Looking for more HP in my ST 21' NV strake toon.

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wrd1972
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Joined: Sun Jul 31, 2011 8:37 am

Looking for more HP in my ST 21' NV strake toon.

#1 Post by wrd1972 » Sun Jun 27, 2021 7:08 pm

Okay I currently have a 2008 Sun Tracker 21' PB with factory NV strakes. i also have a Merc 4-stroke 90hp that runs great, but cant handle heavier loads. I can normally get 34mph assuming the boat gets up on plain with around 700 pounds or less, but not much more.

Problem is that if i have guests and the weight exceeds around 800 pounds, the boat just wont get up on plane, and then I have a 16MPH gas guzzling tub of shit to drive around for the day.

If i had just another 3 or 4 MPH with a heavier load, then the boat would plane easily. 20 MPH is the magic speed at these straked boats get up on the water, but it aint gonna happen with the 90 with a geavier load.

I dont want a 115 since thats just a baby step upgrade. So I was looking at a 150 or 175 Merc Verado. Either of those would defintely get me up on plane, and provide a good bit more top-end MPH. The key is just getting the boat on plane with a heavier load and not nescesarrily higher top-end speed.

Thoughts?
2008 Sun Tracker Party Barge 21' 2 Log NV performance Package, 90HP 4 stroke Mercury. 37MPH avg. on GPS.

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Rick McC.
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Re: Looking for more HP in my ST 21' NV strake toon.

#2 Post by Rick McC. » Sun Jun 27, 2021 7:53 pm

My son has a 23 foot tri-toon with a Merc 150 FS, and it runs strong.
I have a 24 four foot tri-toon with a Honda VTEC 225 FS, and it’s bad-ass!

I’m a firm believer in the old adage; “buy as much HP as you can afford.” I’ve never heard anyone complain that they had too much HP.
Rick

Sights are for the unenlightened.

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steve1313
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Re: Looking for more HP in my ST 21' NV strake toon.

#3 Post by steve1313 » Mon Jun 28, 2021 2:31 am

Is your boat a TRITOON? If not, there's probably very little you can do. And it's probably not rated for a 150 or 175. A third toon gives the added buoyancy to support the extra weight. And extra strakes to help it "plane"
Steve
"Serendipity" - 2017 Sweetwater 2286 WB Tritoon w/ 150HP Yamaha
Slipped at Lake Anna, Virginia
Primary Residence: Richmond, Virgina
Lake House: Lake Anna, Virginia

wrd1972
Posts: 236
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Re: Looking for more HP in my ST 21' NV strake toon.

#4 Post by wrd1972 » Mon Jun 28, 2021 7:51 am

Not a Tritoon. But it has the largest strakes I think that have ever been added to a toon from what I can see. I know its not rated for a 150, but if it would physically mount up and not be much heavier, I still might consider it. Again, I just need that little extra ooomph to get it up on plane at 20MPH and after that, I dont really want to go much faster than what I currently do now at 34MPH. The boat works so well for me otherwise, I dont want to let it go assuming there is a solution to this one problem. Right now, its just on the verge of getting up. I have already stripped it of excess weight to see if that can help, and maybe underskinning could help to. I can hear the water grabbing the rear underside of the deck which must be hindering me a bit as well.
2008 Sun Tracker Party Barge 21' 2 Log NV performance Package, 90HP 4 stroke Mercury. 37MPH avg. on GPS.

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Marc K
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Re: Looking for more HP in my ST 21' NV strake toon.

#5 Post by Marc K » Mon Jun 28, 2021 8:52 am

My heavy old tub is a 25' with 115 HP, (2) small 23" pontoon tubes and no strakes. My top end speed running a light load is 27 MPH @ 5900 RPM and 23 MPH with six adults onboard while towing two more adults on our three person tube tube. Mine has heavy wood-framed furniture up front so the nosecones do not ever lift much at all - it's a matter of more or less plowing! (As evidenced by my large bow wakes :biggrin2)

I would think that 150 HP would easily reach all of your goals and then some. If you can hear/feel water grabbing the cross-members, then 115 HP with underskinng might bump you up to 20+ MPH - but I am sure that 150 HP will.

