It varies between different motors and boats. With the long side (22 1/2), place a carpenters square ) in opposition to the keel. As you can see, the measurement is about 2 1/2". Pretty easy to figure out but like I said its crucial to pairing a motor with a boat. 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. The faster your boat, the more critical it is to get the sizing just right. displayPrimeOffers: true, This cookie is set by GDPR Cookie Consent plugin. This provides seaworthiness and offers maximum protection from large seas. Triton. Boaters who consider going with a higher mount can see increased speeds. A: Any boat that has a 21 to 27 inch aft transom will need an extra long shaft outboard. The how to measure the shaft length of an outboard motor is a question that many people have asked. So from there, I will try to help out by asking questions about your boat such as what type it is and the length. steel ruler, etc. If your outboard motor height. So you should just measure the height of the boat's transom from the center down to the lowest point of the hull, and compare transom height with the outboard shaft length numbers. This restriction includes most fishing boats and longer sailboats. On this type of boat, if you are in doubt, default to the longer-shafted outboard. Mounting the motor lower on the boat transom can create excessive spray, increase case drag, reduce underwater clearance, and negatively impact faster boats. Other boats that need long shafts are. With a jack plate, you can mount it exactly where you want it. Generally, short shaft outboards are 15 inches, long shaft outboards are 20 inches, and extra-long outboards are 25 inches. 12 Small Fishing Boat Accessories to Buy Today. the propshaft below or above the pad. Move the bracket as close to the center of the transom as possible while still maintaining clearance to allow the main outboard or rudder to reach its full range of motion without contacting the kicker motor. 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. Repowering your boat is one of the most expensive upgrades you can make. window.dataLayer = window.dataLayer || []; However, youll notice a little increase in drag and a decrease in top-end performance. since 1986. On the downside, a higher mount can interfere with the boaters steering capabilities. logoColor: "original", At least if its too long you can raise the motor or "build up" your transom. maxMicroAmount: 0.0, Shaft lengths are available in increments of 5. stream
Extra-extra long shafts are 30-inches long. Most transom savers can support up to a 150HP motor, which is sufficient for most regular boats. The height of the boat transom dictates the size of the outboard motor. There PayTomorrow.mpeInit({ Typical motor lengths include the following. If you decide to make some custom adjustments we have theexperience and know-howto make it happen. 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. Engine Oil Mixing Ratio Fuel 50: Engine Oil 1. For really big boats, the biggest and baddest six- or eight-cylinder outboards can have extra-extra long shafts up to 30 inches. Read the following to get the optimal shaft length for outboard motors! (616) 364-0666, On all contiguous US part orders over $100. s.setAttribute("src", script); Measure from the top of the transom to the bottom of the hull. As a yacht designer and boater, I prefer longer shafts. If the height of the boat transom is off it can cause major issues. (127 mm). Save my name, email, and website in this browser for the next time I comment. Safely but briskly accelerate. When you measure the width of the stern, mark the center with a grease pencil. This is a measurement that has been used for BassCats, I'm
Because of the increased friction, cavitation reduces efficiency. 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. How the outboard will sit on the back of the boat depends on how the transom is designed. Problems with getting the ventilation plate too low include slower hole-shot and lower top-end speeds. Add yours in the comment and Ill get back to you asap. Simply start with the engine in idle, followed bytrimming the motor out by one-half to full trim. You reply, "Im not sure, I think its a long".
Measuring Motor Height - BassBoat Central How to Measure Shaft Length on Outboard Motor? - TrollinMotorsGuide Here is a picture that shows you exactly where the outboard motor shaft length stands: Usually the shaft length for outboard motors falls into the following 4 sizes: In practice, you may find the outboard motor shaft length varies among different brands and manufacturers like the Honda,Suzuki, Yamaha, Torqeedo, etc. 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. We also use third-party cookies that help us analyze and understand how you use this website. Lubrication System Engine Oil Mixed Gasoline. 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}'); (Putting a
Tightening Torque for Engine. This website uses cookies to improve your experience while you navigate through the website. They operate as a planing surface, allowing your boat to climb to the top more quickly. Beefier jack plates can be fitted should a boater be looking to mount an outboard with a shorter shaft than their transom demands. 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.
Installing a Kicker Motor Bracket - Gone Outdoors The collapsing bubbles are loaded with extremely low-pressure water vapor, which causes damage to a variety of surfaces as they collapse. Picking the right shaft length for your outboard is an essential step in getting the best performance from your boat. If you decide to make adjustments, please consult a marine engine dealer about the boat design.
