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Intrepid 43SY repower

Old 02-26-2021, 11:26 AM
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Default Intrepid 43SY repower

Who has re-powered an Intrepid 43SY? I have triple Yamaha 350s now, considering options....
Old 02-26-2021, 11:28 AM
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Triple Mercury 450R seem like the best option available in that range. My second choice would be triple Yamaha F425s.
Old 02-26-2021, 11:34 AM
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I want to stay away from the "R" engines, though I tend to agree that would be ideal. Triple 425s are heavy... curious real world performance for anyone with the Trip 425s or Trip 400 Merc?
Old 02-26-2021, 11:42 AM
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I can understand that. I would also suggest looking into the "R" engines a little more. It is not just racing anymore and come with a standard full warranty. I would also call Intrepid and have them share their experiences with the 450Rs.

Good Luck.
Old 02-26-2021, 01:14 PM
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go with quads. go big or go home man! that is a big, heavy boat!
Old 02-26-2021, 01:28 PM
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Even though its highly unlikely anyone other than a builder can get their hands on one....surprised that THT hasn't suggested twin V12 600's. Sure it makes no sense but who cares!
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Old 02-26-2021, 01:55 PM
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Originally Posted by Dkn1997 View Post
Even though its highly unlikely anyone other than a builder can get their hands on one....surprised that THT hasn't suggested twin V12 600's. Sure it makes no sense but who cares!
It's crazy that he could go from trips to twins- and gain horsepower......
Old 02-26-2021, 02:10 PM
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Originally Posted by rwlwhaler View Post
I want to stay away from the "R" engines, though I tend to agree that would be ideal. Triple 425s are heavy... curious real world performance for anyone with the Trip 425s or Trip 400 Merc?
I don't think you would benefit from going 400s over 350s or even 300s for that matter. My understanding is that the extra 50hp with the 400 is only in the top of the rev range where it is unlikely to be of any benefit in this type of boat.

I am thinking your best bet taking cost into consideration would be triple 300s Verados. The torque of the V8 would be of benefit over the smaller displacement and supercharged 350s. The Yamaha 425s sound like a good choice on paper but it's adding around another 600lbs to the transom and carries a pretty hefty price tag, probably in the neighborhood of $150,000. Triple 300 Verados would save about 500lbs over the F350s and be several tens of thousands cheaper than the 425s. Are you wanting more power than the current 350s offer?

You could try getting in touch with David Wade Marine on this forum. They are a big Mercury dealer and may have experience with a similar type of boat.
Old 02-26-2021, 06:27 PM
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I cannot imagine trip 300’s would perform well on that hull. Even though the new merc v8’s are awesome I think 350’s would be the minimum. Merc 450’s would be ideal if you could swing it or yamaha 425’s
Old 02-27-2021, 03:44 AM
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I am gonna be following this.. My wife & I been thinking about trading up from our 42' Harley to a 43' Intrepid SY & doing a repower right away (from Yamaha 350's). Whaler, what kind of numbers are u getting with the 350's? Do u have a trailer, or have u ever trailered?


Old 02-27-2021, 04:46 AM
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Originally Posted by rwlwhaler View Post
I want to stay away from the "R" engines, though I tend to agree that would be ideal.
I am told by some very knowledgeable people (specifically the guys ‘who know’ at Intrepid) that the 450R’s are extremely reliable engines - “Bulletproof” in fact was the description. They ship with 3 year warranty which can be extended to 6 years. Each unit is a hand built, blueprinted and tuned engine, with careful performance enhancements, assembled by a single master engine builder. What I didn’t realize is that ‘Mercury Racing’ is actually a completely different company than ‘Mercury’ which sells the stock Verado’s (of course there is a relationship between the two).

You should definitely reach out to Intrepid on this. As an Intrepid owner you know that they are extremely responsive regardless of whether you just took delivery of a new $1MM boat, or need information on your well-loved, 4th-hand 32 footer.

John
Old 02-27-2021, 04:55 AM
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While I have zero experience with that particular hull, I’d be looking at quad 300 V8s if they’ll fit. The price of those 4 engines only is $50k cheaper than triple 450Rs. Plus there are some additional 450R rigging components on top of the required DTS controls. We are going through this with a 42YF repower. The customer intended on triple 450Rs but is now going with quad 300 V8s.

One thing to keep in mind when rigging 450s is they require 1/2” fuel lines and pickup. This can be easy or damn near impossible, depending on the vessel.

The factory warranty for 300 V8s and 450Rs is the same. You get 3 years and have the option to buy 5 more years for up to 8 total years.

Last edited by davidwademarine; 02-27-2021 at 05:00 AM.
Old 02-27-2021, 05:27 AM
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Default 430 SY Repower

Below are factory sea trail reports for the 425's (5 year warranty) and 450r's.(6 year warranty). At 1200 + more pounds the 425's power to weight ratio goes south.

