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Author Topic:   DAUNTLESS 15 Re-power

mpbspb posted 07-20-2009 10:58 AM ET (US)
I currently have a 1992 [Evinrude] 60 on my DAUNTLESS 15. I am considering a re-power and need some advice. I do a lot of trolling. I installed a [Minn Kota] engine mount trolling motor, which does fine trolling, but it really creates too much drag when on plane. My top end now is about 29-MPH. I would like to eliminate the trolling motor, as [I] am convinced this is not a good set up. Would a four-cycle engine be better for trolling ad 1.5-MPH Would [I] still need a trolling plate? How would the top end performance be compared to my current engine? What horsepower would you recomend [in a four-cycle engine for a DAUNTLESS 15]?
mpbspb posted 07-25-2009 08:40 PM ET (US)
Anyone?
bloller posted 07-25-2009 09:29 PM ET (US)
29mph seems pretty slow. I think the max for that hull is 75hp. I think it will do over 40 with the 75hp. You might not be set up with the right engine height or prop.
If you do a lot of trolling then you should go with a Etec or 4 stroke for better fuel economy and quiet running. I would get a 60 Etec or 60 Yamaha or Mercury 4 stroke. The 75hp Etec and Yamaha Mercury 4 strokes are quite a bit more money and weight.
Dauntless_14_TX posted 07-30-2009 10:51 AM ET (US)
29mph does seem really low. I'd go with a new 60HP EFI four stroke. IF you get the smartcraft guage you can actually dial down your idle speed for trolling thus eliminating the need for a trolling plate. The new engines are heavier so staying with a 60 4-stroke would be like having a 75 2 stroke on the back. Plus the 60 will troll a lot better than the higher HP in newer models. I have a 1999 Dauntless 14 that I just repowered with a 60HP EFI 4 stroke and at wide open throttle with a 13" pitch Vengenace prop can do 36mph and around 26mph cruise. Hope this helps some.
Tom W Clark posted 07-30-2009 11:09 AM ET (US)
Please explain why the trolling motor is creating ANY drag. It might add a small amount of weight but it's not in the water unless you are trolling so it cannot add drag.
A Whaler factory performance report I have for the Dauntless 15 shows that with a two stroke Mercury 60 (not known as a strong motor) indicates the boat would do over 39 MPH with the note that it was loaded "Heavy" during that test.
mpbspb posted 07-30-2009 01:09 PM ET (US)
It is an engine mounted trolling motor. Mounts on top of cavitation plate. When up on plane it is supposed to be out of the water.
Tom W Clark posted 07-30-2009 01:18 PM ET (US)
Yes, so if it's out of the water, it is not adding drag.
There has to be something else terribly wrong.
The same performance report show the Dauntless 15 powered by a 30 HP Yamaha two stoke being able to hit 31 MPH.
Tohsgib posted 07-30-2009 02:26 PM ET (US)
Honestly those trolling motors are pretty cool. I would use it on your next engine...after you try it without of course. Make sure that engine is up on the 2nd to last hole. If you do decide to nix it, let me know what you want for it.
mpbspb posted 07-31-2009 08:03 AM ET (US)
I love the trolling motor. It works great for trolling. The only problem is the drag created when running on plane. I adjusted the height of the outboard with no success. The boat does not ride high enough out of the water to get the trolling motor above the water line like it was designed to do. I only get about 28mph when before I was at 35 @ wot. I will let you know if I get rid of the trolling motor.
Tom W Clark posted 07-31-2009 04:10 PM ET (US)
I still do not understand how the trolling motors adds drag.
A cavitation plate mounted trolling motor is mounted above the cavitation plate.
When an outboard powered boat is on plane the cavitation plate is at or above the surface of the water so the trolling motor is free and clear of the water. Where does the added drag come from?
There is some piece of the puzzle missing. You do not happen to have an extra long (25") shaft motor on your Dauntless 15?
