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Pushing a 27' Sailboat with Trolling Motor

15K views 26 replies 16 participants last post by  Zarathu 
#1 · (Edited)
I've got a 1980 15HP Evinrude motor on my Cat 27' that looks like it is going to be a bit of a project to fix up. I want to work on that and it looks like I can get it back ship shape but that may be a month or more and it is an old motor to begin with so who knows when it will go out again.

With that said I am interested in getting a little trolling motor to push me out of the marina into the lake so I can do some sailing while it is beautiful outside. Anyone have any experience pushing a 27 footer with a little trolling motor like this: http://www.amazon.com/Minn-Kota-Freshwater-Transom-Trolling/dp/B0043H31GG. I know the Cat is heavy so it will be slow going but pending the wind not being very strong anyone think this is manageable or just crazy talk? Think that a standard marine battery is up to running this trolling motor for ~30 minutes without discharging too much?
 
#2 ·
There are two or three boats (that I've noticed) around that size in our marina using trolling motors to get in and out of their slips. Pretty slow going, but it seems to work.

"Think that a standard marine battery is up to running this trolling motor for ~30 minutes without discharging too much?" -- Look up the specs of the motor you intend to use and of your battery. Divide the Ah rating of the battery by 2 and then divide that result by the max current draw of the motor (in amps). That will give you the hours (or fraction of hours) you can motor.
 
#9 ·
There are two or three boats (that I've noticed) around that size in our marina using trolling motors to get in and out of their slips. Pretty slow going, but it seems to work.

"Think that a standard marine battery is up to running this trolling motor for ~30 minutes without discharging too much?" -- Look up the specs of the motor you intend to use and of your battery. Divide the Ah rating of the battery by 2 and then divide that result by the max current draw of the motor (in amps). That will give you the hours (or fraction of hours) you can motor.
So the battery I am looking at (EverStart Marine Battery, Group Size 27DC - Walmart.com) has 110 Amp hours. And the motor draws 43 amps at full steam. So that gives me a little over an hour with your formula.

110Ah / 2 / 43A = 1.28 hours.

Can you tell me why I'm dividing by 2 here?
 
#3 ·
Last weekend we had a transmission failure (damper plate)... after sailing back home, to get back into our slip I tied our dinghy against the quarter and pushed our 11,000 lb 35 footer into the marina.. we got about 2 knots with our 3.5hp Nissan, may have gotten up to three but we never went 'flat out'.

I doubt we'd have made much progress against a headwind or a seaway, but in/out of the marina it worked.
 
#4 ·
Cabela's recommends 1 pound of thrust for every 40 pounds of boat weight.
Trolling Motor Buyer's Guide

Sailboatdata.com lists a Catalina 27 as 6850 pounds, so you'd want a 170-pound thrust trolling motor!

I use a 74-pound thrust Minn Kota motor on my Catalina 22. It's a 24-volt so I have two batteries in series. It pushes me at about 4 knots and I estimate I could run for an hour before the batteries were at 50%.

I think a 55-pound thrust motor would be awfully small for your boat. It would probably work if there was absolutely no wind, but if there was no wind what would you be doing out there?!
 
#6 ·
Depending on how much needs to be done to your current engine it may be easier to buy a used one.
Yeah... looking at costs I think you're probably right that that is the best path but I have some family coming in this week and really want it to be mobile for them... trying to decide the ideal path with that in mind.
 
#8 ·
My 9.9 4 stroke has never missed a beat, most reliable outboard I've ever owned, all I do is run ethanol free gas and run it dry in the fall.
I used to be a huge 2 stroke fan, not so much anymore, even my dirtbike is 4 stroke.
I don't think I'd ever go back to 2 stroke in anything but a chainsaw or lawn trimmer.
To each his own. Easy to get good ethanol free gas around here though, makes a difference.
 
#23 ·
True. The Ah rating for a deep-cycle battery is usually "20 hour" rating, or what the capacity would be if the current was scaled such that it takes 20 hours to drain the battery to its "minimum voltage" (10.5V, IIRC; which you never want to get anywhere near, unless you enjoy buying new batteries all the time). With the sort of currents a trolling motor is likely to draw you're probably looking at something like half to two-thirds of that. So, a conservative estimate would be to take the Ah rating and divide by 4 (2 for that higher draw, and 2 to keep the charge state above 50%) and THEN divide by the max current draw of your trolling motor.
 
#14 ·
I'd have to say Yamaha and Honda are the most common brands at my marina and seem to have few if any problems.
Last couple years there seems to be a big push to replace 2 strokes with 4. Think we only have a couple 2 strokes now.
My Yamaha has been great, I have electric start and console shift/throttle. Not much different than running an inboard. I'll be honest I don't think I'd own anything else Yamaha, don't care for their bikes since the end of the RD/RZ era.
I think the key to happy 4 stroke ownership is ethanol free gas, might be a bit anal but I also filter my fuel before it goes in the boat tank. Funnel with coffee filter....Been thinking about installing an outboard filter/separator.
Something like this, just the first one that popped up on google not suggesting this particular one.
Moeller 33328-10 Fuel Water Separator - Marine Outfitters - Ontario Canada.
I'm beginning to really think all the 4 stroke bashing is more due to owner than motor. Although not people fault if they can't get good gas.....gotta work with what you can get.
 
#15 ·
I own that exact trolling motor for my little jon boat along with a 3hp outboard. We just recently bought a 7.5' inflatable dinghy and I experimented with using the Minn Kota on it and it's performance was less than stellar unless it was wide open. I've decided to just use the gas outboard. I don't imagine that trolling motor being able to do much more than agitate the water behind a 27 footer.
 
#17 ·
Yeah, even on my old 16 foot sailboat i only got about 2.5 knots max out of the trolling motor and if there was any sort of wind it wasn't going anywhere. The biggest problem is going to be side winds. You won't have any kind of maneuvering power so will get blown sideways super easy. If there was no wind it will slowly move you around but then again its a sailboat so why would you be out at that point.

BTW, saw this on craigslist near you.

http://chattanooga.craigslist.org/boa/5592008045.html
 
#18 ·
I would focus on getting the Evinrude going. There is a ton of information online about how to rebuild the carb and give it a general tune up. That's all it takes to get most 2 strokes of that era going. My Dad inherited a 1960s era Evinrude 5 hp when I was a kid and still uses it today. They are pretty much bullet proof.
 
#21 ·
In a pinch I have used the Minn-kota to get in and out of our marina, (Lancer 36 apx 11,500 lbs.)
Once had to use it to go 2 miles in a flat sea. I would not expect it to do much of anything with a swell running, but for flat water it worked well. my .02 worth
Brad
Lancer 36
 
#22 ·
As I said in another post last fall... I have a walker bay RID with a 55 lb thrust Newport on it. My mooring is 950 feet from the dock. With a 10 knot wind against me and 1 foot seas, I had to run the Newport at flat out and in the 950 feet I drained about 30% out of a 75 AH gel battery to do about 1.5 knots. Unless I was running Wide Open, it wouldn't move.

On the way back to the dock, I used my Torqeedo 1003L. I chugged along at 3 knots in the same conditions in my 1200 lb +500 people & gear, West Wight Potter 19, pulling the dinghy too, and used maybe 2% of the battery.

Unless the sea is glass, I can't imagine how the trolling more would work for you very well.
 
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