20' tritoon with a 150hp

[tms0425]

I agree, hard to believe, especially with the Verado version which is a bit heavier than the regular 150. We have a ton of Harris Cruiser 200's and Solstice 220's around here, mostly with smaller motors, since we're 60 miles from the factory. I've never heard of anything over 40.

[Dusto]

https://m.youtube.com/watch?v=AehUj-jkbdw

[COTTS4x4]

I think 48's a little high... but my 22' Sweetwater tritoon (without outside strakes) runs 44 with 3 people and 29 gallons of fuel. I had 12 adults on it this Sunday, with the top up in the rain and everyone piled under the bimini (toward the rear of the boat) and ran 36 mph with approx 23-25 gallons of fuel.

A friend of mine has a 24' Suncatcher tritoon, fully straked with a 200 Yamaha. With 2 people on board and only a couple gallons of fuel the fastest he's gotten out of it is 46mph. I haven't run mine with only a couple gallons of fuel and one or two people to see the top speed.

All these speeds are from gps since we both have Yamaha's and the speedometers clog when we unload off the trailers


Here's a pic of our two boats from Saturday, I had 6 adults and he had 4 adults and 3 kids and his boat couldn't keep up with mine.

[Dusto]

I have yet to test my top speed with a light load. The family is always on board. I am curious though. My 115 pushes us 31-33mph (GPS)whether we have 4-6 people. Pretty consistent.

I imagine I could break 35mph with a SS prop and a very light load.

Given those numbers I would be surprised if a 150hp didn't give me low to mid 40's.

The problem is there is not many 20' tritoons (with skin kit and lifting strakes) and a 150hp.

The original post wasn't all about speed. I am still curious how the fuel economy and reliability will be if I decide to go with the 150?

[jayw]

https://m.youtube.com/watch?v=AehUj-jkbdw

I know this is not about just speed, but since we're kinda on the topic... speed is a topic that's been debated here before, and I always remain incredulous. If someone claims better than 41ish, MAYBE 42ish, from a stock 20+ ft tritoon of any make with a stock 150 of any make, I would have to be on the boat with my own calibrated GPS or witness a calibrated radar reading to believe it. Period. Sorry I've just been around boats too long, and owned too many, to believe "fish stories". And I've been around long enough to see lots of claims fall flat when push comes to shove.

Thinking "well I have a 100 that does 30, so it only makes mathematical sense that a 150 will do 45" is inherently flawed. There are discussions abut this physics of this on the internet that can be found thru Google.

In any event, so he said 39.4 MPH top end @ 4500 RPM. I didn't hear 48. But wait - 4500RPM w/ 2 people on the boat? Again, something is dearly wrong. That Verado WOT range is 5800-6400. If he were running WOT @ 4500 RPM that motor would be so severely dogging he would *KNOW IT* if he's been around boats for any length of time - an experienced boater can feel a dogging engine like a sprained ankle. This would suggest, to me, either the tach is off (happens, happened to me last boat) or the boat is overpropped by 6-8"! The boat would be all but unusable to a seasoned boater. His expectation of 43-44 is "pie in the sky". Read the Merc test, this is what you might expect, ideal conditions, light load and good, tuned-in prop.

The claims we see here of 45MPH tritoons with 150s stock setups I find... highly optimistic. Not to insult anyone, but as the others have said, you should expect upper 30s to low 40s. By low 40s I mean if you hit 41, based on the Merc test of your proposed setup, consider yourself lucky. You better have nothing at all in the boat. And skip breakfast.

I run up along other tritoon/150s on the lakes where boating lanes allow for safe crossing WOT of several boats abreast. Some fall behind me, some run even, some pass, but NEVER EVER has one blown by me, or even passed me impressively. It seems always the Yamahas that run the fastest. And it's always the straked boats that slip past me, few MPH faster (strakes carry weight better too I think, another reason I plan to do it). I also see people claim - and I've said this before - 115s running 36, 37. Me feelings are the same. Maybe a stripped ultralight. There are twice as many TT/115 setups than TT/150s by me. Same drill, anyone who claims they can do so with a stock setup, I only ask that they prove it. I have NEVER EVER seen a TT/115 keep up with me WOT. They catch up to me a minute or two later in the no-wake.

Thinking something in the equation short of extreme modification (removing seats etc) will gain you, OR ANYONE, 6-10 MPH over what others are telling you here, I have to say, humbly, it's wishful thinking. I'm never too stubborn to be proven wrong, but I'm never too gullible to take overly optimistic claims at face value. I've been around boats since age 7 or so, owning my own for 25 years or so.

