Thoughts on what Propeller for an 18ft open bow

[QBhoy]

Hi
Just looking to see what others opinions are and what they run with and have tried on similar boats to mine.
I have an 18ft Campion Chase performance edition with a 5.0mpi mercruiser and corsa marine exhaust (few mods) attached to an Alpha 1 gen 2 1.47:1 ration.
I currently have a 19"P Laser 2 on her and she appears to go very well. I did have a 21p laser 2 but didn't think she ran as well, although I didn't maximise the trim perhaps as much as I do now....now that I know the boat.
I'd be really interested to see how other similar sized. boats run with similar set up and different props.
I was thinking about trying the tempest +, trophy +, high 5 (although I think this will certainly be slower), vengeance, enertia and perhaps the rev4 (although the bigger diameter worries me, regarding pitch selection).
So...anyone with a similar boat and a v6 or v8 engine...I would welcome their thoughts on this.
Thanks
Allan

 

[Sea Rider]

Each boat installation is unique, doesn't matter if both are same and sharing same HP engine, wot rpm along current passenger load is something to have in consideration when wanting to maximize props. Have not stated if current prop along current load makes engine to run middle to max wot rpm range. Let's start with that info.

Happy Boating

 

[Scott Danforth]

My 19' with 5.0/A1G2 had a 19p Solar on it and it was set up perfect. Could hit 50mph with just myself.

However as Sea Rider pointed out, each boat and it's loading is different.

What RPM are you running at WOT, what GPS verified MPH are you going at WOT, what issue are you trying to solve?

 

[jkust]

Hi
Just looking to see what others opinions are and what they run with and have tried on similar boats to mine.
I have an 18ft Campion Chase performance edition with a 5.0mpi mercruiser and corsa marine exhaust (few mods) attached to an Alpha 1 gen 2 1.47:1 ration.
I currently have a 19"P Laser 2 on her and she appears to go very well. I did have a 21p laser 2 but didn't think she ran as well, although I didn't maximise the trim perhaps as much as I do now....now that I know the boat.
I'd be really interested to see how other similar sized. boats run with similar set up and different props.
I was thinking about trying the tempest +, trophy +, high 5 (although I think this will certainly be slower), vengeance, enertia and perhaps the rev4 (although the bigger diameter worries me, regarding pitch selection).
So...anyone with a similar boat and a v6 or v8 engine...I would welcome their thoughts on this.
Thanks
Allan

How do you like that boat? Our local marina near our lake sold them for a few years but ultimately dropped the line completely as they had a lot of issues with them as well as the company. I like the looks of them as there are a few on our lake who bought them. It's tough with any given boat to compare to any other boat no matter if the engine and weights are similar. My previous boat was an 18 footer as well (different brand) but was undepowered for its weight where as it needed the 5.0mpi optional engine, it only got the 4.3 and you quickly ran out of steam (i.e. the rpm's and speed dropped) when you tried props with more complicated architecture. My current v8 seems to handle the most aggressive props with ease. It's amazing the extra torque you achieve with an extra two cylinders even in a small block.

 

[QBhoy]

Being honest, I've been around boats a long one and I can't imagine it running any better. It's probably pointless posting specs, because I am aware the propeller is probably ideal. Just perhaps interested to know what others are running and why. I have posted before regarding a similar subject and about this boat and regarding prop slip. I may have got the propellers mixed up that time. Here are the specs anyway;
With the camper canopy up (parachute);
RPM is around 5000rpm (rev range should be 4600-5000), although it's hard to look at dials when at that speed !
19p laser 2
Max speed gps is 58 mph (will run faster with canopy off).
In response to the latest, she is a great boat and handles well in a bit of a chop (for a North American boat). Sounds tremendous and beutifully trimmed. They are extremely rare across here in the U.K. And really stand out in terms of qualty over your average bayliner and similar. They were probably much dearer new though. As far as I know, there is only one of this spec across here.
Thanks

 

[QBhoy]

No Title

Lovely looking thing and flies when trimmed up.

 

[QBhoy]

Picture above was taken with a 21"p. Not sure of speed but it would be over 60 anyway.

 

[Sea Rider]

If running already at max 5K wot revs I would stay with that 19 prop as currently loaded, with a 21 pitch should achieve slight more top end speed along lower wot rpm & slight less fast hole shot compared to a 19 pitch.

Happy Boating

 

[QBhoy]

Sea rider,
You are spot on...just wasn't as happy with the 21 on it. Lugged a bit at cruising speed I like (around 19mph and 2200 rpm with 19") and was always worried when opening her up with all that power going through an alpha 1 under load. She will be running at around 300hp with the exhausts, cam shaft and the UK fuel. I'd imagine.
Thanks for the replies. Would still love to hear how the other props perform on this class of boat, but as you say, they are all different and I'd imagine there are few this size with such an engine.