What Is a Transom? Where Onboard a Boat is It Located? Having the cavitation plate a bit lower than the transom is preferable to having it too high. Analytical cookies are used to understand how visitors interact with the website. See When St. Peters Basketball Games Are Today! This email address is being protected from spambots. s.setAttribute("href", "https://cdn.paytomorrow.com/css/pt-mpe.min.css"); C Cheaptoon Cadet Joined Aug 4, 2010 Messages 28 Aug 24, 2010 #4 Re: Motor height on pontoon? (Any measurement given as "off the transom"
Another important measurement is the transom angle. Gear case sits just below or at the hull depth due to the deep v. Having the cavitation plate too low will cause excess drag and reduced performance at high speeds. Place the point of a yardstick at the middle of the top of the boat transom. 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. This is handy if youre shopping for second-hand outboards or looking to sell the one that came with your boat. To achieve 35 mph with a 6 hp engine, the total weight is 135 lbs (boat motor fuel passengers). This is probably the worst case scenario out of the two. boats.com is part of the Boats Group Network. There are 2 steps to help get a relatively accurate figure. This allows the engine to idle without the flow of the exhaust being restricted. This could also effect your travelling capabilities on the boat trailer. The boat transom can be flat with zero degree angles. Step 2 requires the propeller's radius (check the user manual and then the technical drawing). It can also improve the experience of driving a faster boat.
How To Measure Outboard Motor Shaft Length [Long v Short] - Boating Hub It will ensure that the outboards trim will be effective, and it will save you gas too. Basically, there are three main ways to measure motor
When fighting waves from the stern, a 20-inch transom is considerably safer. A deep Vee hull will result in a different measurement than a flatter . Beginning boaters should be aware of the boats measurements. Check the literature about your model boat online, and you may be surprised to find that the number is published for you. These are vertically aligned so the boater can make adjustments. Check out some hot FAQs to help you get the proper outboard shaft lengths. 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. 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). You dont have to be a mathematician to determine the correct boat transom angle. Generally, the anti-ventilation plate on most engines is aligned with the bottom of the vessel. Follow Westshore Marine & Leisure on Wordpress!
help with shaft length for a kicker - iboats Boating Forums The flat part of the bracket that rests on the transom when mounted will give you the same point of reference as the transom does on the boat. High powered boats usually only come in long and extra-long variants. If so, send me an
Of course, its always best to go with standard practices when choosing thebest boat engine. By clicking Accept, you consent to the use of ALL the cookies. Take the center measurement from the top to the bottom of the hull. Whether you already own a boat or looking for your first watercraft we are here to service your needs. x\[D~OUCO6[j](l%ay <8cylY{.L2s#]~U6A|Wj]-oo|mubqY6wbY_|!>Z8(RB:RHeTzOGO_=~t\ When the boattransom is too low, the motor could end up underwater. No one wants to have issues with a new transom or boat repairs. The motor length corresponds to the transom height of the boat, measured from the keel to gunwale at the transom. Smaller boats may use adjustable jack plates that can be changed to fit any outboard. These allow the mounting of a standard length outboard behind the transom. The transom is the flat vertical section at the rear of the boat. gtag('js', new Date()); 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 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. (3) Move horizontally across the chart until you hit the graph curve. Wherever the outboard clamping bracket is, use this as the basis for measurement. straight edge on the top of the transom to "extend" it out
s = d.createElement("script"); To make the yard stick long enough to measure the length of all the clubs, tape the ruler to the top. This will ensure the best performance. All rights reserved. center of the propshaft. Attention: Remember to measure the outboard shaft length straight up and down instead of measuring along the transom. All boats are different, and the motor manufacturers produce a variety of standard lengths. You may wonder how deep your prop should be in the water. s.setAttribute("rel", "stylesheet"); This, however, is not recommended for the beginning boater. If you have a short shaft motor, the distance between the top of the transom and the bottom of the boat should be between 15 and 16 inches. :$I>M W$h"%U_yzIb?]NHg_G|r@nX eTf."SQ https:/. This measurement would be the inches of
The transom angle is the vertical incline of the transom and is measured in degrees. %PDF-1.7
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. To do so, you will want to measure at the exact center of the transom from the very top to the very bottom. disregard the "hooks" at the front of the
It doesnt matter if you have a fiberglass boat, bay boat, big or small boat. Youll also want to pay attention when youre in shallow water because your prop will be lower than normal.