This video was with 4(5?) adults on board plus the people on the tube and we holding right around 25 MPH.

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

Steiner
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Re: Looking for more HP in my ST 21' NV strake toon.

#6 Post by Steiner » Tue Jun 29, 2021 8:23 am

All I will add is if you're considering putting a higher hp than what the boat nameplate states, make sure you're ok with the liability. You will not be able to insure it. If you are somehow able to get insurance by omission of info and there is a claim against you, the investigation will show the over rating and they'll use that to deny the claim. Sure lots of people are self insured but a consideration is still what if there's an accident and what will a lawyer do with the info of an over rated boat being involved.

Trust me, I'm half cowboy myself and not trying to be anyone's nanny or implying how anyone might operate their boat but just throwing out something that might not have been considered.

I'm not as bad as this guy from our local news though....
https://www.foxcarolina.com/news/georgi ... a7876.html
2019 G3 SunCatcher V322 SS tritoon, Yamaha F200
2019 F-150 XLT SuperCrew FX4, 3.5L EcoBoost Max Trailer Tow Package

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wwind3
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Re: Looking for more HP in my ST 21' NV strake toon.

#7 Post by wwind3 » Sun Jul 04, 2021 3:30 am

Would it be possible to add a center tube with strakes? Some like that are rated for at least 115 hp. Definitely add underskinning.
2009 LOWE SS204 25in logs
90 Merc Optimax
Motorguide W55 Wireless
Underskinning
28 GPS

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Rick McC.
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Location: Weeki Wachee, Fl

Re: Looking for more HP in my ST 21' NV strake toon.

#8 Post by Rick McC. » Fri Jul 09, 2021 3:22 pm

My tri-toon has two large lifting strakes on all three tubes, and is rated for 300 HP.
Rick

Sights are for the unenlightened.

Bamaman
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Re: Looking for more HP in my ST 21' NV strake toon.

#9 Post by Bamaman » Fri Jul 09, 2021 9:59 pm

Your boat is one of the fastest 2 toon boats I've ever heard about, but it just doesn't suit your needs.

I suggest you sell it and purchase a boat that does meet your needs. Or, quit carrying co many people/weights.

My 24' tritoon with a F150 runs great. And it fully meets our needs. The 150 hp motors are much stronger than the 115 hp's.
'12 Bennington 24' SSLX Yamaha 150

brumbyvet
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Location: Cherokee Lake, East Tennessee

Re: Looking for more HP in my ST 21' NV strake toon.

#10 Post by brumbyvet » Sun Aug 08, 2021 10:54 am

I have the same boat and motor as wed with mostly the same results. With just me onboard it tops out at 35-36 but start adding weight and it slows down considerably. My motor is also a 90 four stroke efi
but I wish I had gotten a 90 optimax. There is another nv pb on our lake but it has the optimax 90 .Top end is about the same but he can leave me setting from a dead start. I believe the extra torque would get me over that 19 mph hump much better.
2009 Sun Tracker Party Barge, NV Performance Package, 90 HP Merc 4 stroke
36 mph gps...
Cherokee Lake, Tennessee

U.S. Navy 1971-1977

willy13
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Location: Canandaigua Lake in NY

Re: Looking for more HP in my ST 21' NV strake toon.

#11 Post by willy13 » Fri Aug 13, 2021 1:39 pm

Install under skinning, the plywood will thank you! The constant banging of the water up against the plywood will eventually cause problems.

Prop it for the heavier load and you might get what you want without upgrading your outboard. If you are currently propped for a light load and you load it up, that 90 hp has to work too hard and thus is inefficient.

brumbyvet
Posts: 123
Joined: Thu Dec 25, 2008 5:13 pm
Location: Cherokee Lake, East Tennessee

Re: Looking for more HP in my ST 21' NV strake toon.

#12 Post by brumbyvet » Sun Aug 15, 2021 9:18 am

Our NV package came with a all aluminum deck so there is not any wood to get wet. That plus the strakes are the reason they perform so well for a two pontoon boat.
2009 Sun Tracker Party Barge, NV Performance Package, 90 HP Merc 4 stroke
36 mph gps...
Cherokee Lake, Tennessee

U.S. Navy 1971-1977

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