PERFORMANCE REPORT

TEST CONDITIONS
Date 1/28/2021
Driver Jeff E BOAT
Air Temp F° 58°F Make Intrepid
Seas in ft. 5.8 ft Model Evolution
Wind 24 to 30 mph Hull ID IBW43512I021
Wind Direction N Length 43'8"
Tides In/Out Incoming Fuel Capacity (g) 525
In/Off Shore Offshore Steering Mercury
Fuel Level 275 gal

ENGINES ENGINE HOLE/CAVITATION
Make Mercury Hole P 1+3↓ Cav P 2 7/8
Model 450 Racing V8 Hole C 1+3↓ Cav C 5 3/8
HP 450hp Hole S 1+3↓ Cav S 2 7/8
Number 3
Total HP 1350hp TIME TO PLANE
Shafts (2) 25" + (1) 35" No Tabs 9.6
With Tabs down 6
PROPELLERS Top Speed 63.1
Make Mercury
Model Revolution 4 XP RPM
Size 14.6" Max recommended 6400 RPM
Pitch 19P Max Port 6400
Blades 4 Max Center 6400
Max Starboard 6400
AVERAGES OF TWO DIRECTIONS
RPM GPS GPS GPH MPG RANGE TRIM
3000 19.5 29.5 0.659790064 346.3897838 0
3500 25.2 37.5 0.672096176 352.8504923 0
4000 31.6 45.0 0.701603402 368.341786 3
4500 38.2 52.9 0.722835631 379.4887065 8
5000 43.2 67.2 0.643229328 337.6953973 15
5500 49.3 80.9 0.608869347 319.6564073 19
WOT 62.2 132.5 0.469090339 246.2724282 21





NORTH
RPM GPS GPS GPH MPG RANGE TRIM
3000 18.2 28.3 0.643109541 337.6325088 0
3500 25 38.4 0.651041667 341.796875 0
4000 30.2 44.3 0.681715576 357.9006772 8
4500 38.1 54.5 0.699082569 367.0183486 15
5000 42.9 68.6 0.625364431 328.3163265 20
5500 48.6 81.5 0.596319018 313.0674847 24
6000 #DIV/0! #DIV/0! 27
WOT 61.2 133 0.460150376 241.5789474 31
SOUTH
RPM GPS GPS GPH MPG RANGE TRIM
3000 20.7 30.6 0.676470588 355.1470588 0
3500 25.3 36.5 0.693150685 363.9041096 0
4000 32.9 45.6 0.721491228 378.7828947 8
4500 38.3 51.3 0.746588694 391.9590643 15
5000 43.5 65.8 0.661094225 347.0744681 20
5500 49.9 80.3 0.621419676 326.24533 24
6000 #DIV/0! #DIV/0! 27
WOT 63.1 132 0.478030303 250.9659091 31

INTREPID PERFORMANCE REPORT


HULL NUMBER IBW43159G819

MODEL 430 Sport Yacht

PROPS Yamaha XTO 16 3/8" x 21P

ENGINES Yamaha 425hp

ENGINE HEIGHT P 4+6↓ C 4+6↓ S 4+6↓

CAV PLATE P 2 1/4" C 5 1/2" S 2 1/4"


NORTH RPM GPS SPEEDO GPH MPG TRIM
3000 20 N/A 27.7 0.722021661 0
3500 25.5 36.2 0.70441989 0
4000 36 46.7 0.770877944 1
4500 42.5 55.2 0.769927536 2
5000 48.5 71 0.683098592 4
5500 54.5 89.2 0.610986547 5
6100 60 114 0.526315789 6


SOUTH RPM GPS SPEEDO GPH MPG TRIM
3000 21 N/A 28.3 0.74204947 0
3500 28 34.1 0.82111437 0
4000 37.5 46.1 0.813449024 1
4500 44 57.7 0.762564991 2
5000 49.5 70.1 0.706134094 4
5500 55.5 87.2 0.63646789 5
6100 62 116.7 0.531276778 6

AVERAGE RPM GPS SPEEDO GPH MPG TRIM
CRUISE 4000 36.75 N/A 46.4 0.792025862 5
4500 43.25 N/A 56.45 0.766164748 5

TIME TO PLANE RPM

NO TABS 11.2 Seconds MAX RPM 6100
MAX
FULL TABS 8.8 Seconds RPM RANGE 5500-6000









Old 02-27-2021, 05:52 AM
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If 350 yams do the trick I'd be thinking about 350 zukes. Way less money than the other options and push big heavy hulls well. If you don't care about money I'd go 450 merc
Old 02-27-2021, 06:00 AM
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The 87 octane fuel that the 300 V8s require is much easier to find on the water (and cheaper) than the 89 octane that’s required by the Mercury 450Rs, Yamaha 425s or the Suzuki 350s.

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