Do you have a photo that shows the trolling motor mounted on your motor?
fishgutz posted 07-31-2009 04:12 PM ET (US)
I think Tom is on to something.
Show us a picture.
Tom W Clark posted 07-31-2009 04:16 PM ET (US)
The upper right hand photo here shows how an engine mounted electric trolling motor looks at speed:
http://www.minnkotamotors.com/products/trolling_motors.aspx?subcat=6
fishgutz posted 07-31-2009 04:34 PM ET (US)
Now mpbspb need to show us a picture of the back of the boat. It doesn't even have to be in the water.
mpbspb posted 08-01-2009 07:31 PM ET (US)
Here you go. Hope the pics help. Let me know if you need more detail. Thanks for the help!

http://picasaweb.google.com/mpbspb71/MinnKota?authkey=Gv1sRgCOq58Mnj54TS_QE&feat=directlink
Tom W Clark posted 08-01-2009 09:49 PM ET (US)
Yes, just as I thought. The trolling motor is not contributing any drag. That 60 HP motor is a 20" shaft and it is mounted two holes up, which is good.
I believe it is a coincidence that you speed dropped after the trolling motor was installed. I believe the loss of speed is due to your motor running on only two cylinders.
If formerly your boat went 35 MPH with 60 HP, we would expect it to go only 28.6 MPH with only 40 HP according to the Crouch Calculator.
The close correlation between the observed speed difference and the calculated speed difference is no coincidence.
Check for spark on all three cylinders.
mpbspb posted 08-01-2009 10:00 PM ET (US)
I will check spark. Should the cavitation plate run at water level when on plane? Is it possible that the added weight of the trolling motor on an already weight sensitive boat have affected the dynamics to create this problem. I talked to minn kota and they said the trolling motor will not work with some set ups.
number9 posted 08-02-2009 10:25 AM ET (US)
To me the motor appears to be mounted too low and there's a lot of mounting hardware that may causing some drag. Are the nuts on the bottom side as it appears? If so you try should reversing the mounting hardware.
Tom W Clark posted 08-02-2009 12:14 PM ET (US)
The cavitation plate should be just above the surface of the water when the boat is on plane.
Even if the cavitation plate were on the surface and some little bits of hardware were dragging, it is not going to make a noticeable difference in the speed of the boat let alone a 25 percent reduction is speed.
Yes, the weight of the trolling motor *could* affect the dynamics to some degree. The most likely change you might notice is a greater propensity to porpoise with the center of gravity moved back a wee bit. But again, there is now way this could account for any gross reduction in boat speed.
Bill B posted 08-04-2009 10:45 PM ET (US)
I just sold a 1998 Dauntless 15 with a 75 Mercury two stroke, which I had since new. With the stock alum prop, 15 gallons of fuel, optima battery, anchor, cooler with diet coke in it and two good sized adults, the boat topped out at 53mph on the Ray Marine paddle wheel sensor and very close to that on the GPS. Very fast, very quick to accelerate. With the added weight of that motor, the port and starboard scuppers did let water back in the boat when I stood in the back. Cure, bathtub plugs installed in the inside of the scupper when fishing / trolling, not when running as the self bailing feature can come in handy.
Any four stroke is going to add considerable weight. Yes that boat was rated for 75 HP max. in 1997 and 75 in 1998, min hp was 30. Boat weight without motor was 730 lbs. Recomended engine shaft length 20" Max weight capacity in pounds 3 people, motor and gear was 1300. For a comparision, a new 2007 Mercury 75 Optimax DI 2 stroke weighs 375 Lbs. the same new Mercury 75 EFI 4 stroke 399 lbs.
As with any Whaler put as much HP on the boat taking into consideration the weight of the motor and coast guard ratings, that you can. Perhaps your boat is telling you to drop kick the Evinrude and go with Mercury.
Just my view
mpbspb posted 08-05-2009 09:49 AM ET (US)
What would you guess my 92 60hp evinrude weighs?
Tom W Clark posted 08-05-2009 10:50 AM ET (US)
248 pounds.