Mounting kicker motor - General Discussion Forum | In-Depth Outdoors 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. | Sitemap, The Marine Parts Warehouse Outboard Museum, OBR Powerhead / Shortblock Warranty Claim Form, Remanufactured vs. 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.
} Any questions?
The clamp bracket is designed so that the engine's mounting height on the transom can be adjusted higher than standard. The correct shaft length for your boat depends on a few factors. Other uncategorized cookies are those that are being analyzed and have not been classified into a category as yet. Smaller 12-14 foot boats can require either a short or long shaft outboard depending on the style of the boat and the brand. Whether your on a pontoon boat, fishing boat, or speedboat boating is always one of the best times you can have. The vertical distance between the interior of the clamp and the cavitation plate is the shaft length specified by the outboard manufacturer. The shaft length for outboard motors has nothing to do with the water line. The cookies is used to store the user consent for the cookies in the category "Necessary". This is measured by the propeller shaft being parallel to the vessels bottom. My family and I used it to fish, ski (yes, you can ski behind a pontoon boat), and cruise the lakes near our home. a Detwiler manual jackplate. xmlHttp.open('POST', 'https://bes.gcp.data.bigcommerce.com/nobot'); The lowest point will likely be directly under your drain plug if youve got one. Some outboards have a serial number that tells you which shaft length to go for. If you decide to make adjustments, please consult a marine engine dealer about the boatdesign. want to measure from the transom to the flat part of this bracket,
The cavitation plate is the horizontal surface of the lower unit immediately above the propeller. Owners of bass boats, RIBs, or offshore fishing boats need to get this right. What's the best height for my boat motor? You dont have to be a mathematician to determine the correct boat transomangle. 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.
Transom Outboard Engine Position - YouTube It is where the outboard is mounted, and some boat owners place the name of the boat. out the confusion. However, the shaft length for smaller boats could be long or short depending on its style, speed requirement, etc. e-mail
Bass boats, ski boats, or center cockpit vessels will want to double-check their measurements to get it just right. It is unsafe to have the engine block too close to the water on a low transom. It also cuts into speed and fuel efficiency. *The Factors indicates the adjustment affected by on your boat type, the outboard working environment, and the transom distance as discussed above. Each one has a totally different effect on the boats performance. What is the Virtual Sundance Film Festival? Why wont Touch ID be under the screen in the iPhone 15 and iPhone 16? Outboard motors can be fitted to a variety of boats, so manufacturers have standardized their engines to go on virtually anything. The greater the number, the more the drive may sway (also called tuck under or negative trim).
How Low Should a Motor Set on a Pontoon Boat? (Explained) This alone can outweigh the negatives when deciding to adjust the mount upwards. Place the rulers end on the ground behind the club and let the club to rest on top of it. 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. All you need to do is measure how much to rise. The average transom angle is around 14 degrees. There are a series of four to six holes at the top of the bracket, and the lower bolts actually fit into slots. All things considered, sticking with the industry standard is best for the beginner. A long shaft engine requires a height of 20 and extra-long shaft engines will need a transom height of 25. 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. It can also improve the experience of driving a faster boat. ), and place it on the bottom of the pad in the center. This illustration depicts four different outboard mounting height options (courtesy Mercury Marine). Next, measure from your centerline to where the outboard will be mounted on each side. Finding the right size is a matter of looking at what youve got and taking out the measuring tape.
How To Mount An Outboard Motor Properly - Start to Finish! It is extremely important that the boater understands the significance of the transom's height. })(); Since the ventilation plate & foil are burried under water it is obviously too low. Use the mounting bracket on the motor to know where it will sit on the boat. It does not store any personal data. Depending on the manufacturer, size names might change. A retired ship captain, Charpentier holds a doctorate in applied ocean science and engineering. former editor at Boating Magazine and contributor to many national publications 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. Theyre also useful if the back of your boat has a non-standard measurement. The height is approximately six inches higher than with a propeller. For over five years he has worked as a newspaper reporter and historic researcher. Say the 20 shaft is a long shaft length for gas engines, but it is a short shaft length for electric outboard motors. 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. }) } }); })(document); The cookie is used to store the user consent for the cookies in the category "Analytics". On the downside, a higher mount can interfere with the boaters steering capabilities. If it measures anywhere from 17" to around 22", then your going to want to go with a long shaft motor. As with anything, there are exceptions to the rule. Copyright 1999-2023 Boats Group. 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.
If you have a question or need additional information,contact ustoday. If you are running a slower boat, the exact location of the ventilation plate is less important.