It is possible that the motor could hang low while transporting on the boat trailer causing future boat repairs. Its still smart to measure it yourself though, just in case, the design changed over the years. storeDisplayName: "Marine Parts Warehouse", %
The faster your boat, the more critical it is to get the sizing just right. xmlHttp.setRequestHeader('Content-Type', 'application/json'); 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. 4 0 obj
What types of boat need an extra long shaft? debugMode: false, It is where the outboard is mounted, and some boat owners place the name of the boat. If you have a small boat with a 15 to 17 inch aft transom, youll most likely need a short shaft outboard. A transom saver, which can change the spacing between the lower unit and the trailer, negates some of the support. How can you figure out what your transom angle is? var h = d.getElementsByTagName("head"), To achieve this, the motor itself has to be attached at the correct height. For over five years he has worked as a newspaper reporter and historic researcher. s = d.createElement("script"); This could also effect your travelling capabilities on the boat trailer. height (that I'm aware of); probably the most common is:
It moves an outboard up and down to optimize performance and enable a boat to venture into shallower water than it might otherwise. As a result, the issue is whether my boat need a short shaft or long shaft motor. Before we start measuring the outboard shaft length, lets get it clear about whats referring to when we talk about the outboard shaft length. and I'll explain it better, (or point you to someone that can help. These are vertically aligned so the boater can make adjustments. You need JavaScript enabled to view it. It varies between different motors and boats. Mounting the outboard motor in accordance with the industry standards is important. Boat transom angles play a pivotal role in the flexibility of the boats trimming abilities. If you said something smaller than that, thats where it can get tricky. would be more accurate.) Since the length of the shaft of your outboard is associated with the size boat, smaller engines will generally have shorter shafts. The vertical distance between the interior of the clamp and the cavitation plate is the shaft length specified by the outboard manufacturer. 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. But, how do you measure it? The motor is what powers the boat so the two go hand-in-hand. 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. #2. 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. 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. It is extremely important that the boater understands the significance of the transom's height. Not to measure boat speed, but to gauge the mounting height of the outboard motor on the boat transom. For vessels with transom-mounted outboards, you can easily figure out which type of outboard you need to get.
WHAT LENGTH OUTBOARD DO YOU REALLY NEED? - Van's Sport Center Then open up the clamp bucket. 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. 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. Among them will be first-timers or those who have recently purchased their boats. (updated
In lower mounting, the engine is set lower than the recommended standard. Place the bracket on the transom to the left of the main outboard or rudder. Each one has a totally different effect on the boats performance. Analytical cookies are used to understand how visitors interact with the website. Owners of bass boats, RIBs, or offshore fishing boats need to get this right. A: Any boat that has a 21 to 27 inch aft transom will need an extra long shaft outboard. If it measures between 17 and 22, youll want to go with a long shaft motor. Generally, the anti-ventilation plate on most engines is aligned with the bottom of the vessel. If you decide to make adjustments, please consult a marine engine dealer about the boatdesign. So how to determine the outboard shaft length? If it measures between 17 and 22, you'll want to go with a long shaft motor. If your boat planes, pay extra attention to getting the shaft length as close to perfect as possible. 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. 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. Or it can have an angle degree as high as 30. Smaller inflatables and dinghies needshort shaft motors, whilst bigger boats require long or, in some circumstances, extreme long shaft versions. The average transom angle is around 14 degrees. The form of a boats transom varies depending on the manufacturer and model. 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. This measurement is primarily designed for single motor propulsion. Outboard shaft length plays a crucial role in the performance of your boat. These cookies will be stored in your browser only with your consent. Where Onboard a Boat is the Transom Located and More About Transom Heights A propeller operates based on the height of the transom. Its where the outboard motor is attached, and its also where some boat owners put the boats name. } 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.
Tightening Torque for Engine. These allow the mounting of a standard length outboard behind the transom. 7. Then adjust the motor in a higher hole with a flat head screwdriver. This also means it can affect the safety of the boat. (127 mm). Mounting the outboard a little bit lower than the standard point could avoid the possible ventilation and slip on acceleration. priceSelector: ".price--withoutTax, span.price.price--withTax", 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. By clicking Accept, you consent to the use of ALL the cookies. Repowering your boat is one of the most expensive upgrades you can make. parallel with the straight edge. Necessary cookies are absolutely essential for the website to function properly. 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. 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 dont have to be a mathematician to determine the correct boat transomangle. The transom is the boats flat vertical part at the back. For really big boats, the biggest and baddest six- or eight-cylinder outboards can have extra-extra long shafts up to 30 inches. In lower mounting, the engine is set lower than the recommended standard. It was a 23-foot Crestliner Grand Cayman pontoon boat. logoColor: "original", 1 0 obj
Proper Mounting Height for an Outboard - Gone Outdoors Should I take the raft onto the water and measure the exact distance from the top of the transom to the water line? Among them will be first-timers or those who have recently purchased their boats. var addy_textd53b59933f6c3f2e8b59f1b4a6d41fa5 = 'info' + '@' + 'vanssports' + '.' + 'com';document.getElementById('cloakd53b59933f6c3f2e8b59f1b4a6d41fa5').innerHTML += '
'+addy_textd53b59933f6c3f2e8b59f1b4a6d41fa5+'<\/a>'; What matters is the actual measurement in the specifications, not the name. Amazon has plate extensions to allow adjustments without buying a new motor: T-H Marine Jack Plate Extension. As with anything, there are exceptions to the rule. Brackets are also handy for boats that do not have flat transoms, like canoe-stern sailboats or fan-tailed motor vessels. There are also specialty motor shaft lengths.
