are a series of four to six holes at the top of the bracket, and the lower bolts actually fit into slots. Here we look at the effects of standard, lower and higher mounting. Tilt your motor until the bullet of the gearcase is
So how to determine the outboard shaft length? To sum up, there is a simple calculator of the shaft length for outboard motors: Outboard Shaft Length = Transom Height +/- Factors. When fighting waves from the stern, a 20-inch transom is considerably safer. x\[D~OUCO6[j](l%ay <8cylY{.L2s#]~U6A|Wj]-oo|mubqY6wbY_|!>Z8(RB:RHeTzOGO_=~t\ 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. The cookie is set by GDPR cookie consent to record the user consent for the cookies in the category "Functional". This cookie is set by GDPR Cookie Consent plugin. Then finally test your outboard, if the mount is perfect. :$I>M W$h"%U_yzIb?]NHg_G|r@nX eTf."SQ With some boats I have a pretty good idea as to what length motor should be hung on them.
What Is the Transom of a Boat? EXPLAINED - My Cruiser Life Long Shaft vs. Short Shaft Outboard (What Are the Differences?) relation to pad
Brackets are also handy for boats that do not have flat transoms, like canoe-stern sailboats or fan-tailed motor vessels. 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 email address is being protected from spambots. The outboard comes with mounting holes and brackets. Beyond motorboats designed for large outboards, you will see outboards hanging on the sterns of everything from small canoes to large cruising sailboats. Many single-engine boats mount a smaller auxiliary motor for emergency use. A transom saver, which can change the spacing between the lower unit and the trailer, negates some of the support. The propellers will also have trouble reaching the water. Take the center measurement from the top to the bottom of the hull. stream
My family and I used it to fish, ski (yes, you can ski behind a pontoon boat), and cruise the lakes near our home. 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. To achieve this, the motor itself has to be attached at the correct height. The average transom angle is around 14 degrees. s.setAttribute("type", "text/javascript"); Step 2: Three Variables to Consider The faster your boat, the more critical it is to get the sizing just right. Rebuilt - What You Need to Know, Lower Unit and Sterndrive Break-In Instructions. Measure from the top of the straight edge to the center of the front
This illustration depicts four different outboard mounting height options (courtesy Mercury Marine). mpeSelector: ".pt-mpe",
Guide to Boat Transom Heights - Marine Parts Warehouse e-mail
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The how to measure the shaft length of an outboard motor is a question that many people have asked. 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. If it measures between 17 and 22, youll want to go with a long shaft motor. To break it down a bit more for you: Short shafts are 15-inches long. 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. (616) 364-0666, On all contiguous US part orders over $100. (function (d) { "brackets". Simply start with the engine in idle, followed by trimming the motor out by one-half to full trim. And thats usually the case since the electric outboards are designed with larger and more efficient propeller that needs longer shaft. } You can find your Mercury outboard model code on an ID plate or sticker. How high exactly do you have to raise the transom?-. The brackets can add 1 inch to the overall mounting height of the outboard. Smaller boats may use adjustable jack plates that can be changed to fit any outboard. var addy_textd53b59933f6c3f2e8b59f1b4a6d41fa5 = 'info' + '@' + 'vanssports' + '.' + 'com';document.getElementById('cloakd53b59933f6c3f2e8b59f1b4a6d41fa5').innerHTML += '
'+addy_textd53b59933f6c3f2e8b59f1b4a6d41fa5+'<\/a>'; A: Any boat that has a 21 to 27 inch aft transom will need an extra long shaft outboard. The greater the number, the more the drive may sway (also called tuck under or negative trim). However, the motor should not be raised more than 5 inches above the standard position. Like Westshore Marine & Leisure on Facebook! A reversetransom that sits too high can impact the propellers of the motor and motor bracket. The point where these measurements intersect is your centerline. Higher mounting decisions should be left to the professionals. Outboard Motor Shaft Length: How do I measure? Always weigh the risks of making adjustments. 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. Cutting the transom down is the only legal method to utilize a short shaft engine on a tall transom. The cookie is used to store the user consent for the cookies in the category "Other. Add the two measurements and you get 6 1/2". It varies between different motors and boats. The average transom angle is around 14 degrees. See diagram below. 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. %PDF-1.7
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. 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. Re: Dinghy with a long shaft motor? It is very versatile as it generally . var prefix = 'ma' + 'il' + 'to'; To measure the transom height, measure from the center on for transom (rear of the boat). This is a measurement that has been used for BassCats, I'm
