New here, New Pontoon and a few questions

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BADsDAD
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New here, New Pontoon and a few questions

#1 Post by BADsDAD » Mon Jun 04, 2018 8:12 am

Hi all! We just got our first pontoon boat after having a small bass boat for years and I hope you guys can help me with a couple of questions.

1. Current prop is 14X13P - Engine is Merc 90 elpto - boat runs about 17-18 mph at 5500 but WOT will run right up to 6400 instantly, although I am afraid to keep it there to find top speed at this RPM.
So, I used the Merc prop selector and it recommended a 13.75X15 or 13.25X16 prop. Well, I priced them in aluminum and they were around 150 shipped so I was looking around and found a used but like new Merc SS prop RH 14x15P for 150 shipped on ebay, so I bit. Any guess on how much this will help?
Any advice to getting this boat to 21-22 mph would be appreciated as it just seems under considerable drag (this is with only ~650lb of people on board)
The motor is on the lowest hole so I wonder if it is too low. How can I tell?
Also, adjusting trim seems to have little effect, which may be expected on a pontoon, but not at all what I am used to.

2. I am adding a trolling motor to the front and have purchased a 2 bank on-board charger. How do you guys typically install these with the batteries so far apart? do you drill through the deck and run an extension alllll the way to the front battery and mount the charger in the back, or?
'08 Sun Tracker Fishin Barge 21
Mercury 90 ELPTO

Soonertoon
Posts: 333
Joined: Sun Apr 06, 2014 8:19 pm

Re: New here, New Pontoon and a few questions

#2 Post by Soonertoon » Thu Jun 07, 2018 8:39 am

Welcome to the Black Art of props where there is no cut and dry fix. Before I answer or try to anyway, clarify something. You can run 6400 RMP at WOT, correct? If so, you are over where it should be which is 5500-6200 RPM at WOT.
IF that is correct, you will drop the WOT RPM back to about 5800 with the increase in pitch alone. From the motor safety side you have a win. Staying the same diameter wont have any plus or minus effect unless you went to a cupped prop.
Remember that pontoons tend to like diameter more than they like pitch to a certain degree. You are a displacement hull now. Forget getting up on plane and reducing drag. In a two log boat with a 90 , that's not gonna happen. EVER. lol. Your goal should be propping that boat to make the most efficient use of the power available. Pontoons drag a ton of water. Blade surface is where you will get your biggest gains. Most pontoon props are big mouse eared blades as opposed to the sleeker designs used on v hulls. Shes never gonna be what you had in terms of speed.
Regarding trim, your only going to get so much bow rise which isn't much before you lose grip. Motor height does play a role. these damned things are butt heavy and I have seen several including mine that were too low in the water from the factory. A one hole raise made a drastic difference, however that is just my boat. Raise it up one hole and try it. You will know quickly if its too high.
Let us know what you find out in your test run. good luck and welcome to the world of Pontoons
Broken Arrow Ok
2014 G3 Suncatcher
115 Yamaha 4 stroke
Paradise Cove Marina on Ft. Gibson Lake

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Marc K
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Location: Eustace, TX

Re: New here, New Pontoon and a few questions

#3 Post by Marc K » Thu Jun 07, 2018 5:11 pm

Soonertoon wrote:
Thu Jun 07, 2018 8:39 am
Welcome to the Black Art of props where there is no cut and dry fix. Before I answer or try to anyway, clarify something. You can run 6400 RMP at WOT, correct? If so, you are over where it should be which is 5500-6200 RPM at WOT.
IF that is correct, you will drop the WOT RPM back to about 5800 with the increase in pitch alone. From the motor safety side you have a win. Staying the same diameter wont have any plus or minus effect unless you went to a cupped prop.
Remember that pontoons tend to like diameter more than they like pitch to a certain degree. You are a displacement hull now. Forget getting up on plane and reducing drag. In a two log boat with a 90 , that's not gonna happen. EVER. lol. Your goal should be propping that boat to make the most efficient use of the power available. Pontoons drag a ton of water. Blade surface is where you will get your biggest gains. Most pontoon props are big mouse eared blades as opposed to the sleeker designs used on v hulls. Shes never gonna be what you had in terms of speed.
Regarding trim, your only going to get so much bow rise which isn't much before you lose grip. Motor height does play a role. these damned things are butt heavy and I have seen several including mine that were too low in the water from the factory. A one hole raise made a drastic difference, however that is just my boat. Raise it up one hole and try it. You will know quickly if its too high.
Let us know what you find out in your test run. good luck and welcome to the world of Pontoons
Great post.

