krypton1
12.05.2021 20:24:00
Having the cavitation plate too low will cause excess drag and reduced performance at high speeds. For slower boats, it’s less critical to more
See full version: How to Measure Your Outboard Motor Shaft Length
Having the cavitation plate too low will cause excess drag and reduced performance at high speeds. For slower boats, it’s less critical to more
Many boat transoms are modified to use a different length of outboard by using a bracket. Offshore vessels are often equipped with a large mounting bracket so that the transom can be left at full height. This provides seaworthiness and offers maximum protection from large seas. These allow the mounting of a standard length outboard behind the transom. more
Beefier jack plates can be fitted should a boater be looking to mount an outboard with a shorter shaft than their transom demands. They’re also useful if the back of your boat has a non-standard measurement. With a jack plate, you can mount it exactly where you want it. more
There are also specialty motor shaft lengths. Small motors built for sailboats might come in a unique configuration with an extremely long shaft since these are mounted higher off the water. The same is true for the newest, high-powered offshore fishing boats, where triple or quadruple motor setups are becoming more and more common.
Re: Long shaft on a short shaft transom. problem or no? [links]
Re: Long shaft on a short shaft transom. problem or no?
client damages it. i f you are renting, i highly recommend using the jack plate, as someone may say the boat had the wrong set up, using the long shaft. this could be a liability problem in and accident. [links]
There is nothing wrong with the old Johnson. I just needed a second motor as a back-up in case it goes out of service for a period if a client damages it. I had hoped to find another short shaft but couldn't and came up with the Merc for a good price ($380).
I'll post a pic of the boat and the Johnson but I don't have a pic yet of the Merc long shaft. here
Re: Long shaft on a short shaft transom. problem or no?
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. I would ask you to go back and measure the transom of your boat. I mean it is better to be safe than sorry, am I right? The transom is the back of the boat where the motor is hung. To do so, you will want to measure at the exact center of the transom from the very top to the very bottom. If it measures 15" or with in a inch of that you will need a short shaft outboard. If it measures anywhere from 17" to around 22", then your going to want to go with a long shaft motor. Anything bigger than that your obviously going to need an extra long shaft. here
The dealer just hit you with the long or short shaft question and you have no clue as to what you need or even what he's talking about. You reply, "Im not sure, I think its a 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. So from there, I will try to help out by asking questions about your boat such as what type it is and the length. With some boats I have a pretty good idea as to what length motor should be hung on them. 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. If you said something smaller than that, thats where it can get tricky. Smaller 12-14 foot boats can require either a short or long shaft outboard depending on the style of the boat and the brand. here
Your at your local outboard dealer shopping for a new motor and the salesman hits you with the question, "short or long shaft?". For most boaters this is a no brainer, but for the novice or inexperienced boater it may be a tougher question. 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. I mean, who wants to purchase something as expensive as an outboard to only realize you bought the wrong one. 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.
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. This placement is not only recommended but it will give you the best performance compared to something that is too long or too short. If you went too long it would still work but it may lack in performance. You will also risk hitting bottom or submerge objects more frequently such as rocks or logs. If you go too short your more than likely going to cavitate and loose power. 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. This is probably the worst case scenario out of the two. At least if its too long you can raise the motor or "build up" your transom.
Thats it. Pretty easy to figure out but like I said its crucial to pairing a motor with a boat. I would also recommend finding your maximum horsepower rating which is located on the yellow coast guard tag towards the back of your boat. 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. Using your existing control box and gauges will save you quite a bit of money in the end. I hope this helps someone out in their search for a new or newer outboard this season. here
A good rule of thumb when determining how much thrust you need for you pontoon is to take the weight of your boat in pounds and divide it by 100 . Then, take that result and times it by two.
Additionally, if you already have a fish finder installed in your pontoon, check and see if that manufacturer makes trolling motors. Many companies make both, and they design them to optimally work together.
Here’s a piece of advice for determining how long your shaft should be. Go to where you plan on mounting your trolling motor and measure the distance from your mounting point to the water. Take that distance and add 20” to it (approximately 51cm). more
Generally speaking, the average shaft length for a trolling motor is around 60”, or 152cm, if you intend on mounting the motor on the bow of your boat. While this is a good rule of thumb, there are other things to consider when determining this length.
Don’t underestimate how important power is when choosing a trolling motor. Most anglers regret buying a weak motor that can barely move their pontoon. Avoid this by making sure that you get a motor with enough thrust to carry you.
If this is your first time buying a trolling motor, I’d recommend that you don’t cut any corners and settle for a subpar motor. A cheap trolling motor will either be too weak or noisy, and it will almost certainly be working against you throughout your fishing trip.