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Author	Topic: DAUNTLESS 15 Re-power
mpbspb	posted 07-20-2009 10:58 AM ET (US) I currently have a 1992 [Evinrude] 60 on my DAUNTLESS 15. I am considering a re-power and need some advice. I do a lot of trolling. I installed a [Minn Kota] engine mount trolling motor, which does fine trolling, but it really creates too much drag when on plane. My top end now is about 29-MPH. I would like to eliminate the trolling motor, as [I] am convinced this is not a good set up. Would a four-cycle engine be better for trolling ad 1.5-MPH Would [I] still need a trolling plate? How would the top end performance be compared to my current engine? What horsepower would you recomend [in a four-cycle engine for a DAUNTLESS 15]?
mpbspb	posted 07-25-2009 08:40 PM ET (US) Anyone?
bloller	posted 07-25-2009 09:29 PM ET (US) 29mph seems pretty slow. I think the max for that hull is 75hp. I think it will do over 40 with the 75hp. You might not be set up with the right engine height or prop. If you do a lot of trolling then you should go with a Etec or 4 stroke for better fuel economy and quiet running. I would get a 60 Etec or 60 Yamaha or Mercury 4 stroke. The 75hp Etec and Yamaha Mercury 4 strokes are quite a bit more money and weight.
Dauntless_14_TX	posted 07-30-2009 10:51 AM ET (US) 29mph does seem really low. I'd go with a new 60HP EFI four stroke. IF you get the smartcraft guage you can actually dial down your idle speed for trolling thus eliminating the need for a trolling plate. The new engines are heavier so staying with a 60 4-stroke would be like having a 75 2 stroke on the back. Plus the 60 will troll a lot better than the higher HP in newer models. I have a 1999 Dauntless 14 that I just repowered with a 60HP EFI 4 stroke and at wide open throttle with a 13" pitch Vengenace prop can do 36mph and around 26mph cruise. Hope this helps some.
Tom W Clark	posted 07-30-2009 11:09 AM ET (US) Please explain why the trolling motor is creating ANY drag. It might add a small amount of weight but it's not in the water unless you are trolling so it cannot add drag. A Whaler factory performance report I have for the Dauntless 15 shows that with a two stroke Mercury 60 (not known as a strong motor) indicates the boat would do over 39 MPH with the note that it was loaded "Heavy" during that test.
mpbspb	posted 07-30-2009 01:09 PM ET (US) It is an engine mounted trolling motor. Mounts on top of cavitation plate. When up on plane it is supposed to be out of the water.
Tom W Clark	posted 07-30-2009 01:18 PM ET (US) Yes, so if it's out of the water, it is not adding drag. There has to be something else terribly wrong. The same performance report show the Dauntless 15 powered by a 30 HP Yamaha two stoke being able to hit 31 MPH.
Tohsgib	posted 07-30-2009 02:26 PM ET (US) Honestly those trolling motors are pretty cool. I would use it on your next engine...after you try it without of course. Make sure that engine is up on the 2nd to last hole. If you do decide to nix it, let me know what you want for it.
mpbspb	posted 07-31-2009 08:03 AM ET (US) I love the trolling motor. It works great for trolling. The only problem is the drag created when running on plane. I adjusted the height of the outboard with no success. The boat does not ride high enough out of the water to get the trolling motor above the water line like it was designed to do. I only get about 28mph when before I was at 35 @ wot. I will let you know if I get rid of the trolling motor.
Tom W Clark	posted 07-31-2009 04:10 PM ET (US) I still do not understand how the trolling motors adds drag. A cavitation plate mounted trolling motor is mounted above the cavitation plate. When an outboard powered boat is on plane the cavitation plate is at or above the surface of the water so the trolling motor is free and clear of the water. Where does the added drag come from? There is some piece of the puzzle missing. You do not happen to have an extra long (25") shaft motor on your Dauntless 15? Do you have a photo that shows the trolling motor mounted on your motor?
fishgutz	posted 07-31-2009 04:12 PM ET (US) I think Tom is on to something. Show us a picture.
