Prop for 1977 18SF with Suzuki 140

[pjzabo]

Finishing up my 1977 18 SF rebuild. Replaced and raised the transom, new 44 gal tank. Going ping pong scuppers, hinged splashboard and floor drain holes into the bilge and drain holes in the splashboard out the stern.

Just sea trailed her for the first time today with a 3 blade 14/20 prop. Definitely rips - couldn't see the handheld gps cause I was tearing too much (was 50 degrees when I got out). Bow seems very high as she comes on plane. Gonna need to lose weight or move weight forward further (I have 2 batteries as far forward in the console and mounted the new gas tank as far forward as possible).

Would appreciate prop suggestions for my setup. I am not going to raise the floor, but I might move the console a little further up and go with a light leaning post.

Thanks - Pete

http://i978.photobucket.com/albums/a...g?t=1289609262

[McGillicuddy]

Cant wait to see more of your new rig. Looks great!
115 or 140?
RPM at WOT?
Trim tabs or not? If you don't have them I'd put em on the Christmas list.
Style or name of prop?

It may be as simple as changing the prop.
If you have a speed prop that gives good bow lift that may be your problem. I would find out what the biggest diameter your motor will swing and move to that diameter reducing pitch if necessary. With big round Mickey Mouse ear blades and vents. That will get the rear end up forcing the pointy end down and thus help you plane evenly and quickly. A 4 Blade would also help your overall cause. Both will help hole shot and economy. If your boat is on a trailer it might be helpful to post pictures of it from behind the transom and the side at the transom with the motor down. Unles you already have some pics shoot the foto at the cavitation plate level.

When you get that rig dialed in I think it will be incredible! I've heard some say that in slop the 18 rides better than the 20 (that ought get you some responses hopefully not derailing your thread)

[pjzabo]

OK - took her for a good spin today (and 4 keeper Blackfish). With 3 big guys on board (660 lbs) and fishing gear and 1/2 full 44 gal tank we hit 43 mph at 6000 rpm. The 14 inch wheel seems the largest that the Suzuki 140 will take. This prop is 3 blade stainless and 20 pitch. With the three of us on board it was a but of a sky shot when hammering it to get on plane, after about 5 seconds it came down, squatted into the water and frikin took off! At 4500 rpm I was still running 29-30 knots into a slight chop on the long island sound.

I'll post many more pics in the coming week. Awesome boat!!

[strick]

OK - With the three of us on board it was a but of a sky shot when hammering it to get on plane, after about 5 seconds it came down,

I've been told that with the 140 it is best to have a 4 blade prop if you are going to fish with more then 2 guys on board.

strick

[McGillicuddy]

Pete,
Do you have trim tabs?
For some reason I thought th Zukes would take a bigger prop, but biggest stuff I saw was 14" like you said. Your rpms are perfect, but it really sounds like to have a bow lifting prop.

Where were your buddies situated on take off? Until you get a 4 blade prop, better put 2 riders in front of the console and wrap'em up in Grundens

p.s. Nice work on the 'togs!

[Bushwacker]

You're stern heavy for sure with that motor, so you definitely need a good stern lifting 4 blade prop and maybe a doelfin or equivalent on cavitation plate. What is your min planing speed? With trim tabs, the right prop, and CG in design location, you should be able to plane at 12-13 mph.

[pjzabo]

I had one guy in front of the console and another next to me. We are both 6'2" between 230-240 lbs, lots of weight in the back fer sure. I will typically only be fishing 2 in the boat, me at the helm and the other guy in front of the console. I was thinking about a doelfin and maybe moving the console up about 5 inches from its stock location and going with a small leaning post to replace the stock seat. I want to avoid putting on trim tabs. Next weekend I will take a bunch of pictures and better observations on planning speed, time to plane, etc. It looks like the 14 inch wheel is the biggest that fits on the 140. Aside from the unnerving bow high shot when you first get on her and the delay until it squats down on plane, the performance of this 3 blade 14/20 is pretty good. I can pull 6000 rpms matted and even at 4500 I am cruising 28-29 knots. I will mix up the engine speed more to see how it behaves and report back.

[McGillicuddy]

Aha! Suspicions confirmed! No trim tabs.
Next to that sweet motor, trim tabs would be your greatest asset. I understand not wanting to drill any holes in your boat so I'll leave that alone now.

A 4 blade will help lower your minimum planing speed and get the pointy end down much quicker.

As Denny mentioned, for less than $50 you can get a planing foil. SE Sport makes a foil that doesn't require 4 holes in the anti-cavitation plate. http://www.amazon.com/SESport-SPORT-.../dp/B002HW3IJO
If that solves the problem great. If not, they are an easy resale on CL or whatever.

I had one on my Seafari and was pleased with its effect. I took mine off because when I dropped to a 15p stern lifting Black Max, my hole-shot to plane became virtually instantaneous. Of course my motor is a 300 lb Merc 115 and my CG is farther forward.

[uncleboo]

Howdy! I'm swinging a 21 pitch 3-blade. I'll have to check dia. I usually run with my wife and daughter or me and a stout friend. Usually about 400-450 lbs. with a full 44 gal tank. Moved my batteries under the console and put a Todd mini pedestal mount leaning post.

My bow doesn't skyrocket, but tabs would certainly help. I'm getting 41 mph @ 5800 rpms trimmed out. My mechanic told me not to let it go over 6000, so, I don't. Can't remember rpms at cruise, but then, I'm all over the place. I like to go fast, when conditions allow. When it's choopy, I just cruise at whatever is the smoothest.

[eggsuckindog]

another solution would be negitive trim spacers called wedges - just aluminum blocks about $35 and they give you more negative trim - worked fine on my boat before this.

Prop seems perfect by the way - I think 6K is about correct?