Prop Selection

D

Duke01

Member
Hello all...I am a new owner of a 1978 V20 Steplift Cuddy with a 1980 200 HP Mercury outboard. The existing 3 blade prop (48-78120-18) is banged up a bit so I am looking for a replacement. Does it make sense to consider a stainless 3 blade, or 4 blade? Top speed according to the old owner was 43 mph.

I am from MI and plan on walleye fishing in Lake Erie and Lake Huron.

I would appreciate input from the group...obviously a lot of knowledge here.

Thanks, Duke
 
Your current prop crosses over to a entry level, 3 blade, 18 pitch aluminum prop. Most any 3 blade cheap stainless prop in a 17 pitch would be a good choice for that engine to start with. Anytime you change props, even to a prop of the same part number, you can change your wide open RPM's or top speed.

I've had good luck with Solas props in the past. For a good all around prop they do pretty good, so far all of them I've run have run smooth, and they're cheap. A 17 pitch in the 13 1/2" to 14" diameter and 3 blades would be a good all round prop.

Larger diameter props have there pros and cons, but the larger diameter normally gives decreased prop slippage so much so you have to step down in pitch to keep your wide open throttle rpm's up. 4 blades give reduced prop slippage, normally provide better cruise speeds at a given rpm, but you normally(but not always) lose some top end speed(but some boats see an increase because the prop just works better with the boat).

Propping is an artform mixxed with some guessing, and some voodoo to get what you're after. What is ideal for one person may not work for another in the same boat. All you can do is try props until you find the one that works the best, and hope you do it in as few tries as possible.
 
Only thing I would add is, try working with a local merc dealer or prop shop. Most have a good idea where to start and will let u try some out before buying, like trying on shoes.

Also,let them recondition old one for a spare

Welcome to the cult, new guy buys lunch
 
phatdaddy said:
Only thing I would add is, try working with a local merc dealer or prop shop. Most have a good idea where to start and will let u try some out before buying, like trying on shoes.

Also,let them recondition old one for a spare

Welcome to the cult, new guy buys lunch
Click to expand...
Most any good prop shop will also do this. Admiral c&b used to swap me out for no charge so long as I brought the prop back in new condition. I know general propeller in Sarasota also has some good exchange policies, they will also repitch the prop for you for free if it's close and only needs a minor tweek.
 
Thanks guys, I truly appreciate the guidance. Step one will be starting the outboard in the spring. When I purchased the boat the motor had already been winterized. I will then follow-up with a prop purchase.

Lots of projects to do before walleye season (June, July, August...)
 
I have a 78 with a 200 Johnson on it. 43 seems a little slow. You might want to weigh your boat and compare it to the original specs. (allow for any gas in the tank) Waterlogged foam can add a considerable amount of weight and slow your boat accordingly.

As to the props, what TheFermanator said is good advice. Just remember if switching to a SS prop that SS flexes less than Alum, so normally you move down a pitch or two when switching. (So a 17P Alum becomes a 16P SS).
 
Destroyer said:
I have a 78 with a 200 Johnson on it. 43 seems a little slow. You might want to weigh your boat and compare it to the original specs. (allow for any gas in the tank) Waterlogged foam can add a considerable amount of weight and slow your boat accordingly.

As to the props, what TheFermanator said is good advice. Just remember if switching to a SS prop that SS flexes less than Alum, so normally you move down a pitch or two when switching. (So a 17P Alum becomes a 16P SS).
Click to expand...

His current prop is an OLD MERCURY 3 blade 18 pitch aluminum, I would expect a 2-5 mph increase in speed with most any decent stainless prop over an old tech aluminum. Aluminum has gotten better through the years, but his aint one of the better ones.
 
Thanks Destroyer and Thefermanator...the existing prop has a bent blade and a another blade with a chip in it, so that might explain the reported max speed of 43 from the previous owner. I suspect that the speed was recorded from the dash speedometer. I am curious to see what the impact of a new prop will be and will follow-up in the summer after launch. I will note GPS speed measurements.

Regarding the weight, the brochures call out a weight of 1920 lbs, with an associated max hp of 200. Not sure how accurate that is (?). In 1989 and thereafter, the brochures noted a weight of 2300, with and an increase in max hp to 235 (if I remember correctly). Any idea which is more accurate?

Thanks, Duke
 
Duke01 said:
Thanks Destroyer and Thefermanator...the existing prop has a bent blade and a another blade with a chip in it, so that might explain the reported max speed of 43 from the previous owner. I suspect that the speed was recorded from the dash speedometer. I am curious to see what the impact of a new prop will be and will follow-up in the summer after launch. I will note GPS speed measurements.

Regarding the weight, the brochures call out a weight of 1920 lbs, with an associated max hp of 200. Not sure how accurate that is (?). In 1989 and thereafter, the brochures noted a weight of 2300, with and an increase in max hp to 235 (if I remember correctly). Any idea which is more accurate?

Thanks, Duke
Click to expand...

Use the brochure that's the closest to your boat's year. Throughout the years Wellcraft was constantly modifying the hull, stringers, materials etc. so both of those brochures are probably correct. Added thickness of the transom for the extra HP, thicker stringers, larger gas tank, etc.... all of those things can and probably did change the weight.
 
