With a jack plate, you can mount it exactly where you want it. This also means it can affect the safety of the boat. 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. endobj
Finding the right size is a matter of looking at what youve got and taking out the measuring tape. The cookie is used to store the user consent for the cookies in the category "Other. All things considered, sticking with the industry standard is best for the beginner. 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? Say the 20 shaft is a long shaft length for gas engines, but it is a short shaft length for electric outboard motors. 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. The standard shaft length for most outboard engines less than 125 horsepower is 20 inches. to where the brackets were actually resting on the transom. parallel with the straight edge. You need JavaScript enabled to view it. There 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. 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. 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". 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. 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. 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). Boaters who consider going with a higher mount can see increased speeds. Step 2 requires the propeller's radius (check the user manual and then the technical drawing). h[0].appendChild(s); This measurement is primarily designed for single motor propulsion. xmlHttp.setRequestHeader('Content-Type', 'application/json'); *The Factors indicates the adjustment affected by on your boat type, the outboard working environment, and the transom distance as discussed above. ensure that your measurement is accurate. Expectedly, when the transom angle is zero, it means it is flat. A big NO. Save my name, email, and website in this browser for the next time I comment. See diagram below. Look at the part of your motor that would be
The boat transom can be flat with zero degree angles. trimming the motor out by one-half to full trim. Again, make sure that you are measuring to the flat part of the brackets;
You can use a longer shaft than recommended and your boat will work fine. If you decide to make some custom adjustments we have theexperience and know-howto make it happen. A1: Broadly speaking, the outboard motor shaft length for pontoon boat, bass boat, or other larger boats should be long shaft. This will be the
If you have already measured you transom tip to bottom to be 20", then if you place aux sdieways to central engine your available transom height will be probably 1"-1.5" " higher and work perfecty. (Any measurement given as "off the transom"
jackplate to a point level with the top of the transom. Beginning boaters should be aware of the boats measurements. will be to the flat part; if you measure to the bottom of the brackets
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. This measurement would be the inches of
I also love helping others, which is why I created this website. If it measures 15" or with in a inch of that you will need a short shaft outboard. With this in mind, how can I determine if my outboard has a short or long shaft? There is a simple test to see if your outboard motor is set at the best height. At least if its too long you can raise the motor or "build up" your transom. As a yacht designer and boater, I prefer longer shafts. But, how do you measure it? 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. "brackets". In the case of a dinghy or johnboat, this point may be the top of the transom. The clamp bracket on the latest Mercury Four-Stoke-model outboards has five mounting bolt holes spaced .75 inches apart. The mounting height of an outboard motor can impact the speed and handling characteristics of the boat. Mounting the outboard motor in accordance with the industry standards is important. While this is the case there is certain saltwater motors that are extra extra long at 30 and 35 shaft. Analytical cookies are used to understand how visitors interact with the website. Step 2: Three Variables to Consider up to the bottom of the motor brackets, (as in #1). Thats a fairly simple list of symptoms, but if your motor is too low, youll probably notice at least one of them. As summer approaches there will be more boaters taking to the water. Not to measure boat speed, but to gauge the mounting height of the outboard motor on the boat transom. My family and I used it to fish, ski (yes, you can ski behind a pontoon boat), and cruise the lakes near our home. The correct shaft length for your boat depends on a few factors. No one wants to have issues with a new transom or boat repairs. Measure from the top of the transom to the bottom of the hull. The outboard comes with mounting holes and brackets. Where Onboard a Boat is the Transom Located and More About Transom Heights A propeller operates based on the height of the transom. mpeInit(); You dont have to be a mathematician to determine the correct boat transomangle. You also have the option to opt-out of these cookies. To sum up, there is a simple calculator of the shaft length for outboard motors: Outboard Shaft Length = Transom Height +/- Factors. Increased RPM and additional horsepower feed the need for speed. Youll also want to pay attention when youre in shallow water because your prop will be lower than normal. This cookie is set by GDPR Cookie Consent plugin. I show you how to consistently measure your prop to pad height. 