Tom W Clark	posted 07-31-2009 04:16 PM ET (US) The upper right hand photo here shows how an engine mounted electric trolling motor looks at speed: http://www.minnkotamotors.com/products/trolling_motors.aspx?subcat=6
fishgutz	posted 07-31-2009 04:34 PM ET (US) Now mpbspb need to show us a picture of the back of the boat. It doesn't even have to be in the water.
mpbspb	posted 08-01-2009 07:31 PM ET (US) Here you go. Hope the pics help. Let me know if you need more detail. Thanks for the help! http://picasaweb.google.com/mpbspb71/MinnKota?authkey=Gv1sRgCOq58Mnj54TS_QE&feat=directlink
Tom W Clark	posted 08-01-2009 09:49 PM ET (US) Yes, just as I thought. The trolling motor is not contributing any drag. That 60 HP motor is a 20" shaft and it is mounted two holes up, which is good. I believe it is a coincidence that you speed dropped after the trolling motor was installed. I believe the loss of speed is due to your motor running on only two cylinders. If formerly your boat went 35 MPH with 60 HP, we would expect it to go only 28.6 MPH with only 40 HP according to the Crouch Calculator. The close correlation between the observed speed difference and the calculated speed difference is no coincidence. Check for spark on all three cylinders.
mpbspb	posted 08-01-2009 10:00 PM ET (US) I will check spark. Should the cavitation plate run at water level when on plane? Is it possible that the added weight of the trolling motor on an already weight sensitive boat have affected the dynamics to create this problem. I talked to minn kota and they said the trolling motor will not work with some set ups.
number9	posted 08-02-2009 10:25 AM ET (US) To me the motor appears to be mounted too low and there's a lot of mounting hardware that may causing some drag. Are the nuts on the bottom side as it appears? If so you try should reversing the mounting hardware.
Tom W Clark	posted 08-02-2009 12:14 PM ET (US) The cavitation plate should be just above the surface of the water when the boat is on plane. Even if the cavitation plate were on the surface and some little bits of hardware were dragging, it is not going to make a noticeable difference in the speed of the boat let alone a 25 percent reduction is speed. Yes, the weight of the trolling motor could affect the dynamics to some degree. The most likely change you might notice is a greater propensity to porpoise with the center of gravity moved back a wee bit. But again, there is now way this could account for any gross reduction in boat speed.
Bill B	posted 08-04-2009 10:45 PM ET (US) I just sold a 1998 Dauntless 15 with a 75 Mercury two stroke, which I had since new. With the stock alum prop, 15 gallons of fuel, optima battery, anchor, cooler with diet coke in it and two good sized adults, the boat topped out at 53mph on the Ray Marine paddle wheel sensor and very close to that on the GPS. Very fast, very quick to accelerate. With the added weight of that motor, the port and starboard scuppers did let water back in the boat when I stood in the back. Cure, bathtub plugs installed in the inside of the scupper when fishing / trolling, not when running as the self bailing feature can come in handy. Any four stroke is going to add considerable weight. Yes that boat was rated for 75 HP max. in 1997 and 75 in 1998, min hp was 30. Boat weight without motor was 730 lbs. Recomended engine shaft length 20" Max weight capacity in pounds 3 people, motor and gear was 1300. For a comparision, a new 2007 Mercury 75 Optimax DI 2 stroke weighs 375 Lbs. the same new Mercury 75 EFI 4 stroke 399 lbs. As with any Whaler put as much HP on the boat taking into consideration the weight of the motor and coast guard ratings, that you can. Perhaps your boat is telling you to drop kick the Evinrude and go with Mercury. Just my view
mpbspb	posted 08-05-2009 09:49 AM ET (US) What would you guess my 92 60hp evinrude weighs?
Tom W Clark	posted 08-05-2009 10:50 AM ET (US) 248 pounds.