23 lancer inboard prop size

1cculpepper · Post by **1cculpepper** » Sat Jul 25, 2009 7:01 pm

Anyone know what the proper prop size is for our 1977 23' Lancer (tru) inboard. it currently has a 13x12x1. The previous owner said he guessed at the size. Its supposed to have max 4200 rpms but it easily goes over 5000 and at the cruising
rpm of 3200 we can only eek out about 17 mph

at 4200 rpms only about 22 mph.
Boat has a tunnel drive and plenty of room for larger prop.
Any suggestions.

Thanks Tom

Paul P · Post by **Paul P** » Mon May 17, 2010 9:36 am

With your motor being able to rev to 5000 its obvious you are under-propped. You should bring this down to around 4200 max.

Standard prop for this boat, with 1.5:1 gear reduction is 15" diameter with 16" pitch (cupped).

Regards, best, Paul

drrot · Post by **drrot** » Mon May 17, 2010 4:35 pm

Tom,
You didn't mention what power you had.

Paul P · Post by **Paul P** » Mon May 17, 2010 5:30 pm

Edited message here, because I want to delete some of my rambling and get to the accurate data. Jim Staib is correct, the 23 Lancer inboard used a 1.5:1 gear reduction and a 15X16 cupped RH prop. I believe the shafting was 1"

Regards, best,

Paul

drrot · Post by **drrot** » Mon May 17, 2010 5:56 pm

Paul,
That is why I asked. In the 1977 23' Lancer with a 350 a 15X16 wheel is called for. Seems to have a 1.5-1 reduction.

Paul P · Post by **Paul P** » Tue May 18, 2010 10:19 am

Hey thanks for being kind, I learn something every day!
It makes a lot of sense to put the slight reduction on that boat. Am interested in knowing more as I'm looking for one now.

Regards,

Paul

drrot · Post by **drrot** » Tue May 18, 2010 3:43 pm

Paul,
Seems they came in Straight inboard, called "Tunnel Drive"
I/O and Volvo drive. The latter 2 probably similar. A 225 Chrysler is even shown as a power option.

Paul P · Post by **Paul P** » Tue Aug 03, 2010 11:45 am

Hello guys,

EDIT NOTE (this is for a v-drive Commander, 1.0:1 and 300+ horsepower tweaked motor, the info is not appropriate for the inboard Lancer, which we subsequently discovered had a 15x16 prop and 1.5:1 gear reduction, verified off an original condition boat)
Here is some info I thought would be of benefit to the 23' Lancer contingent. This is from a 23' Commander with V-drive, with rebuilt motor now putting out just a bit over 300 horsepower.

Info below from my buddy Bill.......for what it's worth, in the name of sharing info!

"The original prop for a 23 Commander w/ 327 was 13 x 13 cupped.

Since my overhaul I have found that a 14 x 11 cupped is the way to go.

I turn that prop max at 4500 rpm. I am now running the original 13 x 13 (due to damaging the 14 x 11) and she spins out too high being able to hit 5000 and beyond. Not what I'd like, but I just keep the Rs to about 4K until I can get a new prop.

My prop of choice is a Michigan propeller DynaJet 14 x 11 cupped w/ 1 1/4" shaft."

River man · Post by **River man** » Sun Oct 31, 2010 5:55 pm

I know this is an older post but it brings to mind a concern. I have a 1977 23 Lancer inboard powered by a 350 K. I run a 15 x 16 prop as per the previous owners instructions. My concern is that my rpms top out at 3600 to 3700 yet my top speed is about 36. Shouldn't I get higher revs and thus higher top speed? Thanks

Paul P · Post by **Paul P** » Mon Nov 01, 2010 8:50 am

I have edited this note due to more info being available, and I want to be sure and give out good info to all my CC friends!

What transmission are you using? If you are using a 1.0:1 then the 15 X 16 would appear to be way too much prop for the boat. I just checked with a friend of mine (yes, I have friends) who has a 23 inboard and he said his is 1.0:1. He will confirm his prop size and I'll post it here for the record. If by chance you are using a 1.5:1 it may have been a change by CC or something that is a result of a motor swap out.

Previous notation indicates the stock Lancer 23 came with a 1.5:1 gear reduction (this is not confirmed info, beware, it could be incorrect), so that would make more sense to get up into the size you are noting, but if you can only reach 3700 rpm, you may be over-propped. I would not think your top speed is going to vary much, but it would be easier on the motor to be running with a little higher rpm and a little less pitch I would think . One way to find out, get a low cost spare from ebay and see what it will do!

Please confirm the transmission gear and the number of blades on your prop and we'll take it from there.

Regards,

Paul

Paul P · Post by **Paul P** » Wed Nov 03, 2010 1:03 pm

Well I finally have something to report. The reference to the 1.5:1 gear reduction is right on the money.

The 15 x 16 prop is also right on the money.

I have verified the hull card on one of these boats has a 3520 prop which is a 15x16 RH.

The Paragon transmission in that particular boat is P32-AR, which is a 1.5:1 gear reduction. That is the only way a motor this size could handle a 15x16 prop.

(This info is compliments of Paul Mathias, who took the time to go obtain this info from his 23 inboard. Thanks Paul, we all appreciate this.)

Calculating the pitch and rpm, at the 4000 rpm mark the prop is spinning 2666 rpm, and the pitch propells it 42,666 inches in per minute, equating to 40-miles per hour, deduct something like 12% for slippage and we're looking at 36-mph with this prop at 4,000 rpm engine speed. If the boat would run 4200 rpm then there is a little more speed potential. Of course, this is all on paper, and this may differ due to weight, hull configuration, etc., but it can be used as a guide.

The P series has a P 200, P 300 and P 400 model. The 200, 300, 400 part of the equation designates the gear size, which is not directly tied to the reduction, but more so the load capacity of the transmission.

The 1, 2, 3, 4, designation on a transmission correlates like so:

1 = direct drive
2 = 1.5:1
3 = 2.0:1
4 = 2.5:1

Therefore a P 34 would be the Paragon 300 series in a 2.5:1 gear reduction.

Regards,

Paul