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). Take your time and understand your boat and your entire transom. Boats with more engine power and weight require longer shaft outboards for better balance. function gtag(){dataLayer.push(arguments);} If you have a question or need additional information,contact ustoday. Offshore vessels are often equipped with a large mounting bracket so that the transom can be left at full height. 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). Should I take the raft onto the water and measure the exact distance from the top of the transom to the water line? Brackets are also handy for boats that do not have flat transoms, like canoe-stern sailboats or fan-tailed motor vessels. To make the yard stick long enough to measure the length of all the clubs, tape the ruler to the top. Some fishing boats can handle the motor being underwater. All rights reserved. Owners of bass boats, RIBs, or offshore fishing boats need to get this right. Is my outboard long or short shaft? It also cuts into speed and fuel efficiency. This cookie is set by GDPR Cookie Consent plugin. Take the center measurement from the top to the bottom of the hull. 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. } This is simply a measurement taken from the top of the transom (top of
Raising an outboard higher on the transom can reduce drag and raise top speed. There is a simple test to see if your outboard motor is set at the best height. I would ask you to go back and measure the transom of your boat. One of the great things about an outboard motor is how versatile it is. However, the motor should not be raised more than 5 inches above the standard position. It doesnt matter if you have a fiberglass boat, bay boat, big or small boat. https://www.bornagainboating.com/Get Your Born Again Boating Clothing! Smaller 12-14 foot boats can require either a short or long shaft outboard depending on the style of the boat and the brand. 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. out the confusion. A: The short answer is Yes. Remember, if you use a longer outboard shaft than you need you will be increasing your draft. would be more accurate.) The vertical distance between the interior of the clamp and the cavitation plate is the shaft length specified by the outboard manufacturer. This, however, is not recommended for the beginning boater. Place the bracket on the transom to the left of the main outboard or rudder. Boat Transom Heights The Beginners Guide, Buying a boat can be an exciting purchase. In step 3, add another 10 cm (4") to the previous calculation in order to develop the ideal shaft length. #1: Height
When you measure the width of the stern, mark the center with a grease pencil. logoColor: "original", Then adjust the motor in a higher hole with a flat head screwdriver. This could also affect your travelling capabilities on the boat trailer. center of the propshaft. Or measure from the main engine prop up to the water line? Knowing how this can affect the overall operation of the boat is a factor to be considered. Since the length of the shaft of your outboard is associated with the size boat, smaller engines will generally have shorter shafts. Most of the standard engined boats it takes shafts that are 15-30inches long. 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. Whether you already own a boat or looking for your first watercraft we are here to service your needs. 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. :$I>M W$h"%U_yzIb?]NHg_G|r@nX eTf."SQ As a result, the issue is whether my boat need a short shaft or long shaft motor. stream
If you went too long it would still work but it may lack in performance. of the motor off the transom
If you have a question or need additional information. An outboard motor can drive just about any sort of boat with proper mounting. The prop will be in cleaner, harder water as it advances farther aft, making it more efficient. 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. Setting Height of Outboard Motor - YouTube 0:00 / 0:46 Setting Height of Outboard Motor nates90 71 subscribers Subscribe 83 Share 63K views 7 years ago #boatservice #outboardmotor. You need JavaScript enabled to view it. Ill also explain the difference between short and long shafts and how they vary by type of boat. Step 4. Amazon has plate extensions to allow adjustments without buying a new motor: T-H Marine Jack Plate Extension. It is possible that the motor could hang low while transporting on the boat trailer causing future boat repairs. A deep Vee hull will result in a different measurement than a flatter . Knowing how this can affect the overall operation of the boat is a factor to be considered. Later in the article is an image that shows you exactly where to measure. You also might not be able to lift the outboard out of the water entirely for storage. 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. A reverse transom that sits too high can impact the propellers of the motor and motor bracket. Its where the outboard motor is attached, and its also where some boat owners put the boats name. Trimming in, trimming down, and trimming out are all terms that a beginning boater should learn. }) } }); })(document); You may wonder how deep your prop should be in the water. No one wants to have issues with a new transom or boat repairs. Tilt your motor until the bullet of the gearcase is