In any case if you get the 150 you will have a much more versatile boat, but if you expect even mid 40s you will be sorely disappointed. With all sincerity, good luck with the swap out. I hope you do it - and get the numbers you want from the boat.

[jayw]

I think 48's a little high... but my 22' Sweetwater tritoon (without outside strakes) runs 44 with 3 people and 29 gallons of fuel. I had 12 adults on it this Sunday, with the top up in the rain and everyone piled under the bimini (toward the rear of the boat) and ran 36 mph with approx 23-25 gallons of fuel.

A friend of mine has a 24' Suncatcher tritoon, fully straked with a 200 Yamaha. With 2 people on board and only a couple gallons of fuel the fastest he's gotten out of it is 46mph. I haven't run mine with only a couple gallons of fuel and one or two people to see the top speed.

All these speeds are from gps since we both have Yamaha's and the speedometers clog when we unload off the trailers


Here's a pic of our two boats from Saturday, I had 6 adults and he had 4 adults and 3 kids and his boat couldn't keep up with mine.

Not to start any arguments here, but something is wrong with this picture. 44 from that Yamaha, on that boat, with all that weight. With all due respect, sorry it's one of those cases where I'd personally would need to see the proof. 46 from the 200 sounds more in line. I don't expect you to care what I think, but since you posted your numbers...

The pictures don't really show anything, except that you are all having a good time.

[Matt in Houston]

Pitch, gearing, prop slip, and RPM = Speed. For every single rotation of a 15 pitch prop, assuming zero slip, it will move 15" ahead in the water.

So for a boat to run 44 mph, you would have to be spinning a 17 pitch prop at over 6000 RPM. Many pontoon/tritoon boats 22'-25' size are running 15 pitch props...which would require almost 7000 RPM to reach 44 mph, well beyond redline. This is estimated with a prop slip of around 10% which should be about right for most setups, and a gear ratio of 2 for the Yamaha 150 4 stroke. You can adjust it in the link below.

http://www.rbbi.com/folders/prop/propcalc.htm

[rancherlee]

If you think your current 115 could pull 35mph under ideal conditions then going to a healthy 150 mathematically puts you at 42mph (gave the 150 a 160 rating in my calculations) a 7mph gain it pretty good for only 35 hp (on paper). The older 1.7L 115's are pretty weak and the new 2.9L 150's are pretty strong so there is more than a perceived 35hp difference. To get to 48mph from 35mph would take a 205hp + engine on the back.

[COTTS4x4]

I have yet to test my top speed with a light load. The family is always on board. I am curious though. My 115 pushes us 31-33mph (GPS)whether we have 4-6 people. Pretty consistent.

I imagine I could break 35mph with a SS prop and a very light load.

Given those numbers I would be surprised if a 150hp didn't give me low to mid 40's.

The problem is there is not many 20' tritoons (with skin kit and lifting strakes) and a 150hp.

The original post wasn't all about speed. I am still curious how the fuel economy and reliability will be if I decide to go with the 150?

Sorry to have thrown your original post off track - As for reliability all the newer engine are extremely reliable. I looked at boats with a couple different engines and never found a single one in a brand or horsepower that stood out as the "black sheep." Its hard to differentiate the fuel economy mainly since it all depends how you run it. Personally I don't think there is a big difference in the 115 and 150. In theory the 150 wont have to work as hard, so if your trying to hold a speed of say 20 mph you may run a little less rpm's. Either way they are both 4 cylinders and weight is close to the same.


I think there are some issues with the prop/speed calculators... they don't take in consideration for pontoon diameters, strake sizes, boat weight, distribution, etc. Some of the newer tritoons such as mine have the center toon mounted 2" lower than the outer, the strakes all match so when at WOT my outer toons aren't dragging/resisting nearly as much as my center toon. The Suncatcher in my example has all the same size pontoons so he has equal drag on all 3 even when at WOT on the strakes. The weight distribution on this boat carries a lot more weight further forward keeping more of his boat in the water, where my boat rides with a lot of the toons out of the water when trimmed out perfectly at WOT. Next time I have it out I'll shoot a video of it and the GPS.


Like said earlier it doesn't really matter as long as everyone on board is having a good time!

[Matt in Houston]

The boat configuration has nothing to do with the way a prop calculator works. It simply relies on numbers but will still be accurate since it's all a calculation based on the four parameters that mathematically calculate the speed.

So for example, your boat might be very efficient which allows you to reach 6100 rpm with a 17 pitch prop. Where as a boat that doesn't have strakes or special pontoons can only reach 5500 rpm. The calculator only cares about the numbers, so your boats upgrades have indeed made a positive effect by allowing you to put a higher RPM into the calculator.