 

[jimmbo]

I'm partial to the Mercury Enertia. Very good hole shot as well as very good top speed, and it grips the water like it's welded to it.

 

[rallyart]

Your performance and RPM range are great. The only reason I'd look at changing it would be to enhance hole shot and watersport use. If that is what you want, then I would put on a 4 blade with a vent system and stay at 19" pitch. That would increase your hole shot and control at below planing speeds without taking too much off the top end. I would avoid going with the High-5 or lowering pitch because I suspect that top speed matters to you.

 

[Sea Rider]

Testing other props when you already are running at the sweet max wot rpm range as usually loaded could turn into a costly adventure, will need to buy those mentioned props and test therir performance on water as opposed to trying them without having to buy them.

If wanting to better hole shot go for same diam prop with one less pitch, say an 18, full throttle, once on plane reduce throttle, Once there can cruise at the speed and rpm you like while maintaing good plane. Watch tach and throttlle bit less as a 18 pitch will overrev the engine when at wot.

Like maximizing props myself but always OEM ones as other brands, models, could turn into costly ones and be dumping money into the deep blue if not working as expected.

Happy Boating

 

[QBhoy]

Brilliant stuff guys
Not too bothered about hole shot to be honest. I never really open it up from standstill but when I have, the hole shot seems brisk enough. That said she has a wake tower which I might try out this year (if I'm feeling spritley enough to get back into that. If I do, I would buy a prop just for that.
I have a feeling I have the optimum prop on it for all round use...but we all chase the illusive I suppose !
I read about laser 2 props loosing grip on turns, but who turns more than a few degrees at high speed anyway....? I certainly don't have the need to. I just slow down a bit and trim the bow down a bit.
The enertia...I have wondered about that prop, but is doesn't look as viscious as the laser, rake wise ??
I'm wondering if there is a more top end orientated prop (within reason and excluding choppers) than the laser ? Tempest plus looks like the only contender ?
Thanks again.

 

[harleyman1975]

I run a 19 p 4 blade on mine and like it very much!

 

[Sea Rider]

Can't achieve better top end speed along best hole shot worlds in one single prop as one opposes the other, unless you run a variable pitch prop on that engine.

One thing is boating lightly to medium loaded, other fully loaded. I guess that if boating lightly to medium loaded, don't need to be that prop exquisite as standard delivered OEM props performs pretty well.

I'm totaly in agreement about chasing the ilusive boating perfection, but to some extend as long it's not a costly trial with no avail that you'll regret later. LOL!!

Happy Boating

 

[jkust]

Sea rider,
You are spot on...just wasn't as happy with the 21 on it. Lugged a bit at cruising speed I like (around 19mph and 2200 rpm with 19") and was always worried when opening her up with all that power going through an alpha 1 under load. She will be running at around 300hp with the exhausts, cam shaft and the UK fuel. I'd imagine.
Thanks for the replies. Would still love to hear how the other props perform on this class of boat, but as you say, they are all different and I'd imagine there are few this size with such an engine.

That's a great looking boat. I wonder what the actual hp is? Open exhaust adds very little HP to a small block V8 and the cam swap aggressiveness/ HP increase would be limited by reversion possibilities and higher octane fuel does nothing at all unless the compression called for it. I just don't know anybody that has really modded their MPI engine like you so I'm really curious.

If it is 300, which is the same as my 5.7 mpi, I run a 17 Inch Mirage Plus with the holes plugged. Excellent hole shot and 54+mph GPS loaded with 60 gallons in the gas tank and 4 passengers. A bit faster with less gas and a couple less passengers. The Mirage is a bit aggressive so robs me of a bit of top end rpm's.
Generally satisfied with mid 50's since I only hammer it every now and again but do like the quick hole shot which I notice more often.

 

[QBhoy]

Hi jkust

I'm not certain of the exact horse power to be honest. It's an educated guess.
I agree that normally an exhaust like this may not have much of a difference on a small block, but add a cam and I can certainly guarantee it does. She seems easier and has much less resistance or back pressure from the water with the corsa marine exhaust. This came fitted from the factory. Not many of them were made like this apparently.
As for the octane rating. It's certain that the higher the octane, the more horse power you will gain. It may be small numbers, but there is certainly a gain. There are many documented tests proving this. There is always a difference in the hp output of the same cars sold in the us, in comparison to the uk. Cars with the same engine will always dyno higher in the U.K. On regular petrol, than the US regular petrol/gas.
Like I say, not sure about the increase, but the cam alone is thought to add 25-30hp minimum...apparently.
Your boat sounds like a lovely one And doing really well to get that sort of speed with the size, weight, prop and assumed gear ratio. Good stuff !