Help setup Piranha Espada 4,80 m with johnson 175 v6

[Flabenk69]

[ATTACH]name gero and I'm Italian, I'm very sorry for the wrong English!So I present to you my boat a Piranha Espada of 1988 of 4, 80m with a johnson 175hp v6 60 degrees with the 150 hp carburettor and propeller pitch 19 original aluminum omc!
the boat has an incredible set but the maximum speed does not satisfy me at all!
but since I am in this forum I feel with you, this is a small problem!!
the boat gets to 46 mph at 5600 rpm with 19 omc aluminum propeller (in the photo)
and a steel propeller pitch 18 arrives at 50 mph at 5800 rpm!


is not it a bit too slow??


I will! and I want to make sure to get her to at least 75 mph


do you think making the right changes can I get the speed you want from me with this engine????


if yes, what should I change??


if not I have a mercury 2.5 efi


PLEASE HELP ME I AM IN YOUR HANDS

[Skoontz]

Piranha, though I am not familiar with you exact boat brand but let me tell you that it looks like a splash ( copy) of a boat that was very popular in the US in the 70's/80's called the Sidewinder.

The Sidewinder was one of if not the first manufacturer to patent it's design with the high sides, hard transition deck lines and wrap around windshield. As others saw the popularity of the style numerous versions came out from a multitude of manufacturers. Sidewinder eventually filed a lawsuit to enforce the patent against someone, (I forgot who) and the copies disappeared about as fast as they came.

Why is this significant to your question?

Simple. The only boat I could compare yours to is the Sidewinder, 5 of which ran on the same section of river I ran my Switzercraft with a 99 cubic inch V-4 OMC. Assuming the bottom and weights are similar to the Sidewinder, 3 of the guys running on the river had OMC V-6's that were a bit older than yours. One guy with a 235 under a 175 cover hit 80 with a 28" Mercury Chopper prop that Don Hendrich (prop guru) had reworked but the boat was squirellier than a 3 pecker billy goat. We ended up helping him ad dual Ride Guide steering ( one cable pushing the other pulling from each side of the boat) and solid motor mounts.

On most days, any Vee bottom boat under 17.5' with a 99 cubic inch engine either a V-4 OMC or a big Merc in line grain silo ran nearly as fast on 1/3 less fuel consumption. What seemed to work better for the V-6 motors is when the manufacturers realized people wanted to step up in engine size and added 8" to a foot to their designs which essentially made them faster because they were more stable and the weight ratios balanced out better than with the smaller boats..

If I read your measurement correctly you said 4.8 meters correct? That is 15.75 American feet. The boat looks longer than that, but if your measurement is really 15.75 feet (4.80 meters) you got too much motor and weight to get your boat to 75 without spending a bunch of money.

We sat on the shore one day doing some calculations and figured a boat/motor/trailer in 1979 that would run 70 would cost you $6,000. If you wanted to go 72, you would spend an additional $300 on the right prop, assuming you got lucky and bought the right prop to get the job done. If you wanted to go 75 miles an hour, you would spend an additional $1,000. Each mile an hour over you wanted to go over 75 would cost $700-$1,000 per mile an hour. The calculations assumed you were buying new stuff and having a shop do your work.

You have a beautiful boat. I always loved the originality of that design.

[Flabenk69]

I thank you for rispota!
I sincerely quest for summer I thought these changes

-power hydraulic lift
-carburetor jets + 175hp
-helix srx 25 omc
Attachment 53388


do you think that with these changes will have improvements?

[Skoontz]

If the engine runs well as it presently is leave it be for the time being. You will be amazed at how much you can gain by getting the boat to lift from the water with a good propeller. That 17" aluminum that you have will propel move the boat, you want to "lift" the boat. When you are dialed in well, there should be about a 3" long by 3" wide piece at the bottom your boat will ride on. It will appear like it is flying. As you lift it from the water, you will need a few safety devices like a foot throttle and trim switches mounted on the steering wheel so you can keep both hands on the wheel. Shoot low but aim higher. Shoot for 70 MPH to use as a benchmark. If you get more its a double win.

When you say power lift do you mean a lift to jack the engine straight up and down from the water, or do you mean a hydraulic lift that changes the angle of the propeller shaft to the boats bottom? Power trim is essential to get bow lifted optimally and retain control.

Jacking the motor you can really do without and make those changes manually. I ran the best with the bottom water inlet of the gear case right at the boats bottom. This placed the prop shaft about 3-4" below the bottom. If I wanted to ad a nosecone with low water pickups I could have done more, but chose not to.
You will only be able to lift or jack the engine so far until you move the water outlets out of the water because the engine is going to overheat.

As for propellers, I always had better luck gaining bow lift on a Vee hull with a Mercury chopper propeller that we re-splined to fit an OMC. Ron Hill can probably set you up with about any propeller you need and most likely has a better recommendation, but I tried elephant ear props, cleavers, and choppers. The Chopper always got the job done better for my applications.