This is the kind of information that helped me understand!
I'm a lifelong boater with zero pontoon experience until now. It requires a whole different way of thinking - and I love it!

Marc
Big and ugly but we love our 1999/2000 Crest II DL with a Yamaha F115

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wwind3
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Location: Lake Livingston Tx

Re: New here, New Pontoon and a few questions

#4 Post by wwind3 » Fri Jun 08, 2018 4:20 am

Hi-welcome aboard! I'm running a 13 x 16 pitch on my 20 ft Lowe SS204 with front and rear fishing seats--so only a trolling motor and fishing seats up front----so I can trim up pretty good. My SS prop gets me 27 gps on my 90 Merc Optimax. Strangely the same prop specs in my spare aluminum prop gets me 28-29 with just me in the boat--go figure...

My motor gives overrev alarm at about 5850 rpms-so I can run right at max rpms and get my speeds--which I like. I repitched my SS prop to 17 lower Wide open rpms and actually lost speed at max rpms of around 5450-so repitched it back to 16. btw--have had my SS prop rehubbed twice---spun out my hubs --prop really works hard on a pontoon-like pushing a giant dumpster through the water! Esp 2 toon without lifting strakes.

Re motor setup-set motor so cavitation plate when motor is tucked all way in is even with bottom of motor mounting pod---too low and you will throw water around lower unit which will slow you down-too high and you will blow out and cavitate ==esp if too much weight in front of boat. Good luck!

Enclosing pic of mine at 27 gps==moving lots of water!
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2009 LOWE SS204 25in logs
90 Merc Optimax
Motorguide W55 Wireless
Underskinning
28 GPS

BADsDAD
Posts: 14
Joined: Thu May 31, 2018 2:05 pm

Re: New here, New Pontoon and a few questions

#5 Post by BADsDAD » Sat Jun 09, 2018 5:04 pm

Thanks guys! I just went out with the new prop which is a 14.5X15 Merc Vengeance SS (48-16312A46) and I gained only about 1-2 mph and WOT is still easily 6200 (it was 6400 before). Last prop was 14X13 Aluminum.

So, I don't know where to go.. Should I maybe go to a 14.5X17 (48-16314A46) ? My top speed is only 18-19mph but she wants to pull above 5500 (rating for my motor) really bad. I mean, just going from 5500-6200 takes me from 18 to 22mph very quickly and probably faster but I don't want to hold it at those revs.

It's a real pain to keep from over-revving it. Kinda takes some of the fun out of pulling the kids in the tube :-( Man, I wish this was easier.. this seems like it is going to cost me a fortune to find the right prop.
'08 Sun Tracker Fishin Barge 21
Mercury 90 ELPTO

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wwind3
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Re: New here, New Pontoon and a few questions

#6 Post by wwind3 » Sun Jun 10, 2018 4:18 am

....definitely try the 17 pitch.....
2009 LOWE SS204 25in logs
90 Merc Optimax
Motorguide W55 Wireless
Underskinning
28 GPS

BADsDAD
Posts: 14
Joined: Thu May 31, 2018 2:05 pm

Re: New here, New Pontoon and a few questions

#7 Post by BADsDAD » Sun Jun 10, 2018 7:13 am

wwind3 wrote:
Sun Jun 10, 2018 4:18 am
....definitely try the 17 pitch.....
Thanks, wwind3. I think (maybe) I may know where I have been going wrong using the online prop selector. My boat is a 21.7' but NADA shows the weight at 1680lbs with the 25hp engine. Now, I know the 90 weighs ~200lbs more than the standard 25hp engine, but that only puts the boat at around 1900 dry. If I change the boat length to 19' - the prop selector changes boat weight to 1983lbs and recommends a 13x17.