Hitting 44 mph with a 15 pitch prop on a Yamaha 150 4 stroke with 2:1 gearing should be mathematically impossible unless someone is running with a current. It doesn't matter if the boat only weighs 500 lbs, the pitch and rpm limit of the motor will not spin the prop fast enough to move at that speed. If a person has the power to run higher RPMs and wants to go faster, they will have to increase pitch.

Hope this helps!

[COTTS4x4]

The boat configuration has nothing to do with the way a prop calculator works. It simply relies on numbers but will still be accurate since it's all a calculation based on the four parameters that mathematically calculate the speed.

So for example, your boat might be very efficient which allows you to reach 6100 rpm with a 17 pitch prop. Where as a boat that doesn't have strakes or special pontoons can only reach 5500 rpm. The calculator only cares about the numbers, so your boats upgrades have indeed made a positive effect by allowing you to put a higher RPM into the calculator.

Hitting 44 mph with a 15 pitch prop on a Yamaha 150 4 stroke with 2:1 gearing should be mathematically impossible unless someone is running with a current. It doesn't matter if the boat only weighs 500 lbs, the pitch and rpm limit of the motor will not spin the prop fast enough to move at that speed. If a person has the power to run higher RPMs and wants to go faster, they will have to increase pitch.

Hope this helps!

I understand what your saying - makes sense now. Thanks!

[rockhound]

yep, unless you have achieved negative slip or are running a flux capacitor it would be impossible.

[Matt in Houston]

I'm glad that we've had this brief discussion. I think it's important to understand the prop "101" principles if you really want to maximize the performance of your boat. Motor height, prop pitch, and prop diameter are three things that can easily be adjusted to help maximize your performance.

It still amazes me how many dealers have no idea how to properly setup a boat and sometimes the customer has no idea anything is wrong. Maybe they are just being very conservative with the rigging. For some this might be fine, but I personally don't like leaving performance on the table when its almost free for the taking just by making a few simple changes.

Here is an excellent article I read yesterday, and I recommend reading it for some additional educational on the subject.

http://www.vicprop.com/propeller101.htm

And one more, a little more basic with some illustrations...

http://www.turbo-props.com/prop101.php

[jayw]

I think there are some issues with the prop/speed calculators... they don't take in consideration for pontoon diameters, strake sizes, boat weight, distribution, etc. Some of the newer tritoons such as mine have the center toon mounted 2" lower than the outer, the strakes all match so when at WOT my outer toons aren't dragging/resisting nearly as much as my center toon. The Suncatcher in my example has all the same size pontoons so he has equal drag on all 3 even when at WOT on the strakes. The weight distribution on this boat carries a lot more weight further forward keeping more of his boat in the water, where my boat rides with a lot of the toons out of the water when trimmed out perfectly at WOT. Next time I have it out I'll shoot a video of it and the GPS.

Prop calculators show show THEORETICAL speed. Boat characteristics can only reduce that speed. You can't increase theoretical speed unless you change the numbers - gear ratio, RPM, slip, or pitch.

I can spin a 19P SS prop to 6000RPM. Alas, I have a 2.5:1 gear ratio. So I am at 12% slip. Not great but in the typical range. Theoretical top speed for me is 43MPH, achievable only with virtually no slip.

I do like the flux capacitor idea. And I like this calculator:
http://www.mercuryracing.com/propellers ... ulator.php

[jayw]

I'm glad that we've had this brief discussion. I think it's important to understand the prop "101" principles if you really want to maximize the performance of your boat. Motor height, prop pitch, and prop diameter are three things that can easily be adjusted to help maximize your performance.

It still amazes me how many dealers have no idea how to properly setup a boat and sometimes the customer has no idea anything is wrong. Maybe they are just being very conservative with the rigging. For some this might be fine, but I personally don't like leaving performance on the table when its almost free for the taking just by making a few simple changes.

I agree, our dealer - a great guy whom I consider quite knowledgeable - sent us on our merry way with a prop that was/is a total mismatch for the boat. Probably OK on a 20' open bow or something, but for my setup terrible. 25-30% slip! They just don't have the time I think, to get involved with tuning every boat in. They'd spend all their time propping. Like you said they play it safe. Same with motor height. Play it safe, reduce complaints of cavitation etc.

With this boat, propping has made more of a difference than any boat I've ever owned. TT propping can be tricky.

Monday we will have the MIrage Plus back on the boat and the marina is lifting the motor one hole. That may give me a small boost in speed (thanks to increased RPM), but won't do the things for me that lifting strakes will do. But, I digress. This is not my post.