How to Raise Outboard Motor on Transom? - Raising the Outboard Motor An outboard motor can drive just about any sort of boat with proper mounting. Attention: Remember to measure the outboard shaft length straight up and down instead of measuring along the transom. 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. Extra-long shafts are 25-inches long. The transom angle is the vertical incline of the transom and is measured in degrees.
Read the measurement on the transoms bottom. endobj
As summer approaches there will be more boaters taking to the water. Expectedly, when the transom angle is zero, it means it is flat. 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. I run a 9.9 Mercury Bigfoot 20" shaft off the swim platform of my 89 Trophy 2160. 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. In addition, motor totes will not harm the finish of the lower unit. 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. There are instances where a lower mount may be okay. Boats that use longer outboard shafts include: You must be still in the blue about that matter. With some boats I have a pretty good idea as to what length motor should be hung on them. 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. And thats usually the case since the electric outboards are designed with larger and more efficient propeller that needs longer shaft. The engine must be linked to the transom at the proper height for a propeller to best meet specific boating demands. The cookie is set by GDPR cookie consent to record the user consent for the cookies in the category "Functional". To break it down a bit more for you: Short shafts are 15-inches long. if (PayTomorrow) { Cavitation plates are used on the bottom components of boats to help them operate better. The boater must also consider if the boat transom support is designed to bear the weight of a higher mount. Will Charpentier is a writer who specializes in boating and maritime subjects. This measurement was approximately 4". The cookies is used to store the user consent for the cookies in the category "Necessary". Trimming in, trimming down, and trimming out are all terms that a beginning boater should learn. I live for the weekends when I can go out on the water and escape the stress of life on land. There is a simple test to see if your outboard motor is set at the best height. 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. 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. Check out some hot FAQs to help you get the proper outboard shaft lengths. This number will likely be shorter than that for a single-engine installation since you do not necessarily measure to the point of the keel. Smaller 12-14 foot boats can require either a short or long shaft outboard depending on the style of the boat and the brand. Variables to consider when determining the mounting height include the size and style of the boat and the length of the outboard motor's shaft. An inch or two probably wont make a big difference, but any more than that will lead to trouble. Buying a boat can be an exciting purchase. endobj
What is a Transom Saver And Do I Need One? - Boat Safe Any questions? <>
It also cuts into speed and fuel efficiency. <>/ExtGState<>/XObject<>/ProcSet[/PDF/Text/ImageB/ImageC/ImageI] >>/MediaBox[ 0 0 595.2 841.8] /Contents 4 0 R/Group<>/Tabs/S/StructParents 0>>
PDF Outboard shaft lengths and transoms - Boat Builder Central 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. "brackets". A yardstick will help you determine if your outboard engine is at the right height. The boat transom can be flat with zero degree angles. Outboard Motor Shaft Length: How do I measure? 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. Then, you can pick the right engine. This was the height of my 225 Yamaha on my TR21
It is very versatile as it generally . xmlHttp.open('POST', 'https://bes.gcp.data.bigcommerce.com/nobot'); I show you how to consistently measure your prop to pad height. If youre going the other way around and trying to figure out how long the shaft on your outboard is, measuring it is equally easy. Before we get started lets see what a boat transom is and what it does. Spark Plug 25.0nm(18.4 Ft-lb) (2.55 Kgf-m) The motor length corresponds to the transom height of the boat, measured from the keel to gunwale at the transom. MarinePartsMan.com also says that V6 bass-boat engines have a 20-inch shaft. The correct shaft length for your boat depends on a few factors. 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. of the motor off the transom
There All boats are different, and the motor manufacturers produce a variety of standard lengths. Propshaft in
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. Measure the area of the transom directly where the engine will be mounted. var ptScript = "https://cdn.paytomorrow.com/js/pt-mpe.min.js"; The transom angle is the vertical incline of the transom and is measured in degrees. Theyre also useful if the back of your boat has a non-standard measurement. To do so, take a measurement from the very top to the very bottom of the transom in the precise center. Well, raising the outboard motor can be an easy task for you. To measure the transom height, measure from the center on for transom (rear of the boat). Attention: Remember to measure the outboard shaft length straight up and down instead of measuring along the transom. With it comes a lot of responsibility and new things to learn includingboat maintenanceand boat basics. Youll need a short shaft outboard if its 15 or less than an inch shorter. Since the ventilation plate & foil are burried under water it is obviously too low. 5/rC,aQhsK@Q.