But, the current prop is a 14.5X15. Would you try the 14.5X17P Vengeance SS prop, or the 13.125X17 Vengeance SS? The sticker on the motor says "rated RPM 5500". Should I shoot for 5500, or 5250 or? I guess I am trying to determine how much RPM loss the +2P will give me with the SS prop. I only dropped 200RPM by going +2P AND switching to Stainless. I am temped to go back to aluminum and don't really care either way as what I want is the performance, couldn't care less about the shiny SS.

Damn, this really is a black art!
'08 Sun Tracker Fishin Barge 21
Mercury 90 ELPTO

BADsDAD
Posts: 14
Joined: Thu May 31, 2018 2:05 pm

Re: New here, New Pontoon and a few questions

#8 Post by BADsDAD » Sun Jun 10, 2018 8:46 am

Well, so given the good reviews on the SpitFire 4-blade prop, I ordered a 13X17 based on the Merc prop selector for an 18' toon which weighs right inline with what my Tracker supposedly weighs. I'll report back on how this one works out.
'08 Sun Tracker Fishin Barge 21
Mercury 90 ELPTO

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wwind3
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Location: Lake Livingston Tx

Re: New here, New Pontoon and a few questions

#9 Post by wwind3 » Sun Jun 10, 2018 2:02 pm

lol-----it is a crap shoot! Never tried a 4 blade prop. My aluminum merc prop is 1-2 mph faster than my stainless---same diameter and pitch---go figger. But with the stumps in my lake I'm a little gunshy of an aluminum prop-----dinged a couple just going slow--really messed them up
2009 LOWE SS204 25in logs
90 Merc Optimax
Motorguide W55 Wireless
Underskinning
28 GPS

BADsDAD
Posts: 14
Joined: Thu May 31, 2018 2:05 pm

Re: New here, New Pontoon and a few questions

#10 Post by BADsDAD » Sun Jun 10, 2018 3:44 pm

yeah, but if this one works out like I hope, I may buy the SpitFire X7 and keep the aluminum as a spare.. I just need to get in the right WOT RPM range. It's a pain to have to worry about over-rev all the time.

The other thing I noticed about the larger SS prop was it was much harder to turn the steering wheel at 5500RPM than the aluminum it replaced, maybe that's expected, I dunno.. But there is no way my wife could have turned it.
'08 Sun Tracker Fishin Barge 21
Mercury 90 ELPTO

Soonertoon
Posts: 333
Joined: Sun Apr 06, 2014 8:19 pm

Re: New here, New Pontoon and a few questions

#11 Post by Soonertoon » Mon Jun 11, 2018 9:43 am

BADsDAD wrote:
Sun Jun 10, 2018 3:44 pm
yeah, but if this one works out like I hope, I may buy the SpitFire X7 and keep the aluminum as a spare.. I just need to get in the right WOT RPM range. It's a pain to have to worry about over-rev all the time.

The other thing I noticed about the larger SS prop was it was much harder to turn the steering wheel at 5500RPM than the aluminum it replaced, maybe that's expected, I dunno.. But there is no way my wife could have turned it.
You are still getting to much slip. As I stated earlier, you get as much or more benefit form blade surface area as you do with pitch. Despite the claim that this prop is for pontoons you need to possibly look at the blade shape and if its not a big old mouse eared wheel, time to get out of the Mercury line up I would try calling this place ; Boat City Prop Shop (405) 632-2844 in OKC, OK. these guys know their business and will work with your feedback to get you where you need to be. Trust me., they are EXCELLENT at what they do. Ive used them and went thru two props before we got the one dialed in I have now. Let you return the ones you don't want if they aren't scuffed up.
Broken Arrow Ok
2014 G3 Suncatcher
115 Yamaha 4 stroke
Paradise Cove Marina on Ft. Gibson Lake

BADsDAD
Posts: 14
Joined: Thu May 31, 2018 2:05 pm

Re: New here, New Pontoon and a few questions

#12 Post by BADsDAD » Mon Jun 11, 2018 4:38 pm

Soonertoon wrote:
Mon Jun 11, 2018 9:43 am
You are still getting to much slip. As I stated earlier, you get as much or more benefit form blade surface area as you do with pitch.
This makes sense as my actual speed with the 2 props I have tried is considerably less than the Merc prop calculator estimates.

