sneaker

Well surfer has made some good points that are worth a little more effort on my part. You are right in that the motor will run longer at speed 2 than at speed 5 with either a CV or 5/3 speed control. Lets assume that speed 2 places 3 volts on the motor and 9 volts on the internal resistor. The motor voltage has dropped by x4 (compared to speed 5 it is 12/3) and so will the current drawn from the battery. So the motor will run 4 times longer on speed 2. But the resistor that was switched into the power lead will consume 3 times the power that the motor does since it drops 9 v and the motor only 3v. So the power from the battery is 12v x 3v/motor resistance (12x(V x I). On the CV motor, the controller converts the 12 v to 3 v with no power loss (rough estimate) and the battery power is now 3v x 3v/motor resistance . Thus in this example the CV motor can run 12v/3v = 4 times as long as the 5/3 motor when at speed 2. To be a bit more accurate we can assume a conversion loss of 10% in the CV converter so the improvement is only 3.7 times as long as the 5/3 at speed 2. MK makes the claim that the improvement is up to 5 times longer at some speeds, and I think they are right. The slowest speed will give the greatest improvement. You can tell the 5/3 T/Ms are permanent magnet (PM) motors with the following experiment. Disconnect the battery connections and set the speed to 5. Spin the prop with your hands and note that it spins freely. Now connect the 2 motor leads together, and spin the prop again. Takes a lot more effort?? That is because the motor is now operating as a generator and you have shorted the output, so it is working hard and you can feel it in the prop. CV motors have some electronics in the power leads and may not act the same since the drive circuit may not be active. So how about the 'bigger is better' approach? Like Surfer I have put a 26, 30, 40 and 50 lb motor on my boat. The 26 gave me a max speed of 3.8 mph, and all of the rest gave me 4.4 to 4.5 mph. In addition the battery draw was the same for the 30 to 50 lb motors. How come?? Most of you have noticed that if you pull a running T/M out of the water it does not 'rev up' like a gas motor would. That is because PM motors are constant rpm/volt motors. If you double the voltage on the motor it will double its rpm. It makes no difference if the motor is in the water or not. All of the above motors were measured and they turn 150 rpm per volt applied. So if you apply 10 volts the motor turns 1500 rpm. What has this got to do with max speed? M/K and perhaps MG have chosen to use props with 4 inches of pitch. Each revolution of the prop moves it 4 inches thru the water. With 12 V applied the motor turns 1800 rpm. So a perfect boat will move 1800 x 4 inches = 7200 inches or 600 ft per min or 6.8 mph. Most boats under 17 ft have a hull speed of 6.5 mph or less, and the 4 inch prop is a good match for them. So when I went from a 30 to 40 to 50 lb motor, all were spinning their prop at 1800 rpm, and had a pitch of 4 inches so all achieved the same max speed. And since all were doing the same ammount of work, all drew the same battery current. Except for the 26 lb motor. This motor could not draw 30 amps as it was designed to draw only 26amps at 12 v, so it was a bit slower. So it appears that the only way to get more speed out of a T/M is to find a prop with a higher pitch. Of course if you want to go faster the motor will draw more current, so the motor must be rated for the additional current. These 12v motors usually draw 1 amp per rated pound of thrust, so The 40 and 50 lb motors will safely turn a 7.5 inch prop and draw 40 amps (on my boat), when the 30 can not. Finding the right combination of pitch/ Diameter/ 2 or 3blades for your boat is a bunch of work and most fishermen are not that eager to get an additional 1 mph of max speed. But I have the time and so worked at for a while. So if your motor at max speed draws about 1 amp per rated lb of thrust, you have a good match for your boat. How can you tell? Borrow a digital VOM (volt-ohm-meter) or buy one at radio shack for 25 bucks. Put a 12 inch 10gau stranded piece of wire in the ground lead of your motor at the battery. Measure the voltage across the 12 inch wire(clip on to the wire, not the terminals). Your meter will indicate 1 millivolt for each amp of battery current. Now you are all set to play. Good luck.

