New member with some questions

C

Chiefsurfer

New member
Hey there guys. I bought a 1987 Wellcraft V20 last year. Boat came with a 1999 C150 yamaha(commercial), with what I believe is a 19" stainless prop. Great boat the few times i was able to get out on it, while trying to get all the work done I want.

When i went out last summer, I was getting ROUGHLY 40 mph, WOT, at only 5000 rpm. It's plenty of speed for me, as I can rarely actually take the conditions at that speed. I just know that the optimal fuel burn and performance is at reccomended WOT, which for this motor is 5000-5500. That was half tank of gas, lightly loaded. I am thinking I can maybe go to a 16" 4-blade, pick up the 300 rpm or so, and get a little faster plane.

Is 40 mph, at 5000 what you guys have found with a carb'd 150. People with yamaha's would be great, but realistically, if you guys are getting between 38 and 43, with your 150's at 5,000 rpm I think im in the range.

Oh, and glad to be here!!
 
Welcome Chief...my experience has been a 15 to 15 1/2" dia x 17 P prop will deliver best performance and fuel efficiency on a 150 HP...and try to make it a stainless prop if the boat budget allows

post up some pics of your V when you get a chance...we likey V20 porn...:clap:
 
reelapeelin said:
Welcome Chief...my experience has been a 15 to 15 1/2" dia x 17 P prop will deliver best performance and fuel efficiency on a 150 HP...and try to make it a stainless prop if the boat budget allows

post up some pics of your V when you get a chance...we likey V20 porn...:clap:
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X2 I second what Reel said... Also, not sure if a 4 blade will get you higher revs.. I think the opposite is true... It gets you a faster hole shot for sure.. but I think you lose at top end... I could be wrong.. I might have my figures backwards. But in all cases a 3 blade SS 17p should be just about gravy for that engine. Oh...and welcome to the site :hi:
 
Destroyer said:
X2 I second what Reel said... Also, not sure if a 4 blade will get you higher revs.. I think the opposite is true... It gets you a faster hole shot for sure.. but I think you lose at top end... I could be wrong.. I might have my figures backwards. But in all cases a 3 blade SS 17p should be just about gravy for that engine. Oh...and welcome to the site :hi:
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Destroyer, yer right on the money re the 4 blade prop...better hole shot, shaves a little off the top...also has stern-lifting tendency which would not be a bad thing for a V20...
 
i hav a 17P prop on mine and th that's EXACTLY the performance I get with my 1986 150 Yamaha.....40 mph at 5000 rpm... I've thought about monkeyin with the prop to get closer to 5500 rpm at WOT and see what I get but not really on my priority list....also figured being an 86 that it just might be a little too tired to spin up to 5500.
 
Thanks guys, I will have a closer look today. Sadly, there is no size stamped into the prop, where a size should be, there is just a number and letter stamped into the side of the prop housing.

I will post a few pics once I get her all done. Just painted the hull sides with medium blue brightsides. After about 25 hours of sanding the old tired gelcoat. I am going to do touch-up bottom paint to re-establish my water-line, and once it looks "perty" i will post pics. Also will be doing a good wash inside and out, will post pics then too.

Well if you guys say a 17 3-blade, i was thinking of going with a 15 4-blade. I know when you go from a 3 to 4, you want to drop your pitch 1-2" to keep your RPM pretty close to the same spot. I will have to go see what prop i got on her.
 
Chiefsurfer said:
Thanks guys, I will have a closer look today. Sadly, there is no size stamped into the prop, where a size should be, there is just a number and letter stamped into the side of the prop housing.

I will post a few pics once I get her all done. Just painted the hull sides with medium blue brightsides. After about 25 hours of sanding the old tired gelcoat. I am going to do touch-up bottom paint to re-establish my water-line, and once it looks "perty" i will post pics. Also will be doing a good wash inside and out, will post pics then too.

Well if you guys say a 17 3-blade, i was thinking of going with a 15 4-blade. I know when you go from a 3 to 4, you want to drop your pitch 1-2" to keep your RPM pretty close to the same spot. I will have to go see what prop i got on her.
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Sounds like a Michigan Wheel. Look at the front of the prop hub.. next to the thrust washer. Should be a couple of letters and numbers stamped into the metal right next to the splines.

You're right on the money about droppng your pitch on the 4 blade. That extra blade gives you a lot more thrust at your bottom end.. but it also takes more power for your engine to spin it, so you lose a little at your top end. In fact, the fastest prop for top end is a 2 blade, but you run into vibration problems with them. For our kind of recreational boating 3 blades is about right for most people. :beer:
 
Yeah, I don't care about losing the top-end, so long as it's not straining the motor any more. I think the added sternlift will be a good thing(i am already having a LITTLE trouble trimming down), and I am much more interested in quick on plane, over top speed.

I can do about 30 mph, at 3900, which is a PERFECT cruise for me in most conditions.
 
Welcome to the site by the way Chiefsurfer.....if you want a center console to aspire to following is a picture of our resident primo center console. Hopefully not offending any other center console owners but having seen it in person it is the baddest. (if that's a word)

017-2.jpg
 
Yeah it's almost hard to believe that boat started out life as a typical notched transom...Vic crafted that transom as you see it here and did all srt of additional fiberglass work...
DSCN0378.jpg

and it ain't JUST purdy...it's FAST!!...:clap:
 
here's some photos guys.

Really happy with the color, although i bought the "short nap" standard rollers that interlux reccomends, and the roller started falling apart almost immediately. Basically, gotta sand it down again and do it again, but for now I am happy.
 

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Thanks for the plug Reel. Welcome aboard Chiefsurfer. As a fellow center console owner I can say yours looks great in blue. I love Builder FL's center console, maybe my favorite, next would be Ben Fishin with his tower boat. I wish I had pics of my RueGoldberg molds I made for the rebuild.

The info on the 4-blade given here is spot on. Normally you move down in pitch a notch to get the same RPM. If you go that way try one before you buy it.
 
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