LOYALHEARTDY Outboard Motor 6 HP 2-Stroke Inflatable Fishing Boat jackplate to a point level with the top of the transom. 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 height of the transom is calculated by measuring from the bottom of the hull to the top of the transom, using the center line. If you are looking to repower, they may be able to offer some sage advice. 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. Ten years ago I bought my first boat. Typical motor lengths include the following. With a motor tote, the outboard and boat move as one, independently of the trailer, so there are no concerns about the boat shifting on the trailer, he says.
This alone can outweigh the negatives when deciding to adjust the mount upwards. We use cookies on our website to give you the most relevant experience by remembering your preferences and repeat visits. function mpeInit() { Happy boating! 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. 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. High powered boats usually only come in long and extra-long variants. The average transom angle is around 14 degrees. If it measures anywhere from 17" to around 22", then your going to want to go with a long shaft motor. loadScript(ptScript); The transom is the "back wall" of your boat, the most rearward part of your hull. %PDF-1.7
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. The cavitation plate is the horizontal surface of the lower unit immediately above the propeller. He is also a certified marine technician and the author of a popular text on writing local history. I hope this helps someone out in their search for a new or newer outboard this season. However, the motor should not be raised more than 5 inches above the standard position. The outboard shaft length is the vertical distance between the top of the mounting clamp bracket and the bottom of the cavitation plate (aka the ventilation plate).
What Is Boat Transom Height? | Gone Outdoors | Your Adventure Awaits <>/Metadata 127 0 R/ViewerPreferences 128 0 R>>
Another important measurement is the transom angle. If you went too long it would still work but it may lack in performance. Take a long straight edge, (long carpenter's level or long
This cookie is set by GDPR Cookie Consent plugin. He is a Knowing the width, height and depth of your transom allows you to make several important decisions when selecting or purchasing a new outboard. function loadScript(script) { When you measure the width of the stern, mark the center with a grease pencil. Take the center measurement from the top to the bottom of the hull. Look at the part of your motor that would be
Copyright 2017 Dealer Spike All Rights Reserved. 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. If you have a question or need additional information. The transom is the flat vertical section at the rear of the boat. To make the yard stick long enough to measure the length of all the clubs, tape the ruler to the top. As you can see, the measurement is about 2 1/2". Step 3: Add another 10 cm (4'') to the previous calculation for the final ideal shaft length. With such an important, long-term, and expensive upgrade, its never a bad idea to double-check.
Its important to note that manufacturers call their models different things. Your goal is to measure how the outboard will sit, so start from the clamping plate and follow the centerline of the hull. A reverse transom that sits too high can impact the propellers of the motor and motor bracket. Lubrication System Engine Oil Mixed Gasoline. 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. For most boaters this is a no brainer, but for the novice or inexperienced boater it may be a tougher question. 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. h[0].appendChild(s); 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). With the long side (22 1/2), place a carpenters square ) in opposition to the keel. Mounting the outboard motor in accordance with the industry standards is important. It doesnt matter if you have a fiberglass boat, bay boat, big or small boat. However, there may be times when a boater strays away from these recommendations. If you are running a twin-engine setup, then measure the same distance from each clamping plate to the bottom of the hull. var h = d.getElementsByTagName("head"), Or measure from the main engine prop up to the water line? No one wants to have issues with a new transom or boat repairs.
A long shaft engine requires a height of 20 and extra-long shaft engines will need a transom height of 25. 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. The general guideline for longer shaft outboards is that the transom height should be at least 20 inches (50,8cm) above the waterline. Later in the article is an image that shows you exactly where to measure. My family and I used it to fish, ski (yes, you can ski behind a pontoon boat), and cruise the lakes near our home. Measure from the top of the transom to the bottom of the hull. The propellers will also have trouble reaching the water. The height of the boat transom dictates the size of the outboard motor. the aluminum plate on top of the transom), to the bottom of the motor
How the outboard will sit on the back of the boat depends on how the transom is designed. Follow Westshore Marine & Leisure on Wordpress!
The Best Way to Measure Prop to Pad | How to measure Outboard Motor Height up to the bottom of the motor brackets, (as in #1). The shaft length for outboard motors has nothing to do with the water line. not sure that it's still used. document.getElementById('cloakd53b59933f6c3f2e8b59f1b4a6d41fa5').innerHTML = ''; 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.
To do so, you will want to measure at the exact center of the transom from the very top to the very bottom. If your boat is newer and the manufacturer is still in business, you might also want to try to give them a call.
These are vertically aligned so the boater can make adjustments. Most of the time, adding a hydrofoil to an outboard improves performance. Place the clubs bottom on the ground as though it were going to be used to strike a golf ball. Some fishing boats can handle the motor being underwater. Measure from the top of the transom to the bottom of the hull. steel ruler, etc. Required fields are marked *. Youll also want to pay attention when youre in shallow water because your prop will be lower than normal. displayPrimeOffers: true, 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. The greater the number, the more the drive may sway (also called tuck under or negative trim). These cookies track visitors across websites and collect information to provide customized ads. Commonly, the transom angle ranges from 0-30 degrees, with the average transom angle set at 14 degrees. When trimming your motor, they provide you a greater bow response.