What's your top speed on 24' w/ 115 hp?

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Luke
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What's your top speed on 24' w/ 115 hp?

#1 Post by Luke » Tue Jul 14, 2015 5:01 pm

I'm curious what top speeds others are getting with 24' pontoons and tritoons with 115 hp. 22mph gps is my top speed with my Mercury 115 with factory prop . I haven't hooked up my tachometer yet so I don't know my rpms. Just wondering if anyone is doing much better with a 24'. I may upgrade to a larger motor in the future but want to see what I can get out of the 115 first since it would most likely be better on fuel. I added a 3rd toon which didn't really improve top speed but did improve the ride and blow out tremendously. I still need to underskin and add lifting strakes.

smoker62
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Re: What's your top speed on 24' w/ 115 hp?

#2 Post by smoker62 » Tue Jul 14, 2015 5:05 pm

Ran 25 gps with my Southbay . 27 with underskinning on a perfect day. Twin tube , 24' , 115 4 stroke , 4 blade spitfire prop.
2014 Crest Classic 250 SLR2 , Mercury 300 Verado Pro , Mercury Enertia Prop
2012 South Bay 522 , Merc 115 4S, Mercury Spitfire 4 blade prop-13 pitch light 25 mph gps, 11 pitch heavy - Sold

Luke
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Re: What's your top speed on 24' w/ 115 hp?

#3 Post by Luke » Tue Jul 14, 2015 5:25 pm

smoker62 wrote:Ran 25 gps with my Southbay . 27 with underskinning on a perfect day. Twin tube , 24' , 115 4 stroke , 4 blade spitfire prop.
27 is very respectable for a 24 foot boat with a 115. Is the spitfire prop stainless steel?

smoker62
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Re: What's your top speed on 24' w/ 115 hp?

#4 Post by smoker62 » Tue Jul 14, 2015 5:36 pm

No, just a 4 blade aluminum. Much better than the stock 3 blade black max though. No blowout in tight turns, better top speed and pulling power.
2014 Crest Classic 250 SLR2 , Mercury 300 Verado Pro , Mercury Enertia Prop
2012 South Bay 522 , Merc 115 4S, Mercury Spitfire 4 blade prop-13 pitch light 25 mph gps, 11 pitch heavy - Sold

willy13
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Re: What's your top speed on 24' w/ 115 hp?

#5 Post by willy13 » Tue Jul 14, 2015 6:11 pm

24' pontoon, no lifting strakes, no underskinning.
115hp Yamaha 4-stroke with stainless 14x13 cupped prop. WOT is 5700 rpm.
With a light load I can run 25 mph (GPS).

RcgTexas
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Re: What's your top speed on 24' w/ 115 hp?

#6 Post by RcgTexas » Tue Jul 14, 2015 6:16 pm

I still need to underskin and add lifting strakes.
That will help..............but be careful with the strakes, they aren't just angles welded to the sides. and aluminum , especially the thin stuff pontoon logs are made of don't fare well with a lot of heat concentrated in one spot. A Good aluminum welder will know that.
1995 beachcomber conversion to tritoon with Honda 135 ,

Link to rebuild [url=http://www.pontoonforums.com/viewtopic.php?f=16&t=19016][Knot Normal][/url]

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Kramfam
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Re: What's your top speed on 24' w/ 115 hp?

#7 Post by Kramfam » Tue Jul 14, 2015 8:58 pm

28mph with two tubes and 4 adults, factory 3 blade prop. No strake but the toons have a hull shaped bottom which allows them to plane. Does anyone think my performance would better with a 4 blade spitfire? Right now I have no cavitation problems at all. Trying to figure out what I would gain for the extra expense.
2014 Sylvan Mirage Cruise 8524
27" RPT tubes w/underskinning
2014 115hp Mercury 4 stroke
Previous: 2004 Four Winns 22' Horizon, 270hp

Luke
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Re: What's your top speed on 24' w/ 115 hp?

