Hello,

 

I am currently refinishing my 16' pontoon to be a fishing only vessel and considering removing the 1983 50HP Mercury 2-stroke.  The mercury ran last summer, I winterized it and the boat was kept in the garage over the winter.  

 

I imagine the engine won't last too much longer and since the boat has brand new decking and is completely refinished, I am getting hesitant to put holes in near the console to connect the steering cable and throttle.  I figured when the motor goes, I'd just remove it and only use the trolling motor.  However, I am now considering proactively removing the motor and going with the TM only.  So, I am curious if anyone can give me an estimate on how fast my boat would travel with the trolling motor only.  That would be a big help to consider my options.  If I remove the engine, I'd be left with this:

 

• 16' pontoon
• 5 high back fishing chairs
• Typical small center console for a pontoon
• 2 butt seats outside the pen up front
• Hummingbird fish finder

 

I have a 112 lb, 36v Minn Kota Ulterra ready to install and I don't take much gear.  I'll only use this boat on my home lake which is 3.5 miles long and roughly 330 acres total (so a small body of water).  Based on where my house is located, the farthest run back home (or out to a fishing spot) would be 2.5 miles.  So, I was wondering if I could get some ideas on how fast the pontoon would move to help decide if I should just take of the Mercury now.  

 

My thinking is:  If I only would expect to get 2-3mph, I might keep the mercury on (assuming it is still running this summer).  If I would get 6-8 mph, I'd only have a  20-30 minute trip home (max), if needed, and I would consider removing the mercury and eliminate the hassle of keeping fuel mixed and winterizing, etc.

 

Thanks!

I’m guessing that your pontoon would have more friction drag than my fiberglass boat but I really don’t have any way to know for sure.  With that being said I have the same trolling motor on it.  I have 3 new 31 series batteries on it.  Sometimes I put it on high to cross a cove or move down a bank.  My gps rarely shows 3 mph.  It is normally 2.8 or 2.9.  You might want to keep the outboard.

If you break 1.5 you are REALLY lucky.  Would be way better to put a small tiller outboard on it.  Trolling motor and pontoon are not going to get you anywhere.

Just as a comparison, my canoe with gear and me weighs around 450lbs. With a 30# TM I can hit 2.8mph full out on a calm day - tail wind would increase that, head wind decrease.

 

That's 1# thrust for every 15lbs mass to reach just under 3mph

 

Know what your pontoon with everything weighs? Quick calc based on weight and TM thrust will get you in the ballpark.

You can go pretty fast with a electric motor on your pontoon, just not the motor you have. Motors that have the same output as an 8 horse gas motor can cost almost $5,000. 

I just did a search and look around.

 

General consensus is that 1hp is around 75#-100# thrust - so your 112# TM is equal to a 1.1-1.5hp motor.

 

Not going to get you anywhere fast.

I have a 70lb thrust on my pontoon, maybe 2 mph, I have a motor on the back though.. it’s the wind that will get you. A few mph head wind and your stalled. Pontoon boat catches a lot of wind.. I’ve gotten blown around and it’s nice you just go and start the engine to motor out of a grounding situation. I even leave the motor partially in the water sometimes to keep for getting pivoted around. 

All,

Thank you for the thoughtful and helpful responses.  It is clear that I'll need/want an outboard.  So, even when the '83 Mercury goes, I'll likely want to replace with something above and beyond the TM to power the boat.  I'll go ahead and start cutting holes.  

 

 

On 5/8/2021 at 8:33 PM, T-Rick said:

I imagine the engine won't last too much longer

Those old 50s were indestructible.  Hook it back up and do normal maintenance.  A pontoon without normal outboard power is not very safe.  It only takes a brisk breeze to blow them off course even with a trolling motor.

I know this is a bit old but I have a 4.5 meter pontoon/party boat with a lot of gear I have 2 120lbs trolling motors on the back and can travel all day at around 5 Kmph not exactly fast but relaxing, flat out I get around 8 Kmph .

Cheers

Mark