Raising the motor increases the speed of the boat while decreasing the effort needed to turn the boat. Some may call it a standard length while others may call it a short or a long shaft. 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. The first step is to determine the height of your boat's transom. Charles Plueddeman is Boats.com's outboard, trailer, and PWC expert. The form of a boats transom varies depending on the manufacturer and model. The transom is the flat vertical section at the rear of the boat. ensure that your measurement is accurate. (function () { Check the literature about your model boat online, and you may be surprised to find that the number is published for you. 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. With such an important, long-term, and expensive upgrade, its never a bad idea to double-check. Any questions? To do so, you will want to measure at the exact center of the transom from the very top to the very bottom. This placement is not only recommended but it will give you the best performance compared to something that is too long or too short. The shaft length for outboard motors has nothing to do with the water line. For example, you can have the Mercury outboard shaft length by model code. Owners of bass boats, RIBs, or offshore fishing boats need to get this right. Analytical cookies are used to understand how visitors interact with the website. What Is a Transom? Where Onboard a Boat is It Located? To do so, measure from the stern (back) of the boat to the midpoint of the hull on both sides. Generally, the anti-ventilation plate on most engines is aligned with the bottom of the vessel. 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. Copyright 1999-2023 Boats Group. 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 prop will be in cleaner, harder water as it advances farther aft, making it more efficient. Eq*^?6R83e+j}UY.(M7k]~4g)g ~wmS{ O7t/o(W|X? If you have an outboard motor, the distance from one end to another will be found on the side or on a label near its bottom. If it measures 15" or with in a inch of that you will need a short shaft outboard. These allow the mounting of a standard length outboard behind the transom. the aluminum plate on top of the transom), to the bottom of the motor
Step 4. (Putting a
This allows the engine to idle without the flow of the exhaust being restricted. Simply start with the engine in idle, followed by, If you decide to make some custom adjustments we have the. The clamp bracket on the latest Mercury Four-Stoke-model outboards has five mounting bolt holes spaced .75 inches apart. var path = 'hr' + 'ef' + '='; If it measures between 17 and 22, you'll want to go with a long shaft motor. Boat hulls are designed in three basic types that range from slow displacement and semi-displacement hulls to the fastest planing hulls. And the rule of thumb is that you should keep the cavitation plate level with the bottom or keel of the boat. height (that I'm aware of); probably the most common is:
One of the great things about an outboard motor is how versatile it is. (127 mm). Long shafts are 20-inches long. This website uses cookies to improve your experience while you navigate through the website. Advertisement cookies are used to provide visitors with relevant ads and marketing campaigns. There Thats it. disregard the "hooks" at the front of the
motor brackets
Well, raising the outboard motor can be an easy task for you.
Transom Outboard Engine Position - YouTube The height of the boat transom dictates the size of the outboard motor. It is extremely important that the boater understands the significance of the transom's height. I would ask you to go back and measure the transom of your boat. maxTerm: 36, Doing so, will put the propeller right below the boat. This exhaust port should be about 1 inch above the water line when the boat is idling. The pressure behind your hand dropped as you slid your hand back and forth through the water. Attention: Remember to measure the outboard shaft length straight up and down instead of measuring along the transom. priceSelector: ".price--withoutTax, span.price.price--withTax", If you decide to make adjustments, please consult a marine engine dealer about the boatdesign. 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. This cookie is set by GDPR Cookie Consent plugin. This is measured by the propeller shaft being parallel to the vessels bottom. If you are running a slower boat, the exact location of the ventilation plate is less important. 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. If you go too short your more than likely going to cavitate and loose power.
Engine height with stepped hull at transom - before I screw things up What matters is the actual measurement in the specifications, not the name. 12 Small Fishing Boat Accessories to Buy Today. logoColor: "original", Some fishing boats can handle the motor being underwater. In step 3, add another 10 cm (4") to the previous calculation in order to develop the ideal shaft length. Measure from the top of the transom to the bottom of the hull.
