How fast does your 4.3L V6 push your boat?

[jkust]

My 2003 18'3" Chap at 2900# dry weight, 190 HP, 33 gallons of fuel and 450 lbs of gear/people (3565 # total), windshield shut with bow cover on and 21 pitch aluminum marginal condition prop pushes 49mph gps at 4750 rpm. Not a speed demon but ok for the weight.

 

[md-lucky]

Re: How fast does your 4.3L V6 push your boat?

1987 Thundercraft, 18', 4 people with all our ski gear, open windshield, 1 person up front, 43mph on the speedometer.

We will have a GPS next trip to see if it is even close to accurate...

 

[QC]

Re: How fast does your 4.3L V6 push your boat?

Two of them push my friend's houseboat to 12 MPH . . . considering the weight I think that's pretty good Sorry couldn't help it.

 

[Pierutrus]

Re: How fast does your 4.3L V6 push your boat?

53 mph- GPS

 

[lkbum]

Re: How fast does your 4.3L V6 push your boat?

An interesting exercise is to calcualte the theoretical top speed of your boat (regardless of weight or HP). Take your max RPM, and divide it by the Gear ratio of the outdrive, this will give you the revolutions per minture your prop is turning. Then multiply this by the pitch of your prop, this will give you how many inches per minute you are traveling. Convert inches per minute to miles per hour and you will have the theoritcal top speed. I say theoretical because you will have prop slippage (you won't get the full pitch lenght in travel per prop revolution). Example calcualtion from my boat ...
4800 RPM / 1.62 Gear ratio = 2963 RPM at the prop
2963prop RPM X 19 inch prop pitch = 56296 Inches/minute (woo hoo baby)
56296 Inch/Minute = 53 Miles/hr
My Gps measures 49 Mph so I guess that pretty good prop performance.
My boat is a Chaparral 280 SSi with twin 5.0l EFI, but you can see from the calcualtions that it's not relevant. Speed will be dictated by RPM, Prop pitch (of course weight boat size etc dictate the HP and prop pitch to reach full RPM)

 

[Willyclay]

Re: How fast does your 4.3L V6 push your boat?

1995 Ebbtide 192SE (2600 lbs. empty) with 4.3LX 205HP (4 barrel carb) and 1.84 gears turning 21 aluminum prop at 4700RPM gets 48MPH by the speedometer. Will take the handheld GPS next time and cross-check!

 

[lkbum]

Re: How fast does your 4.3L V6 push your boat?

1995 Ebbtide 192SE (2600 lbs. empty) with 4.3LX 205HP (4 barrel carb) and 1.84 gears turning 21 aluminum prop at 4700RPM gets 48MPH by the speedometer. Will take the handheld GPS next time and cross-check!

Your theoritical top speed (see previous post) is just over 50mph, either your tach is reading a little low (you're actually turning higher than 4700rpm), your prop pitch is a little high or you've got a REALLY good prop.

 

[oops!]

Re: How fast does your 4.3L V6 push your boat?

any thing over 40 is great for a boat that heavy.....

id love 50.....

 

[tashasdaddy]

Re: How fast does your 4.3L V6 push your boat?

i think it is doing exactly what it is suppose to, you could play with trim and little. but you are in the right range.

 

[Tail_Gunner]

Re: How fast does your 4.3L V6 push your boat?

3200 lb Wellcraft..19' 4.3 GI 210hp 1.66 gearing 20p 4 blade stilletto 4900 rpm 55.1 GPS......90% of the time im at 3500 rpm and about 38 mph

 

[642mx]

Re: How fast does your 4.3L V6 push your boat?

My Islander 180 is powered by a 4.3L V6 (205 horse). I've been playing around with props and finally found one thats near perfect....

I'm running a 23 pitch Mercury Mirage Plus (thats right! a 23p and a V6!). WOT with 2 people and a near empty tank I can get 56 mph (GPS) at 4900 rpm. WOT full of gas with 4 people I can get 50 mph (GPS) at 4600 rpm. And it still takes off hard enough to pull my wife up on one ski. Its porpoising a little at WOT, so I'm going to have it labbed at BBlades this winter.

I had a Mirage 21 pitch and it would over-rev the engine at 5100 rpm at 51 mph. The 21 pitch is now my spare prop.

 

[lkbum]

Re: How fast does your 4.3L V6 push your boat?

My Islander 180 is powered by a 4.3L V6 (205 horse). I've been playing around with props and finally found one thats near perfect....

