Top speed

[Dirk Diggler480]

Just a general question. Never owned a pontoon before.
But in laws have a 2011 Sunsation Premiere Tritune 23ft with Honda 150 4stroke.
This boat will only do 20mph no matter what I do.
Two people.
Trim doesn’t matter.
Best my knowledge boat is in stock form.
I have not looked at the prop yet.
Is this typical speeds or is it way low. I would think this is slow.
Trying to remember last outing rpm was just over 6000
Speedo is way off but GPS says 20mph
Boat does have some algae growth I plan to clean off. I’m told it can slow it down a lot.
It stays in the water.
I’m gonna get it out of water to clean and service it.
Make sure not taking on water.
I do notice it seems last 1/4 throttle changes nothing in relation to rpm.
As if there’s a cable that has too much slack and it’s not going full throttle

 

[Scott Danforth]

If your hitting 6000 RPM, then you probably are getting full throttle

If your motor is too low, you will plow and not perform

If the motor is too high, you ventilate the prop

 

[racerone]

Could be a rev limiter.----Try a prop with 4" more pitch and test run.

 

[Chris1956]

Do what you can to optimize, as was suggested. Pontoon boats are displacement hulls, for the most part. as such, 20MPH is not the best they can do, but is close. My neighbor has a 24' pontoon with a 150HP Yammie. He gets 22mph.

 

[jlh3rd]

for reference...fyi....and fwiw:
I have a 2006, Lowe, twin 25" tubes , 24' pontoon boat. Purchased used.
It came with an '05 Merc 4 stroke, efi, big foot. With just me, on a cool spring day, cold water, I might hit 21 mph.
Currently, I now have a 2021 Merc 115 hp, CT engine, purchased new.
Same parameters, I could see 26mph, WOT, 5800 rpm's....using a merc 4 blade 14x14 prop.
Using a merc. 3 blade 16x12, 6000 rpm's, I saw maybe 23 mph.
We need to know what rpm, how many people, what prop size. Also, tri toons are heavier. General consensus is tri toons require more hp by comparison to twin tubes.

 

[Chris1956]

OK, so what was the HP difference between the '05 Merc EFI and the newer engine in HP?

 

[jlh3rd]

sorry, went from a 60 hp to a 115hp

 

[Scott Danforth]

sorry, went from a 60 hp to a 115hp

And you are simply burning twice as much fuel for the same speed

Unless you add lifting strakes, the boat is limited at displacement speed

Even with lifting strakes, you're going to be sub 30mph with 150hp

For example, the forest River tritoon with 3 500hp motors just ran a bit over 100mph at lake of the Ozarks

 

[airshot]

A couple on our local river has a tritoon with twin 300 hp out boards just to get to 40 mph....

 

[Dirk Diggler480]

So it’s mixed in what I should be seeing
Definitely bought o look at the prop condition and such
So many people say I should be seeing 25-30
If I could get 5 more out if it would feel it’s pretty good
Just like to get a little more for trying to get out of storms
Pulling two small kids in tube I can’t get them over the wake to the outside
It’s very close but just not enough speed

 

[airshot]

So it’s mixed in what I should be seeing
Definitely bought o look at the prop condition and such
So many people say I should be seeing 25-30
If I could get 5 more out if it would feel it’s pretty good
Just like to get a little more for trying to get out of storms
Pulling two small kids in tube I can’t get them over the wake to the outside
It’s very close but just not enough speed

30 mph is asking an awful lot out of a pontoon unless you have a really big motor on it, really big !!

 

[Scott Danforth]

So many people say I should be seeing 25-30

25mph maybe as there are no lifting strakes on your pontoon

to go faster you need more power and lifting strakes

then again, forest river just took a stock trifecta pontoon to lake of the ozarks with 3 500hp outboards and only managed to get 100mph. Had they stripped off the arch, furniture, coolers, etc. they could get over 125

 

[cyclops222]

W ho REALLY EXPECTS a pontoon to run like a V hull ?
Rubbish talk.

 

[Water logged]

The 24 ft Sun Tracker I had with lifting strakes and 115 hp would hit 31 mph gps.