If both boats have a transom, then a single motor can be used on either boat. The motor is secured with a couple of clamps and installs easily. Motor power is expressed as the amount of thrust (in lbs) the motor will provide when the boat is not moving. It provides some indication of how fast the motor will accelerate your boat from a stop. Most 12 volt motors will draw about 1 amp of battery current for each pound of thrust. A 24 volt motor will draw half as much, but you need 2 batterys. A small boat will not get much of an advantage going to 24 volts. The run time you get on a battery charge is determined by the Ampere Hour (AH) rating of the battery, and how much current the motor draws from it. A 75 AH battery will deliver 75 amps for 1 hour, 37 amps for 2 hrs and so on. I use a grp 24 battery that is rated at 75 AH. It will push my boat around a lake most of the day. Your battery will last much longer if you avoid discharging it more than 50% and you recharge it as soon as you get home. Use a marine deep discharge battery. Wallmart sells a grp 24 battery for about 50 bucks. Not all motors are going to provide the same effeciency. One 30 lb motor might run all day, and another only 3 hours. The difference is in the way they throttle the motor. The most effecient throttle is the continuously variable (CV) throttle. It converts the 12 volts to a lower voltage to operate the motor at less than full trottle and is 90% effecient. That is the motor gets 90% of the power at any selected speed and the controller uses 10% of the power making the voltage conversion. The OTHER method is the step throttle, usually 5 speeds forward and 3 in reverse. This design switches resistors into the power lead thus lowering the voltage available to the motor. At half speed 6 volts is applied to the motor and 6 volts is lost on the selected resisitor. Here the effeciency is 50%. At 1/4 speed 3 volts is applied to the motor and 9 volts lost across the selected resistor. Here the effeciency is 25%. So in the above examples, when operating at 25% power, the CV motor will run 3 1/2 times longer than the 5 speed motor. At full power they are about the same. Most of my time is spent as less than half throttle, so I use a CV motor. It more than doubles my run time on a charge. Either a 30 or 40 lb motor will drive your boat. They are inexpensive and offered by MinnKotta and Motor Guide. The bad news is MK offers only one 12 volt motor with a CV throttle, the 55 lb Vector or Vantage. The smaller motors are all 5/3 speed motors. I am fortunate enough to be able to design my own CV throttle for the MK40. You probably do not have that option. So for the equivalent performance a 30 or 40 lb 5/3 speed motor with an extra battery will run your boat all day.

Not knowing anything about that specific O/B, I think the folks that sold you the spring meant this. The springs usually break at either the starting loop in the spring, or at the end loop. These loops go over a post or thru a slot on the fixed (non-rotating) part of the motor, and the other end on the rotating part. It is very important that the replacement spring is wound in the same direction as the one that broke. If you get it backwards the new spring will break the first pull of the rope. With the spring installed, note the direction that the rope is wound on the starter hub. Once the new spring is in place pull a couple of feet of starter rope out, putting the spring under tension. Then wind the rope on to the hub while keeping the spring under tension so that the completed assembly holds the pull handle against the motor housing. This last step is a bit of a pain depending on the designed of the starter system. You may have to remove the handle from the rope to feed it thru the hardware and around the hub. Take your time and have fun...

The 2 blade props are more effecient than the 3. They are best for generating a lot of static thrust (that is thrust when the boat is not moving) and most motors come with one as it makes their specs look better. My MK 40 with a 2 blade prop generated 38 lbs of static thrust, but the 3 blade prop gave me only 28 lbs. But because I am using a light rig (about 300 lbs loaded) the 3 blade gave better speed, more effecient operation at slow speeds and far better handling in reverse. The 2 blades hooked up faster and provided steadier speed when I turned into the wind. So if you have a 1500 + lb bass boat, I think the 2 blade prop is the better prop for you. Both are pretty weedless.

The Endura 40 motor is the one I use all the time on my 12 footer. I think the 40 lb motor will push your boat along just fine. When operating at 1/2 throttle or less, the Maximizer series will more than double your operating time on the battery. But at WOT both speed control systems (maximizer and 5/3) draw the same battery current. So if you spend a lot of time at WOT go for the Endura. Wallmart sells them for about $165 on the west coast.

