Newbie looking for speed!!!

[deejay0071]

Ok my fellow boaters,

Just bought a Bayliner 174 ski and fish, and will be looking to pull skiiers while having approximately 4 other in the boat. Since I haven't even put it in the water yet besides a demo run, I'm not sure of what I am looking for. I know I will want to get up on the water fast and get some power quick with the weight of the family in the boat so my question for the masters are this:

1 - Is the the stock Alpha 1 with stock prop able to do what I am looking for? WOT is listed as 4400-4800 with a top speed of 38.5 ( I was told by the salesman it would do 48mph.

2 - What should I be looking at for a top speed with the stock prop and a weight of possibly 550 in the boat and 15 gallons of gas?

3 - Should I be looking at changing the prop for better start or top speed?

I want the boat to run quick but not have to struggle when pulling or getting water fun (Skiing and tubing) started.

Any help would be nice for this newbie...
\
Thanks to the masters and I look forward to your replies...

J

 

[HT32BSX115]

Re: Newbie - 3.0L mercruiser on 2011 174 Bayliner

Re: Newbie - 3.0L mercruiser on 2011 174 Bayliner

Howdy and Welcome aboard!

1 - Is the the stock Alpha 1 with stock prop able to do what I am looking for? WOT is listed as 4400-4800 with a top speed of 38.5 ( I was told by the salesman it would do 48mph.

Maybe. But probably not fully loaded

2 - What should I be looking at for a top speed with the stock prop and a weight of possibly 550 in the boat and 15 gallons of gas?

Probably less than the above. There's no easy way to predict it. Just take it out and try it!

3 - Should I be looking at changing the prop for better start or top speed?

NOT until you try it. This is usually a trial and error type of thing. You are starting out with a relatively low HP engine, you're not going to be able to get V-8 performance with a tiny 4 banger.

I want the boat to run quick but not have to struggle when pulling or getting water fun (Skiing and tubing) started.

Wait until you try it but you'll probably find that if you have 4 big adults in the boat and a 200 pounder on the end of a ski rope, it's not going to come out of the hole like it has a V-8 installed (because you don't have a V-8 installed)


In general, you should "prop" the drive so that it turns near the MAX RPM (4800 for yours) at Wide Open Throttle (WOT) When loaded near the weight you'll normally operate at the pressure altitude (elevation) you'll be using the boat. (for example, it's not going to operate the same if you go to 6000' Lake Tahoe)

I was told by the salesman it would do 48mph

They'll always say ANYTHING to get you to sign the contract!!


Regards,


Rick

 

[bobhol]

Re: Newbie - 3.0L mercruiser on 2011 174 Bayliner

Re: Newbie - 3.0L mercruiser on 2011 174 Bayliner

I have a 3.0 in my Chaparral 18 and I found that going to a 19 pitch from the 21 really helped for a hole shot .I pull skiers and wakeboarders with 3 and 4 in the boat just fine ...as for speed I can just break 40 mph at 4600 rpm on a good day...it may not have v8 power but it has 4 cylinder gas mileage which I appreciate ...regards,Bob

 

[98Shabah]

Re: Newbie - 3.0L mercruiser on 2011 174 Bayliner

Re: Newbie - 3.0L mercruiser on 2011 174 Bayliner

I'm guessing it's not going to do what you want without a different prop but the only way to know is to get it out and try it. I'll also go out on a limb here and say that it'll probably never do 48mph.. My 18' with the 3.0 does 38mph at 4600rpm with a 21" pitch aluminum 3 blade prop, family of 4 (2 kids) in the boat, full gas tank (30 gallons), with beach gear in the boat. Same load with me trying to get up on a wakeboard (165lbs) and it wouldn't plane or get over 15mph. I just bought a Solas Amita 4 blade aluminum prop to try (I bought it from iBoats actually,98 bucks!), I'm hoping it'll pop me up on the wakeboard now, though I know i'll be sacrificing a few MPH on the top end and may have to watch the RPMs if I run wide open.

 

[steelespike]

Re: Newbie - 3.0L mercruiser on 2011 174 Bayliner

Re: Newbie - 3.0L mercruiser on 2011 174 Bayliner

Your Fish and ski is no light weight at 1800 lbs.
48 is either uninformed or salesman talk.a 21" prop at 4800 produces about 43.Disreqerding load and hull form.
If you get around 40 gps Be very happy.As far as prop consideration get us base line details in " read this first" at the top of the prop forum.A light run and a typical load run will help a lot.
Trim down for hole shot trimming up as speed rises.
For water sports you may want some passengers forward at least till it planes.

 

[achris]

Re: Newbie looking for speed!!!

Pulling skiers and high top speed are opposite ends of the spectrum... Choose which one is the highest priority... There is no such thing as a 'stock' prop. Each boat/engine/application combination will need it's own prop.

What you need to do is get out on the water and see what it's doing (using a confirmed accurate tacho and a GPS), and use that as the baseline for any changes you make. Once you get the engine running in the 4400-4800 range (and I prefer to be at the top end of the range), for pulling skiers, change to a prop about 2" smaller in pitch. Also look at using a dedicated skiing prop, like a Laser II or a High 5.

Chris.......

 

[Bondo]

Re: Newbie looking for speed!!!

Ok my fellow boaters,

Just bought a Bayliner 174 ski and fish, and will be looking to pull skiiers while having approximately 4 other in the boat. Since I haven't even put it in the water yet besides a demo run, I'm not sure of what I am looking for. I know I will want to get up on the water fast and get some power quick with the weight of the family in the boat so my question for the masters are this:

1 - Is the the stock Alpha 1 with stock prop able to do what I am looking for? WOT is listed as 4400-4800 with a top speed of 38.5 ( I was told by the salesman it would do 48mph.

2 - What should I be looking at for a top speed with the stock prop and a weight of possibly 550 in the boat and 15 gallons of gas?

3 - Should I be looking at changing the prop for better start or top speed?

I want the boat to run quick but not have to struggle when pulling or getting water fun (Skiing and tubing) started.

Any help would be nice for this newbie...
\
Thanks to the masters and I look forward to your replies...

J

Ayuh,.... Yer gonna be disappointed,... Ya shoulda bought a Bigger boat, with a much bigger motor...

That's not even realistic...

 

[Circles47]

Re: Newbie looking for speed!!!

Don't get discouraged Deejay. There's really no way of knowing for sure until you get it on the water for some real numbers. If and when you do, this is what you need to post on here:

Max operating range of motor
RPM's at WOT (wide open throttle) and trimmed to boats "sweet spot"
MPH as per a GPS
Gearbox ratio
Diameter and pitch of current prop

With these hard numbers, we can give you a few more facts, but the end result will still be a bit of trial and error.

Actually, if you're running at 4800 rpm now, with a 21 inch pitch prop, with a gear ratio of 2.01, your max theoretical speed is 47.5 mph. Figure in boat weight, motor weight, ppl weight, and everything else weight.......your speed will only decrease. But get us some real numbers.

 

[deejay0071]

Re: Newbie looking for speed!!!

Much thanks for the responses my friends, and I look forward to breakin this boat in proper. I will be back on here after the summer and repost my findings.