I just bought an ODay 22 fix keel, it weights 2,000 pounds. The gas motor it came with is not reliable. I just need the motor to get me in an out of the Harbor or Marina. What type of electric motor is out their that has enough power to get me in and out of the Harbor?
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Dan McGuire
Order of Magnitude Estimate
I have a MAC 23 with a swing keel which weighs about 2000 pounds. I use a 30 pound thrust trolling motor as a backup. It pushes me at about three knots fully charged and uses about 30A at 12V. You need to determine how fast you want to be pushed. As a rule of thumb, the speed goes up as a square root of the thrust up to near hull speed. For example if you think you need to go 5 knots then you need about (5knots/3 knotts) squared times 30 pounds or about 83 pounds of thrust. The amount of power required goes up roughly proportional to the thrust. Therefore at 83 pounds of thrust you need about 83A of current. Actually the larger motors are more efficient and probably only about 75A at 12V is required. Before everyone gets bent out of shape about this, these are rough estimates and will be enfluenced by many factors such as the prop.
I have a MAC 23 with a swing keel which weighs about 2000 pounds. I use a 30 pound thrust trolling motor as a backup. It pushes me at about three knots fully charged and uses about 30A at 12V. You need to determine how fast you want to be pushed. As a rule of thumb, the speed goes up as a square root of the thrust up to near hull speed. For example if you think you need to go 5 knots then you need about (5knots/3 knotts) squared times 30 pounds or about 83 pounds of thrust. The amount of power required goes up roughly proportional to the thrust. Therefore at 83 pounds of thrust you need about 83A of current. Actually the larger motors are more efficient and probably only about 75A at 12V is required. Before everyone gets bent out of shape about this, these are rough estimates and will be enfluenced by many factors such as the prop.
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IKE ENRIQUEZ
Electric Motor
Dan, Thanks for your input. I was considering a 30 TO 40pound trust I was just not sure if it could move the boat. I will only need to move 1.5 tp 3 knots to get in & out of the Harbor. Actually going back in, the slower the better.
Dan, Thanks for your input. I was considering a 30 TO 40pound trust I was just not sure if it could move the boat. I will only need to move 1.5 tp 3 knots to get in & out of the Harbor. Actually going back in, the slower the better.
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Ted
If you are on the ocean. . .
an electric motor will not serve you well with waves and current. A smaller gas engine would be preferable. If you are on a lake, then you should be OK. Regards, Ted
an electric motor will not serve you well with waves and current. A smaller gas engine would be preferable. If you are on a lake, then you should be OK. Regards, Ted
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Gerry
Motor
An electric motor will not work well if you are going to use it in any conditions other than pristine. In order to have any long term use you will have to have quite a large battery bank to support the engine use. You can find a used 2 or 4 stroke outboard pretty cheap on the internet. The only lake it would be ok on would be a small inland lake. I sail the great lakes and don't recommend going out there with just an electric motor. Fair winds Gerry
An electric motor will not work well if you are going to use it in any conditions other than pristine. In order to have any long term use you will have to have quite a large battery bank to support the engine use. You can find a used 2 or 4 stroke outboard pretty cheap on the internet. The only lake it would be ok on would be a small inland lake. I sail the great lakes and don't recommend going out there with just an electric motor. Fair winds Gerry
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Dan McGuire
Agree Somewhat
A small electric or trolling motor will only work well under ideal conditions. I only use it as a backup. (See my previous posting). Under high winds, i.e. 15k or greater it is very difficult to handle. I don't have a noticeable current. You pay a high penalty for trying to go faster with a larger motor because of the current drain. You can calculate, roughly, how long your battery will last. Look at the AH rating for the battery. The larger 12V marine batteries are 100AH or more. In the example I gave, you could run for about an hour or so at 5k. If that is adequate, you are in business. It is fun to motor into the marina under electric power. The other sailors are not quite sure what to think.