How did the motor respond to incremental speed increases? Did each step give you a little more power, even tho less than what was expected? When on WOT, was the speed as much as it used to be? If the WOT was less, then you probably need to have the motor brushes looked at. If the lower speed steps behaves differently, some OK some no increase, then one or more of the the resistors in the motor have failed, or the switch in the head has failed. Either way you may want ot find a friendly motor doctor. :-?

You didn't say if this is a new problem, and if the boat has operated well in the past. Assuming it is a new problem, two things come to mind. Cavitation of the prop at speed will feel like slipping as the prop couples to the water and then sucks air. Check the prop as see that is is not dinged on the leading edges, and the bottom of the boat is clean along the keel. The other thing it could be is a spun prop. The props have a rubber coupling (inside) between the shaft portion and the prop hub. If the rubber is getting marginal it will slip at high power levels, and get progressively worse. You will have to have a prop shop look at it, or just replace it. :-[

The motors with a continuously variable throttle (digital speed control/maximizer) will double your battery time when operating at 1/2 power or less. Thats where I spend most of my time. Not cheap, but neither is an extra battery set.

My B/L trophy has 2 pumps. The inlet pump is small, about 300 gals/hr, and the exhaust pump much larger, at least 600 gals/hr. Both pumps work together. The inlet pump brings outside water in and fills the tank at the bottom of the well, the exhaust pump gets its water from a hole located at the max water level of the tank and dumps it overboard. Hopefully the exhaust pump will always pump out enough water to keep the well from flooding. I do not run the pumps all the time, just enough to keep the water fresh.

The cone they are referring to is shape of the transducers sensitivity to returns from the bottom. An object in the cone will reflect more of the trasnmitted pulse and is represented on the screen. An object outside the cone will return a weaker signal and may not show on the screen at all. A 10 inch fish 10 feet down will reflect much more energy (ping) than the same fish 100 feet down. So it may be displayed as a larger fish. Smarter FFs can allow for the greater distance to the target and indicate about the same size fish for either the 10 ft target of the 100 ft target. You really don't care how they do this. Most FFS have 3 or 4 sizes of :-/ fish symbols for their display. A salmon and a whale would both be displayed as the largest size they have. :-/ Keep an eye on the FF, it is one of the most usefull tools you have on the boat.

You really can't paint anything in just one coat. If you get the paint on that heavy it will be full of runs. So just take your time and figure on 2-3 coats to get decent coverage. On the last coat pull the masking tape after the paint has been on long enough to be tack free, but not hard. The tape will part with the boat paint better and the boat paint will kind of roll over on the edge giving a nicer line.

I checked out Schumacher sc2500a. It sound roughly like the Vector vec1097A. The Vector charger has a far better description of the uinits features, but I don't know anyone that uses either one of these units. Both are 'high frequency' chargers. That is they convert the 120volt/60 Hz line power to 10-50Khz before the isolation transformer. This permits a very small transformer and a lighter charger unit. The vector is the less expensive of the 2. Both look like they are suitable for AGM batteries. The few reviews I can find on the vector complain of the chargers fan noise. I often have to charge 2 batts at a time and have decided to go with the vector unit. It offers 30 amps for the bulk charge (charging the battery to %75 of capacity) and then falls back to 5 or 10 amps to complete the job. I will just parallel the batts and do them together. My old 10 amp charger would not get the job done overnight. I figure I can replace the fan with a quieter one if the stock one is too loud. I will be using the charger for the 1st time over the July4th weekend. If I have a problem I will describe it on the forum.

Fishing out of a kayak is a ton of fun. I fish bass to salmon, and find steelhead to be the most challenging. It is a blast to get into a fish that you have to beach because it is too big to lift into the boat. I am using a boat from <kingfisherelectricboats.com>. Take a look and see if it is for you.