I was thinking the 1920lb spec referred to dry hull (no gas in the tank and no motor)...earlier hulls allowed 235 HP, but later hulls like my '95 V21 only allowed 200 which always seemed odd to me. My best prop experience was a 17x15.25x3 SS by Power Tech...on a 150 Honda topped out at 42 and easily and economically cruised at 30. Generally a 4 blade prop has stern lifting characteristics which is good cuz V20s ride a bit bow high and like Ferm sez, may drop a couple of MPH off the top end. A good friend of mine has a 250 Verado on a 24 Everglades and loves his 4 blader...
 
reelapeelin said:
I was thinking the 1920lb spec referred to dry hull (no gas in the tank and no motor)...earlier hulls allowed 235 HP, but later hulls like my '95 V21 only allowed 200 which always seemed odd to me. My best prop experience was a 17x15.25x3 SS by Power Tech...on a 150 Honda topped out at 42 and easily and economically cruised at 30. Generally a 4 blade prop has stern lifting characteristics which is good cuz V20s ride a bit bow high and like Ferm sez, may drop a couple of MPH off the top end. A good friend of mine has a 250 Verado on a 24 Everglades and loves his 4 blader...
Click to expand...

Some hulls run faster with 4 blades, each boat is different. My 19 carolina skiff picked up almost 3 mph going from a 3 blade 17 pitch solas to a 4 blade 17 pitch solas. My hydrasports liked a large diameter 3 blade. Kept the same top end, but picked up big time in the cruise area. Many people would be shocked if they got with aprop shop and tried out some different props. Many think thete boats have quirks to them that may just be the prop. Others have fallen in love with there boats again after repropping. You just don't know unless you've taken it out and trief a half dozen different props. Sometimes all you need is a pitch change of just an inch to transform there boat, and other times they need a completely different prop. 4 strokes seem to do best with props that provide extra stern lift due to there heavier weights, so they like 4 blades.

As to the drop in HP for the V-21, it had to do with the euro transom change. Boats with a flat transom were rated at 235(except early hulls before the 235 existed), but the v-21 euro transom was only 200hp. And it also had to do with the change from flywheel hp ratings to propshaft. The old 235's were flywheel rated, and became a 185hp when they went to prop shaft rating.
 
THEFERMANATOR said:
As to the drop in HP for the V-21, it had to do with the euro transom change. Boats with a flat transom were rated at 235(except early hulls before the 235 existed), but the v-21 euro transom was only 200hp. And it also had to do with the change from flywheel hp ratings to propshaft. The old 235's were flywheel rated, and became a 185hp when they went to prop shaft rating.
Click to expand...

If one looked at the Euro transom design of the V21's from the inside it became evident why Wellcraft dropped the HP max. The bubble of the transom was not IMHO fully secured to the hull. There was a gap of almost an inch on both sides where the bubble came thru the main flat transom up to the first stringer. Why they didn't fill/glass in that gap and attach it to the stringer remains a mystery to me to this day, but when I removed the floor of my V21 to replace the rotted wood underneath and saw the gap it was one of the first things that I strengthened with filler and glass. I think that Bgreene also has strengthened his V21 the same way after learning of it.
 
Destroyer said:
If one looked at the Euro transom design of the V21's from the inside it became evident why Wellcraft dropped the HP max. The bubble of the transom was not IMHO fully secured to the hull. There was a gap of almost an inch on both sides where the bubble came thru the main flat transom up to the first stringer. Why they didn't fill/glass in that gap and attach it to the stringer remains a mystery to me to this day, but when I removed the floor of my V21 to replace the rotted wood underneath and saw the gap it was one of the first things that I strengthened with filler and glass. I think that Bgreene also has strengthened his V21 the same way after learning of it.
Click to expand...

I was the one that posted about that about 10 years ago after I looked at a v-21 that was a theft recovery, had the deck ripped out, and seen it. I was shocked when I could see light coming through the glass.
 
I also have a 78 with a 1988 150 Mercury and to me the best prop is 15 X 17 aluminum
I had a 13 X 19 s.s. And the would give me cavitation I'm very happy with my correct prop I think you will be too
 
Thanks again for the input. I need to make a correction to my existing prop number that I noted earlier. It is a 48-78120-19 (not 18). I think my first step is to purchase an aluminum replacement (matching existing) and then a test on the water with a gps to obtain an accurate speed reading. I will follow-up with you all, but it will not be until July since I have a list of projects to complete before launch.

Thanks, Duke
 
THEFERMANATOR said:
I was the one that posted about that about 10 years ago after I looked at a v-21 that was a theft recovery, had the deck ripped out, and seen it. I was shocked when I could see light coming through the glass.
Click to expand...

Wow. Thanks Ferm. Of course I was not a member or a visitor here 10 years ago so I never saw that post. I was just speaking of my own personal experience when I ripped the deck out of my V21.. But it's good to know that you saw and posted about it also. Always good to have corroborating evidence. I still cannot imagine what Wellcraft was thinking of when they built the bubble like that. It simply boggles the mind. :head:
 
I had got all excited when I found a v-21 theft recovery, drove 2 hours to look at it, and man was I let down when I could see under what was torn up. I thought maybe it was just that 1, but others confirmed it on theres too.
 
THEFERMANATOR said:
I had got all excited when I found a v-21 theft recovery, drove 2 hours to look at it, and man was I let down when I could see under what was torn up. I thought maybe it was just that 1, but others confirmed it on theirs too.
Click to expand...

Completely understandable. Man, that sucks to have driven 2 hours just to see that. I know I was shocked when I saw it. I was all like"WTF"? :head:
 
You must log in or register to reply here.
Back
Top