A small electric or trolling motor will only work well under ideal conditions. I only use it as a backup. (See my previous posting). Under high winds, i.e. 15k or greater it is very difficult to handle. I don't have a noticeable current. You pay a high penalty for trying to go faster with a larger motor because of the current drain. You can calculate, roughly, how long your battery will last. Look at the AH rating for the battery. The larger 12V marine batteries are 100AH or more. In the example I gave, you could run for about an hour or so at 5k. If that is adequate, you are in business. It is fun to motor into the marina under electric power. The other sailors are not quite sure what to think.
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Chris
A little more is better
Make sure you're allowing youself enough power. You'll need the motor for more than just putzing back in. Motors are great for getting out of the way of other craft (esp big ones) and for getting out of bad weather (everyone gets caught eventually). Why not condsider a 3-4 hp gas motor? It'll probably end of being lighter than all the battery weight you'll need to carry. Chris
Make sure you're allowing youself enough power. You'll need the motor for more than just putzing back in. Motors are great for getting out of the way of other craft (esp big ones) and for getting out of bad weather (everyone gets caught eventually). Why not condsider a 3-4 hp gas motor? It'll probably end of being lighter than all the battery weight you'll need to carry. Chris
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Bob
Some years ago
I had just bought an 18 foot cuddy cabin sailboat and had the same question - figured all I needed the motor for was to ease out far enough to raise the sails. But, really, it is much more important for getting back in than it is for getting out. It is real frustrating to be far from the marina when the wind dies and not able to sail back, or to have to limit where you go to the amount of juice in the battery. And on a real windy day it is a bear to bring the boat in or load it on a trailer without the motor. Luckily, I ran across a nice 3hp Yamaha in good shape that same week, and it was the best $300 I ever spent - especially since it was worth the same amount 6 years later when I sold the boat.
I had just bought an 18 foot cuddy cabin sailboat and had the same question - figured all I needed the motor for was to ease out far enough to raise the sails. But, really, it is much more important for getting back in than it is for getting out. It is real frustrating to be far from the marina when the wind dies and not able to sail back, or to have to limit where you go to the amount of juice in the battery. And on a real windy day it is a bear to bring the boat in or load it on a trailer without the motor. Luckily, I ran across a nice 3hp Yamaha in good shape that same week, and it was the best $300 I ever spent - especially since it was worth the same amount 6 years later when I sold the boat.
Gas AND electric motor
My Mac 26D came with a 2 stroke 9.9 HP gas motor and it does fine for moving the boat quickly but I had problems when bringing the boat back into the harbor because when I would throttle the engine down to just above an idle I was still going faster than I really wanted (the harbor is small and really tight) and the engine would 'load up' and stall about half the time and be really hard to restart. All this while I'm trying not to run into other boats! Sooo, I installed a MinnKota Endura 55 next to the outboard that is used for that final few hundred yards and it works great. At full power it will push the boat along at around 2.5k but at low power it will just barely crawl and that makes it a lot easier to put the boat right where I want it. Another benefit is when I want to move the boat a short distance at night and don't want to wake the neighbors in a quiet anchorage. IMHO, having both gas and electric propulsion is the only way to go!
My Mac 26D came with a 2 stroke 9.9 HP gas motor and it does fine for moving the boat quickly but I had problems when bringing the boat back into the harbor because when I would throttle the engine down to just above an idle I was still going faster than I really wanted (the harbor is small and really tight) and the engine would 'load up' and stall about half the time and be really hard to restart. All this while I'm trying not to run into other boats! Sooo, I installed a MinnKota Endura 55 next to the outboard that is used for that final few hundred yards and it works great. At full power it will push the boat along at around 2.5k but at low power it will just barely crawl and that makes it a lot easier to put the boat right where I want it. Another benefit is when I want to move the boat a short distance at night and don't want to wake the neighbors in a quiet anchorage. IMHO, having both gas and electric propulsion is the only way to go!
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