[Flabenk69]

Attachment 53389

i have only this pix of boat in water!

I'm sorry but I do not understand English very well and I did not understand that changes do! = (
So do not buy the power lift, but a bracket that do you think?

distance the motor from the stern 22 inch what do you think??

propeller and a chopper that step??

[Skoontz]

The attachment won't open. Dont worry about the English/Italian My Italian is pretty bad as well, have not used it since 1988 so bear with me here. .Non ho usato il mio italiano a partire dal 1988 in modo pelase portare con me.

La staffa si sta parlando è un cantilever. Ho avuto uno sulla mia barca più un 9 "taglio passo verso il basso. Il lato positivo di un cantilever che è la leva del guadagno Weill che alzerà l'arco. Il lato negativo è che sarà posto un sacco di stres sullo specchio di poppa. Ho anche visto con un bullone grande filettato in cima secolo che è possibile attivare per alzare ed abbassare il motore come meglio credi. Puoi anche fare una ad ottenere 4 pezzi da 1/2 "x 4" "in alluminio x4 e fori in un linea ogni centimetro per consentire al motore di aumentare di 1 "incrementi. avevo ancora i miei migliori risultati utilizzando un propulsore elicottero. hanno lame sottili lungo irregolari. vedete il filo comune qui? Se si vuole aumentare è necessario per ottenere il fondo bot fuori dall'acqua.

I hope this better explains what you are asking.

[Flabenk69]

I thank you very much for your time!
then will arrange modifying the transom and stretching of 60 cm!
with a surface propeller step 23!

I hope to spend at least 65 knots!

[Skoontz]

Molto bene. Sono confuso Piranha.

Si desidera eseguire un 23 "un'elica emersione? Ora abbiamo bisogno di un guru elica di intervenire ma permettetemi di approfondire qui. Mia comprensione di un'elica emersione è che si deve ottenere il più vicino alla superficie delle acque il più possibile. Quando mia figlia passò la ydroplane per esempio, vi era solo una lama piena dell'elica in acqua in acqua e per fare che l'albero di trasmissione è impostato 1 3/8 "sotto il fondo barche. Questo motore aveva una centralina con fori di aspirazione dell'acqua nella parte inferiore della scatola ingranaggi quindi erano sempre in lui l'acqua. Se alzi il motore abbastanza alto per un'elica emersione al lavoro, le prese d'acqua sulla centralina sarà troppo fuori dall'acqua per prendere l'acqua che raffredda il motore. L'altra cosa è una carena a forma di V, non penso che si sta andando abbastanza guadagno tpo sollevamento della prua per aumentare la velocità che stai cercando. È per questo che mi sento di raccomandare l'elica "Chopper".

[Flabenk69]

si ma dove trovo una chopper per evinrude / johnson v6 con 15 spline????????

ho cercato su internet e ho trovato in america per il mio motore soltanto un omc 25 srx (quella del post precedente) e in italia ho trovato soltanto questa http://www.subito.it/nautica/elica-b...302.htm?last=1 (una radu passo 23 di superficie)

ditemi voi dove posso trovare una chopper che monti nel mio motore??

[Bill Van Steenwyk]

The attachment won't open. Dont worry about the English/Italian My Italian is pretty bad as well, have not used it since 1988 so bear with me here. .Non ho usato il mio italiano a partire dal 1988 in modo pelase portare con me.

La staffa si sta parlando è un cantilever. Ho avuto uno sulla mia barca più un 9 "taglio passo verso il basso. Il lato positivo di un cantilever che è la leva del guadagno Weill che alzerà l'arco. Il lato negativo è che sarà posto un sacco di stres sullo specchio di poppa. Ho anche visto con un bullone grande filettato in cima secolo che è possibile attivare per alzare ed abbassare il motore come meglio credi. Puoi anche fare una ad ottenere 4 pezzi da 1/2 "x 4" "in alluminio x4 e fori in un linea ogni centimetro per consentire al motore di aumentare di 1 "incrementi. avevo ancora i miei migliori risultati utilizzando un propulsore elicottero. hanno lame sottili lungo irregolari. vedete il filo comune qui? Se si vuole aumentare è necessario per ottenere il fondo bot fuori dall'acqua.

I hope this better explains what you are asking.

WOW!!!!!

I never would have imagined a former recycler of disposed valuables turned landscape architect turned brewer (and who knows what else) would also be fluent in Italian. As that famous radio program from yesteryear used to announce, ONLY THE SHADOW KNOWS.

In all seriousness Bill, I am sure he appreciates your being able to help him in his native language. Very easy to misunderstand when trying to translate something to your native language, especially where an expenditure of dollars is concerned, or is that Lira? By the way how did the prop work for your daughter?