I have a homebuilt 10 ft kayak powered with a MK40 about the same weight as yours. The battery is a WM grp 24 deep cycle. This is a 75 amp Hour battery. That is it will deliver 75 amps for 1 hour, 25 amps for 3 hours and so on. My rig will go 3.5 mph using 15 amps of battery current. 4.2 if I assist with a paddle. Turning up the throttle to draw 30 amps gets me 4.6 mph with or without the paddle. Using those numbers you can see I will go about 75/30 x 4.6 = 11.5 miles at full throttle. But with half throttle and a paddle I can go 75/15 x 4.2 = 21 miles. So I seldom use full throttle on the boat, and if I am going a few miles I always paddle along with the motor at half throttle. The reason is the hull speed of our boats is only about 4.5 mph and it takes a very large increase in power as you approach hull speed or attempt to exceed it. So electric boats are like life, those who slow down and enjoy the trip will go much longer. I hope you have as much fun as I do in your new rig...

I recommend you get rid of that trickle charger first. The 'smart chargers' manufactured in the last 6 years start charging the battery at 20-30 amps until the battery is 75% charged, and then fall back to 2-6 amps for the rest of the charge cycle. The battery is charged in about 10 hours. A trickle charger delivering 1-2 amps will require 4-5 days to charge a single 100 A/H battery. If you have a 24 volt motor, double the time. As you can see, you may never get the battery fully charged, and operating the system with partially charged batterys will shorten the battery life. In the above scenario (2 batterys) the second battery sits around dishcharged for a week before it gets started on the charger, hardening the sulfate coating on its plates and deteriorating the capacity of the battery. Any charger you get should completely charge a battery in 24 hours. So a charge current of at least 5 amps is required. I would go for 10 amps minimum. Good luck

The battery switch will easily handle the TM current. But removing the TM from the boat may be a little more of a problem without the quick disconnect connector.

If the marine battery is a deep discharge or deep cycle battery, leave it on the TM. This motor will draw a moderate amount of power all day long, and standard batterys do not do that very well. The 6 volt Batts are probably cranking batterys and should be used for starting the motor. A cranking battery is designed to deliver a lot of current for a short period of time, and then be recharged by the alternator. Deep discharge batterys are always (?) labeled as such. If it doesn't say DD, then it is a cranking battery.

JH-Sorry for the somewhat confusing answer. I wanted to answer Moses question also and made it less clear for both of you. In 2004 MK published the volt/amp draw specs for all of their motors. Your 36v/101lb motor has a max draw of 37 amps. One of the limitations of these motors is the size and durability of the brushes, which are in the current path thru the armature of the motor which the propeller is bolted to. The maximum current specified for any MK motor is 45 amps. That is probably all the brushes can handle and have a reasonable operating life.

Your 36V or 24V motors will draw less than 40 amps at full throttle . The 20 ft boat will have 40 ft of wiring and it will drop 1.6 volts across all of the wiring at 40 amps. The 6 inch section will not make a significant difference if it is 6 gua or 10 gua. The boat with 6-8 gua has plenty of capacity for the motor he is using. Be carefull when you get to the connectors. A loose connection here can cause a lot of heat and the melting of the connector. Make sure they are clean and I prefer to solder the wire to the connector if the connector allows. Some use screw clamps but can still be soldered if you are concerned about a screw working loose with all of the thermal cycling.

The newer 'Smart Battery Chargers' will charge the battery at 30-40 amps until the batt comes up to State of Charge (soc) of %75. They call this a bulk charge and it is determined by the voltage across the battery terminals. They then fall back to a 2-5 amp charge rate for the remainder of the charge cycle. Their claim is that the lower final charge rate allows the battery to accept a greater final charge level than the higher amperage would permit. They will also dump up to 80 amps into a completely dishcarged battery for 5 mins to permit a vehicle to be started. So apparently the current isn't an issue until the battery reaches a 75% soc. My antique charger charges at a 10 amp rate until the battery is fully charged and then falls back to a trickle charge until it is turned off. So the short answer is go ahead and charge at 10 or 15 amps, and if you want maximum energy in the battery, drop back to 2-5 amps for the last few hours of charging. Incidentally a company called Firefly Energies has developed a carbon/lead battery with 2-3 times the energy storage capacity of the best lead/acid batterys now available. They claim their test folks have charged it a 300 amp rate to full charge. They also claim it will provide 800 discharge/charge cycles with no significant loss of capacity. Both of those numbers are at least 3 times better than todays lead/acid batterys. These batterys are compatible with todays manufacturing processes, and therefor should be comparably priced. They plan to be in production this fall.