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. With the motor trimmed so that the propshaft is parallel to the keel, the anti-ventilation plate should be just about even with your straight edge, and thus even with the boat bottom at the keel. It is where the outboard is mounted, and some boat owners place the name of the boat. This will keep the prop in the water when the boat pitches in waves, or hobby-horses. 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. Industry standards dictate that for short shaft engines the transom height should be 15. You
Plus, a low transom cut is an invitation for the water to flood the boat. What Types of Documents Can be Sent to your Kindle Library? The general guideline for longer shaft outboards is that the transom height should be at least 20 inches (50,8cm) above the waterline. It is extremely important that the boater understands the significance of the transoms height. This is probably the worst case scenario out of the two. The transom is the "back wall" of your boat, the most rearward part of your hull. He is also a certified marine technician and the author of a popular text on writing local history. All you need to do is measure how much to rise. Keep these numbers in mind if you ever have a need for a new outboard motor for your boat. All boats are different, and the motor manufacturers produce a variety of standard lengths. (127 mm). However, youll notice a little increase in drag and a decrease in top-end performance. s = d.createElement("link"); Problems with getting the ventilation plate too low include slower hole-shot and lower top-end speeds. All things considered, sticking with the industry standard is best for the beginner. Take your time and understand your boat and your entire transom. Two years ago, I bought a Boston Whaler to fish off the coast. 2019s List of the Best Recreational Pontoon Boats for Sale. It was a 23-foot Crestliner Grand Cayman pontoon boat. 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). 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. Step 3: Add another 10 cm (4'') to the previous calculation for the final ideal shaft length. So how to determine the outboard shaft length? For boats equipped with a bracket, calculate the same measurement but based on the bracket and not the transom. We also use third-party cookies that help us analyze and understand how you use this website. Other boats that need extra long shafts are: Read my other articles on outboard motors. This is handy if youre shopping for second-hand outboards or looking to sell the one that came with your boat. 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. For most boaters this is a no brainer, but for the novice or inexperienced boater it may be a tougher question. This provides seaworthiness and offers maximum protection from large seas. Always weigh the risks of making adjustments. A yardstick will help you determine if your outboard engine is at the right height. } Using your existing control box and gauges will save you quite a bit of money in the end. Knowing the width, height and depth of your transom allows you to make several important decisions when selecting or purchasing a new outboard. Beyond motorboats designed for large outboards, you will see outboards hanging on the sterns of everything from small canoes to large cruising sailboats. Follow Westshore Marine & Leisure on Wordpress! Also, how do you determine the length of an outboard transom? Boats that use longer outboard shafts include: e-mail
Measure from the top of the straight edge to the center of the front
Oftentimes you will want to adjust the outboard shaft length in order to improve the boat performance such as speed. It is extremely important that the boater understands the significance of the transoms height. Before we get started lets see what a boat transom is and what it does. since 1986. The performance of these boats depends on quite a lot of factors, but getting the outboard length just right is an essential first step. 5/rC,aQhsK@Q. However, there may be times when a boater strays away from these recommendations. The transom in a boat today is a place to hang your outboard motor. Depending on the manufacturer, size names might change. The cookie is set by GDPR cookie consent to record the user consent for the cookies in the category "Functional". Smaller inflatables and dinghies needshort shaft motors, whilst bigger boats require long or, in some circumstances, extreme long shaft versions. A long shaft engine requires a height of 20 and extra-long shaft engines will need a transom height of 25. %