I'm running a 23 pitch Mercury Mirage Plus (thats right! a 23p and a V6!). WOT with 2 people and a near empty tank I can get 56 mph (GPS) at 4900 rpm. WOT full of gas with 4 people I can get 50 mph (GPS) at 4600 rpm. And it still takes off hard enough to pull my wife up on one ski. Its porpoising a little at WOT, so I'm going to have it labbed at BBlades this winter.

I had a Mirage 21 pitch and it would over-rev the engine at 5100 rpm at 51 mph. The 21 pitch is now my spare prop.

What did that do to your hole shot???

 

[642mx]

Re: How fast does your 4.3L V6 push your boat?

What did that do to your hole shot???

I lost maybe a second plaining out. Its not noticeable at all. My wife can't tell the difference when skiing.

I really thought it might have trouble taking off and was surprised when it didn't.... I don't know how many other boats with a 4.3 can turn a 23 pitch. Most dealers around here laughed when I asked about a 23p with the 4.3, but it works for me.

 

[sleeper]

Re: How fast does your 4.3L V6 push your boat?

I lost maybe a second plaining out. Its not noticeable at all. My wife can't tell the difference when skiing.

I really thought it might have trouble taking off and was surprised when it didn't.... I don't know how many other boats with a 4.3 can turn a 23 pitch. Most dealers around here laughed when I asked about a 23p with the 4.3, but it works for me.

My boat came with a 23p as the factory prop with the 1.81 gear ratio alpha? I switched to a 21p for watersports and I like it alot better. I also added smart tabs after the prop change, I might put the 23p back on and try it again. What is your gear ratio?

 

[sickwilly]

Re: How fast does your 4.3L V6 push your boat?

My 2004 Stingray, weight around 2500, with 1.81 gear ratio and its stock 23 pitch alum prop (and a SE Sport 300 hydrofoil) will just break 55 (speedo) with me in it.

I run a 20 pitch 4 blade most of the time, though, and with his I can only hit 48.

 

[fishingdan]

Re: How fast does your 4.3L V6 push your boat?

It is interesting reading about 23p props. I have a Cobia 198ES (19' 2" LOA) with a 4.3LX. The boat currently has a 4 blade 21p Solas prop and.....a stingray hyrdofoil (it was on the boat when I bought it). With a boat full of people, it is a great water sport boat for us. With less than 3 people in it, I can easily rev too high. Per my handheld GPS it is doing around 48 before I get too high with the rpms.

My plan is to remove the hydrofoil and record some numbers while running with the current setup. After that, I plan to install smart tabs and take numbers again. After that, I hope to properly prop this thing. This Cobia has a pretty shallow deadrise aft and once its up, it goes without much effort. I would expect mid 50s when done.

 

[carpaediem123]

Re: How fast does your 4.3L V6 push your boat?

I have a friend with a 2007 VIP 19' bowrider with the 4.3. She is running the factory, aluminum. 19P prop, and gives me hell all the time. She has to be getting around 50 as I have to run 52-54 to pass her. If she were to invest in a 21P SS prop, I have no doubt she could get mid 50's out of that boat.

 

[wca_tim]

Re: How fast does your 4.3L V6 push your boat?

18' checkmate bowrider, say 2300 pounds with motor, gas etc..., 60 - 61 with either a vented turbo 26" (4600 - 4700 rpms) or 23" laser2 (4700 - 4800 rpms). speeds gps.


I'll echo the above on the solas 4-blade 21. would run about 50 or 52 at arounr 4900 and maybe go faster if i let it, but was smooth and handling was great for water sports... also, hooked up out of the hole like nobody's business

 

[642mx]

Re: How fast does your 4.3L V6 push your boat?

My boat came with a 23p as the factory prop with the 1.81 gear ratio alpha? I switched to a 21p for watersports and I like it alot better. I also added smart tabs after the prop change, I might put the 23p back on and try it again. What is your gear ratio?

My gear ratio is the same as yours.... 1.81 on an Alpha 1.

I'm going to add some tabs too, but I think I'm going to put on electric tabs. I use the boat a lot on Kentucky lake and it gets real rough, so I think its what I need.

 

[mthieme]

Re: How fast does your 4.3L V6 push your boat?

'69 Searay with a Cobra I/O, 21P prop - 34 knots.
I tried a 19P prop Monday (because it was free and I wanted to see what would happen) - lost 3 knots at 3000rpm.
But the hole shot was better and she planed off quicker.