Both the BlackMax 13P that it came with and this Vengeance 15P look pretty mousy..

Image

They say the 4 blade spitfire helps with slip but we'll see how that goes this weekend.
'08 Sun Tracker Fishin Barge 21
Mercury 90 ELPTO

Soonertoon
Posts: 333
Joined: Sun Apr 06, 2014 8:19 pm

Re: New here, New Pontoon and a few questions

#13 Post by Soonertoon » Tue Jun 12, 2018 8:13 am

BADsDAD wrote:
Mon Jun 11, 2018 4:38 pm
Soonertoon wrote:
Mon Jun 11, 2018 9:43 am
You are still getting to much slip. As I stated earlier, you get as much or more benefit form blade surface area as you do with pitch.
This makes sense as my actual speed with the 2 props I have tried is considerably less than the Merc prop calculator estimates.

Both the BlackMax 13P that it came with and this Vengeance 15P look pretty mousy..

Image

They say the 4 blade spitfire helps with slip but we'll see how that goes this weekend.
A 4 blade will help in the slip category but DO NOT expect increases in top end. I run a 4 blade on my 22 ft with a 115 Yamaha. I gave up 2 mph on top end for the ability to have much more efficient use of power thruout the rpm range. My top end is 25 now. I run WOT less than 10% of the time.
Let us know
Broken Arrow Ok
2014 G3 Suncatcher
115 Yamaha 4 stroke
Paradise Cove Marina on Ft. Gibson Lake

BADsDAD
Posts: 14
Joined: Thu May 31, 2018 2:05 pm

Re: New here, New Pontoon and a few questions

#14 Post by BADsDAD » Sat Jun 16, 2018 5:17 pm

WOW! OK.. Now this is like a whole different boat with the SpitFire 4-blade 13X17! I gained 5MPH GPS (18 to 23) with 5 of us in the boat and bimini top up on rough whitecapping water and it pulls 2 kids in the big couch tube at 21-22 right at 5400 RPM making it much easier and more fun since I can leave it WOT while I pull them.

As an added bonus, the holeshot is much much better and it doesn't blowout in turns like the last 2 props did AND it's MUCH easier to steer than the heavy SS prop was.

Really, it is more improvement than I could have hoped for. So, SO much better!

Interestingly, the boat now actually planes up much more level instead of the ass end plowing down in the water AND even with the really choppy lake today, no one was getting water thrown all over them at WOT like before. Water was being thrown as high as the bimini top, but not on my passengers.

So, new question - at WOT on this choppy water, it does feel like someone is taking a deadblow hammer to the floor. So, underpinning/under-skinning... Thoughts? Opinions??
'08 Sun Tracker Fishin Barge 21
Mercury 90 ELPTO

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wwind3
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Re: New here, New Pontoon and a few questions

#15 Post by wwind3 » Sun Jun 17, 2018 3:54 am

looks like you are getting there! Re: underskinning--absolute must! Smooths out the ride and I believe at higher speeds esp into the wind the underskinning acts like a wing and helps with bow lift and getting that tub outa the water. I actually can go 1-2 mph faster into the wind rather than downwind....

Yesterday I had 8 adults and a child onboard including 2 adults and the child in the front seats which I almost never do when running--still managed 20 mph gps with my little ole 90 Merc. Cruising at 4000-4200 rpm--16 gps… as a point of reference... Running the 13 x 16 3 blade SS prop. Comes out of the hole nicely even with a full load...
2009 LOWE SS204 25in logs
90 Merc Optimax
Motorguide W55 Wireless
Underskinning
28 GPS

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