 

[Scott Danforth]

with lifting strakes

the magic words there......

 

[jlh3rd]

So it’s mixed in what I should be seeing
Definitely bought o look at the prop condition and such
So many people say I should be seeing 25-30
If I could get 5 more out if it would feel it’s pretty good
Just like to get a little more for trying to get out of storms
Pulling two small kids in tube I can’t get them over the wake to the outside
It’s very close but just not enough speed

so, to repeat. You can't go by what "some people say" You have to go by what your boat is telling you and those of us that will speak the truth.
You said you were a little over 6000 rpm. And you implied or said 2 on board.
My rpm range on my 2021 merc is 5-6000.
Now you're talking about pulling tubes. More weight.
My WOT rpm with my 4-14x14 was 5800, just me. Top speed close to 27. But adding a couple of adults and 5 kids on 2 tubes lugged me down to 5300-5400 rpm's and slower in turns and speed was below 18. I couldn't sling them out either.
There isn't a 4-14x13 prop that fits my motor so I ended up with a 3-16x12. At 6000 rpm, just me, I see about 23 mph. But I can hit 6150 @WOT , over my limit. But this prop gave me 5600-5800 +/- under a good load and WOT. I could sling the teens now, could hold 20 mph.
Point? There is no magical prop. I traded speed for torque.
You're at 6000 rpm now, 2 people. You want to sling tubes around? You have to reduce your pitch to keep those rpm's up under load.
Top end with no load will suffer.
Maybe I'm wrong being you have 150 horses. Dunno.

 

[Dirk Diggler480]

Sorry about being slow to respond, I appreciate everyone’s input. I don’t get notifications when someone responds in here. I just have to remember to check.

 

[Dirk Diggler480]

Ok to follow up.
GPS 20, had 4 people in boat and 3/4 tank of fuel. 20mph at best. I know know I was carrying 3-4 people worth in the center toon.
Now that I’ve had time to get boat out of water for servicing and checking things over here’s what I’ve discovered
The toons are covered in algae. It stays in water. It’s bad. I can see where it would cause some drag for sure, it’s think and rough
I’m cleaning this up tomorrow. Here’s a pic of the prop number in attachments. Could it be wrong prop?
I also found the center toon was very full of water.
I have a video that shows a stream and it goes on for 5 minutes like this screen shot
I’m estimating at 14gpm flow like a garden hose and 5 minutes
Around 450-500lbs of water.
The weight is a few people
Also the weight is holding boat deeper in water.
But also guys, this boat has lifting strakes.
People tell me this boat should do 30
I’m hoping to get 25mph ….fingers crossed after this work
Gonna change oil and water pump while out of water
So in regards to the tach…I WAS WRONG. The tach is ****. When I looked at it last outing it was 6200…then I tapped it and we’re at 10,000, then tapped it again and 2000….so I have a broken tach to deal with.
I have no idea what rpms I’m turning but it doesn’t sound like 6200. I’m guessing 52-5500. It’s not screaming.
So I don’t know where to go with the prop

 

[jlh3rd]

well, right out'a the box, there should be no water in any toon...period.
First and foremost, you have to find that leak.
Most common areas to leak are at the toon section seams, and the brackets attaching the toon to the deck.....I've had both.
I don't have a center toon so there may be differences.
According to accredited sources, you cannot/should not pressurize a toon more than 3psi. Some say 5. I used my shop vac and a hose rigged to fit inside my toon's air plug, then used a spray bottle of soapy water to find my leaks. Luckily, my welder had easy access to the leak points.
My toon sections each had a plug on top. I checked for leaks every sping/fall by unscrewing them and listening for air escaping/entering. If I heard nothing, then out came the shop vac.
Sorry, but your performance #'s will not mean anything until you verify all of your toons are air tight.
prop is 14.8" diameter by 17" pitch. Looks like a 3 blade. The # of blades, diameter and pitch ALL affect performance. So do different manufacturers and correct or optimum motor height. So does weight. Again, we cannot tell you what prop you need ( I should say"start with") until you fix all of your problems.
I wouldn't spend anymore money until I verified my toon integrity.