LOYALHEARTDY Outboard Motor 6 HP 2-Stroke Inflatable Fishing Boat 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. 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. 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. Among them will be first-timers or those who have recently purchased their boats. If it measures anywhere from 17" to around 22", then your going to want to go with a long shaft motor. Outboards designed for saltwater applications usually have longer shafts. 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. s.setAttribute("href", "https://cdn.paytomorrow.com/css/pt-mpe.min.css"); High powered boats usually only come in long and extra-long variants. The transom is the rear wall of the boat where the outboard engine is mounted in the middle. These cookies help provide information on metrics the number of visitors, bounce rate, traffic source, etc. The mounting height of the outboard engine is the equivalent of the distance between the base of the motor and the top of the propeller. Most of the time, adding a hydrofoil to an outboard improves performance. Why wont Touch ID be under the screen in the iPhone 15 and iPhone 16? This restriction includes most fishing boats and longer sailboats. Oftentimes you will want to adjust the outboard shaft length in order to improve the boat performance such as speed. I would also recommend finding your maximum horsepower rating which is located on the yellow coast guard tag towards the back of your boat.
xmlHttp.setRequestHeader('Content-Type', 'application/json'); 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. var ptScript = "https://cdn.paytomorrow.com/js/pt-mpe.min.js"; Measuring the shaft length can be done in various ways, but the most common way is by using a tape measure. if (PayTomorrow) { ), and place it on the bottom of the pad in the center. If your outboard motor height. Gear case sits just below or at the hull depth due to the deep v. These are vertically aligned so the boater can make adjustments. Each one has a totally different effect on the boats performance. What is Transom Height? With this in mind, how can I determine if my outboard has a short or long shaft? No one wants to have issues with a new transom or boat repairs. Outboard shaft length plays a crucial role in the performance of your boat. Then test the boat and adjust the height, if necessary . Lubrication System Engine Oil Mixed Gasoline. of the "bullet" on your lower unit. In addition, motor totes will not harm the finish of the lower unit. 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. To make the yard stick long enough to measure the length of all the clubs, tape the ruler to the top. It is extremely important that the boater understands the significance of the transoms height. Trimming in, trimming down, and trimming out are all terms that a beginning boater should learn. The general guideline for longer shaft outboards is that the transom height should be at least 20 inches (50,8cm) above the waterline. Step 3: Add another 10 cm (4'') to the previous calculation for the final ideal shaft length. 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. See When St. Peters Basketball Games Are Today! hulls, such as Allisons, Bullets, Strokers, etc., this measurement could
How to Measure a Boat Transom - Gone Outdoors It is unsafe to have the engine block too close to the water on a low transom. var BCData = {"csrf_token":"d7ecb6b56891bb66aee12dbc01a80162b3ed582c1acbe30f16fc9f1b2abc362f"}; This also means it can affect the safety of the boat.
PDF Outboard shaft lengths and transoms - Boat Builder Central Displacement hulled vessels like sailboats and workboats can benefit from a little more space between the hull and cavitation plate, but not much. Beginning boaters should be aware of the boats measurements. Over time, Boating Hub has grown into a resource for boating enthusiasts around world. The Effects of Standard, Lower and Higher Mounting. Beginning boaters should be aware of the boats measurements. So from there, I will try to help out by asking questions about your boat such as what type it is and the length. The cookie is used to store the user consent for the cookies in the category "Performance".
How to Raise Outboard Motor on Transom? - Raising the Outboard Motor Take your time and understand your boat and your entire transom. MarinePartsMan.com also says that V6 bass-boat engines have a 20-inch shaft. But, how do you measure it? Keep these numbers in mind if you ever have a need for a new outboard motor for your boat. Save my name, email, and website in this browser for the next time I comment. The amount of degrees the transom leans back from vertical is known as the transom angle. (We wont go into name-calling here, but the actual term for the cavitation plate is an anti-ventilation plate.) It is extremely important that the boater understands the significance of the transoms height. But in many cases, its a little more complicated than that alone. A2: Instead of changing to the short outboard shaft, you can try the Jack Plate first. Always weigh the risks of making adjustments. Which Navigation Lights Does Your Boat Need? var xmlHttp = new XMLHttpRequest(); Some outboards have a serial number that tells you which shaft length to go for. Triton. Extra-extra long shafts are 30-inches long. This is the dimension you'll need when selecting a width for your outboard motor's mounting bracket. As mentioned above, the operation of the propeller relies on the transom height. displayMicroOffers: false,
How to Find Your Shaft Length | ePropulsion