#8 Post by Luke » Wed Jul 15, 2015 1:24 am

I have found a good welder to weld the strakes on and I've been looking at other boats with strakes to get ideas. I'm just not sure where to get the metal. Does anyone know where to get pre-made strakes or do most people buy the metal and get it bent?

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rancherlee
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Re: What's your top speed on 24' w/ 115 hp?

#9 Post by rancherlee » Wed Jul 15, 2015 5:04 am

Kramfam wrote:28mph with two tubes and 4 adults, factory 3 blade prop. No strake but the toons have a hull shaped bottom which allows them to plane. Does anyone think my performance would better with a 4 blade spitfire? Right now I have no cavitation problems at all. Trying to figure out what I would gain for the extra expense.
I'd say probably not, unless your slip numbers are in excess of 30% with your current prop. It all depends on your current prop, Rpms, and speed to figure out how efficient it is.
1988' Kennedy 20' "Haley's Comet"
Rebuilt 2016 with 25" single strake outer tubes and a 25x23" straked U-tube
2003 Suzuki DF140 - Yamaha 9.9HT kicker - 39.1@6300rpm

willy13
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Re: What's your top speed on 24' w/ 115 hp?

#10 Post by willy13 » Wed Jul 15, 2015 6:59 am

Luke wrote:I have found a good welder to weld the strakes on and I've been looking at other boats with strakes to get ideas. I'm just not sure where to get the metal. Does anyone know where to get pre-made strakes or do most people buy the metal and get it bent?
This place is out of Springfield, Ohio;
http://www.custompontoonboatkitsetc.com/index.html

A local metal supplier can certainly sell you 4'x8' sheets, shear them, and them bend them to your specs with a sheet metal break. You will just need to provide the design. They would be in 8' sections, but I doubt the welder would care.

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Ddancers
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Re: What's your top speed on 24' w/ 115 hp?

#11 Post by Ddancers » Wed Jul 15, 2015 7:19 am

SW240DF (25' 8") 115 Yamaha. was getting 27.3 MPH. After adding 2 Bimini tops (With two always open) and adding motor shaft extension now 22 MPH. Two 27" tubes not cleaned from last year. Do still get occasional blow out.
Sweetwater 2015 - 2 - 27" Tubes
240 DF LF150 Yamaha
Lifting Strakes Cap. 15 Per.
Long Shaft 31.9 mph.

Luke
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Re: What's your top speed on 24' w/ 115 hp?

#12 Post by Luke » Wed Jul 15, 2015 1:52 pm

What thickness aluminum is usually used for the strakes?

willy13
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Re: What's your top speed on 24' w/ 115 hp?

#13 Post by willy13 » Thu Jul 16, 2015 5:39 am

Luke wrote:What thickness aluminum is usually used for the strakes?
If my memory serves me, 1/8 inch. This is from me researching doing it myself over the winter. I never did the project, so I am watching yours. I am sure others could measure the ones on there boats.

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PommeToon
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Re: What's your top speed on 24' w/ 115 hp?

#14 Post by PommeToon » Thu Jul 16, 2015 7:14 am

1 person, does not seem to matter on fuel amount. Slight wind. 25-26 GPS verified. Aluminum 14x13 Hustler Prop. The boat is under-skinned.
Nick
1993 Lowe 257 Classic
1993 Evinrude V4 115hp VRO

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BobG
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Re: What's your top speed on 24' w/ 115 hp?

#15 Post by BobG » Thu Jul 16, 2015 7:48 am

24' tritoon.

7,500 foot elevation with a 12 pitch: 22 MPH
5,500 foot elevation with a 15 pitch: 24 MPH

I COULD run a 14" pitch at 7,500 feet, but my stainless is a 12 so I can also use it at 10,000 feet. Elevation really makes a difference. At 10,000 feet, my 115 only puts out 84 HP.
2012 Tahoe 24' Fish-n-Fun Tritoon, with Mercury 115 HP 4-Stroke
"Trine SS Cape" (Trying 2S Cape)
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