Well Brian we don't have much information to work with. What year is the motor, 2 stroke or 4 stroke, carburated or EFI? Have you used the boat in the 60 day period since it was in the shop.? Did it run well then? Is the boat stored outside? Why did you only run it for 10 sec? Was the motor out of the water? Did you have 'ear muffs on it to provide coolant to the engine and lubricate the water pump impeller? If in the water ,was cooling water visible in the exhaust port? In 10 secs the motor is still cold and if a 2 stroke it has little lubrication in the power head. Crankshaft seals are dry, pistons don't seal well and it might not idle at all. Be sure coolant is flowing thru the engine and run it as slow as it will keep running until it warms up. Then check for proper idling.

The picture on the screen is a history of what your boat has passed over. On the right is the bottom data of your present location, on the left is the bottom data taken earlier. The scroll speed (how fast the picture is written) can be adjusted so that it takes a 60 secs to complete the pic. Then the data on the left is what the bottom looked like one min ago. In the picture you provided the boat passed from shallow to deeper water. Most FFs will draw a pic of a fish (fish ID option) if you passed over a fish. Some will write the depth of the fish next to the image. The side looking FFs will tell you if the fish was left or right of the boat when you passed over it. The bottom texture is indicated by the width of the bottom displayed. In the example you provided the bottom is soft with a hard layer deeper down. If you were over a hard bottom the bottom displayed would be shown as a thinner line. Weeds look like a soft bottom, but will usually vary in depth with a harder bottomline below . When your boat passed from deep to shallow water, and then back to deep again, you will see a mound on the screen. This is important botom structure information that you want to pay attention to. Fish will often hold, or hang out on this kind of bottom depth change, and you will want to fish that structure. With experience you will find the FF is one of the most valuable tools you have on the boat. Play with it and learn what things are usefull. For example the gain (or sensitivity ) will have a big effect on its ability to show fish. Too much gain and it will show fish everywhere, too little and their will be NO fish. Fiddle with it and you will learn what is real and what is junk. Good luck...

yeah. Better choice I think. You get more of what you need for less money..

Shumacher makes a long series of chargers and they are (in my opinion) pretty good chargers. I prefer one with an amp meter on the panel as it indicates bow well the battery is accepting a charge. Voltmeters, % of charge meters and LEDs do not provide that information. Over time you will notice what the 'normal charge sequence' is and as your batterys age, or if you charge a battery for a friend, you will know that to expect. Perhaps the 12 amp charge rate will make a difference, but when charging overnight, it will not be noticed. Schumacher also has a charger that will give a 30 amp 'Boost charge'. This could be usefull if you are in a hurry, like you forgot to put the batt on the charger last night. It sells for 60 bucks. After a couple of hours on the 30 amp setting, switch to the normal charge setting to complete the charge process. I would like to see a charger that is about 1/4 the size of todays chargers, one that is truley transportable. It should be possible to make a 10-25 amp 12v charger with all of the characteristics of the Shumacker chargers, and I would be glad to spend another 25 bucks to get one. Having designed several Off-Line swithching supplies, it seems like a task these guys could get done. Shucks I wouldn't care if they had a small fan in it.

I used to have one of those. Powered it with a merc mk20 after adding a stout brace to the boats transom. Kept up with the skiers with a couple of kids on board. Just sand the old paint off but be carefull not to go past the paint and into the f/g. You can buy some epoxy marine bottom paint and get a nice finish on it. Or if you don't have a marine store handy, I have used epoxy appliance paint with good results. It is in a spray can and sells for about 6.50. It will take at least 5 cans to give adequate coverage on a 12 ft boat. So it is about the same price as a pint of epoxy marine paint. I think the flotation for that boat was some foam in the seats. They were an important structural part of the boat so when you deck it, l recommend you leave the seats in. That will place the deck pretty high, like most bass boats, and it might be a little tippy. If you are planning to fish 2 off the boat, be sure you are good friends. Those trebble hooks go by pretty fast.