and I'll explain it better, (or point you to someone that can help. Set the end of the tape on the outside edge of the taffrail at the center and measure inward to the inside edge of the taffrail. A long shaft engine requires a height of 20 and extra-long shaft engines will need a transom height of 25. Chances are the boat was designed with a specific size of outboard in mind. Add yours in the comment and Ill get back to you asap. It can also improve the experience of driving a faster boat. Required fields are marked *. displayMicroOffers: false, The height of the transom is estimated by using the center line to measure from the bottom of the hull to the top of the transom. bassboat can be a bit confusing at times; hopefully this will help sort
clearInterval(interval); Having the cavitation plate too low will cause excess drag and reduced performance at high speeds. We use cookies on our website to give you the most relevant experience by remembering your preferences and repeat visits. the propshaft below or above the pad. steel ruler, etc. straight edge on the top of the transom to "extend" it out
What matters is the actual measurement in the specifications, not the name. minAmount: 300.0, High powered boats usually only come in long and extra-long variants. Picking the right shaft length is mostly a factor of the transom height or the back of the boat. <>/ExtGState<>/XObject<>/ProcSet[/PDF/Text/ImageB/ImageC/ImageI] >>/MediaBox[ 0 0 595.2 841.8] /Contents 4 0 R/Group<>/Tabs/S/StructParents 0>>
(We wont go into name-calling here, but the actual term for the cavitation plate is an anti-ventilation plate.) This placement is not only recommended but it will give you the best performance compared to something that is too long or too short. Beginning boaters should be aware of the boats measurements. Mounting the motor lower on the boat transomcan createexcessive spray, increase case drag, reduce underwater clearance, and negatively impact faster boats. This is the dimension you'll need when selecting a width for your outboard motor's mounting bracket. If your boat planes, pay extra attention to getting the shaft length as close to perfect as possible. To break it down a bit more for you: Short shafts are 15-inches long. Small motors built for sailboats might come in a unique configuration with an extremely long shaft since these are mounted higher off the water. You dont have to be a mathematician to determine the correct boat transom angle. The boat transom can be flat with zero degree angles. For slower boats, its less critical to. relation to pad
A: Any boat that has a 21 to 27 inch aft transom will need an extra long shaft outboard. Necessary cookies are absolutely essential for the website to function properly. So from there, I will try to help out by asking questions about your boat such as what type it is and the length. You reply, "Im not sure, I think its a long". I believe 20 to 21 inches is the optimum length for a lengthy shaft. Keep these numbers in mind if you ever have a need for a new outboard motor for your boat. Then open up the clamp bucket. var BCData = {"csrf_token":"d7ecb6b56891bb66aee12dbc01a80162b3ed582c1acbe30f16fc9f1b2abc362f"}; bracket forward with a straight edge to where you can then measure up
When the boat transom is too low, the motor could end up underwater. This is a measurement that has been used for BassCats, I'm
Because of the increased friction, cavitation reduces efficiency. publicId: "32bf3437d1346295e03ebcf545f9c839", Whats the best height for my boat motor? For really big boats, the biggest and baddest six- or eight-cylinder outboards can have extra-extra long shafts up to 30 inches. The amount of degrees the transom leans back from vertical is known as the transom angle. A long shaft engine requires a height of 20 and extra-long shaft engines will need a transom height of 25. Safely but briskly accelerate. See When St. Peters Basketball Games Are Today! (3) Move horizontally across the chart until you hit the graph curve. Engine Oil Mixing Ratio Fuel 50: Engine Oil 1. Here we will guide you in how to get the right boat transom height. Long shafts are 20-inches long. priceSelector: ".price--withoutTax, span.price.price--withTax", Mounting the motor lower on the boat transom can create excessive spray, increase case drag, reduce underwater clearance, and negatively impact faster boats. With such an important, long-term, and expensive upgrade, its never a bad idea to double-check. mpeSelector: ".pt-mpe", 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. Many boat transoms are modified to use a different length of outboard by using a bracket. Extra-extra long shafts are 30-inches long. If your outboard motor height. I would also recommend finding your maximum horsepower rating which is located on the yellow coast guard tag towards the back of your boat. s.setAttribute("src", script); 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. Most of the time, adding a hydrofoil to an outboard improves performance. Any questions? 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. Having the cavitation plate a bit lower than the transom is preferable to having it too high.