Bought a Laser 2 for 5.0MPI, mistake??

[rbezdon]

I have a 2003 Caravelle Intercepter 212SS with a MercCruiser 5.0MPI alpha 1 Gen 2 - 260HP. the dry weight is around 2900lbs. The Interceptor is more of a Sportboat hull than a typical bowrider. I typically turn 5200 RPM and even occasionally hit the rev limiter at (audible alert) around 5300 to 5400 RPM. I an running the original MercCruiser 14 1/4x 21P aluminum prop and running with 4 adult men, moderate gear and a full tank. Speed is roughly 51MPH based on the boat speedo, not GPS. The hole shot is OK but not great. I put these numbers into the Merccruiser prop selector and it recommended several Stainless 14 (roughly as all are around 14)x23 options The "details" button on their calcualtor says ideal pitch is just over 22 and top speed should be over 60. Based on this I have ordered a Laser II 13 7/8 x 23 which was the first recommendation. Their calculator doesn't accont for the aluminum to SS conversion anywhere I can see. Did I make a mistake??

 

[Robbabob]

Re: Bought a Laser 2 for 5.0MPI, mistake??

Since you already purchased it, might as well test it.

Seems to me, with the necessary rpm reduction your engine needs, what you think is a mistake could be spot on for your needs.

 

[bwady]

Re: Bought a Laser 2 for 5.0MPI, mistake??

I have a 2003 Caravelle Intercepter 212SS with a MercCruiser 5.0MPI alpha 1 Gen 2 - 260HP. the dry weight is around 2900lbs. The Interceptor is more of a Sportboat hull than a typical bowrider. I typically turn 5200 RPM and even occasionally hit the rev limiter at (audible alert) around 5300 to 5400 RPM. I an running the original MercCruiser 14 1/4x 21P aluminum prop and running with 4 adult men, moderate gear and a full tank. Speed is roughly 51MPH based on the boat speedo, not GPS. The hole shot is OK but not great. I put these numbers into the Merccruiser prop selector and it recommended several Stainless 14 (roughly as all are around 14)x23 options The "details" button on their calcualtor says ideal pitch is just over 22 and top speed should be over 60. Based on this I have ordered a Laser II 13 7/8 x 23 which was the first recommendation. Their calculator doesn't accont for the aluminum to SS conversion anywhere I can see. Did I make a mistake??

Read my post below yours.. on the Baja with 5.0 mpi.. I made the same mistake you did. Send it back if you can.

 

[rbezdon]

Re: Bought a Laser 2 for 5.0MPI, mistake??

BWADY - shipped today so to late and in fact reading your post is what prompted me to post this thread. I am hoping since the hull design between your boat and mine is quite a bit different, that Rob is right. Guess I can always try to resell on eBay. I found a 22P version after and I am tempted to buy it and then sell the poorer perfroming of the two. What concerned me though is the general comment that the Laser 2 is better on OBs and not good for Stern drives.

Also, as for hole shot, I am willing to consider trim tabs or the Hydro Foil type fin. I had one on my old 5.0 carb OMC Bayliner and it helped alot.

 

[Tail_Gunner]

Re: Bought a Laser 2 for 5.0MPI, mistake??

A few things..I am assuming your engine is a efi unit and if so you have a built in rev limiter that caps your rpm at 4950..Indicating your tach is off...Give merc a call with the serial number from the engine and they can tell you where your rev limiter is set.

Doing that you be able to make a much better selection in a prop that is knowing your rpm and true gps speed..Seems annoying but props are expensive and there can be quite a difference between a well setup boat and one thats so so....

Whale tails actually hinder performance stay away from them if you can.

 

[emilsr]

Re: Bought a Laser 2 for 5.0MPI, mistake??

Check your speedo with a handheld GPS. You're probably running a little faster than you think....at least you should be with that engine/hull if it's trimmed properly and nobody is sitting in the bow.

 

[rbezdon]

Re: Bought a Laser 2 for 5.0MPI, mistake??

Thanks for the info guys. Its Father's Day and so I get to go out Sunday (assuming the weather holds). I have another tack and a GPS from te old boat. I'll take it with and try to confirm.

 

[rbezdon]

Re: Bought a Laser 2 for 5.0MPI, mistake??

Did a bit more testing over the week end and found out the boat tach may be off by 100RPM or so but it is pretty close. I also found out during testing that the revlimiter is set between 5300 and 5400RPM. During a couple of hard runs with 6 heavy adults and coolers etc I cavitated the prop by over trimming and sharp turns and at about 5300+ the RPMs hold and I get a sound alert. Even with the big load I can hit 5100 to 5200 RPM. speed in the low 50S. Obviously, since I bought the prop I'll try it and hope the hole shot/towing is still OK. We will see. If not I'll have to go back to a 21P of some kind.