88 Wellcraft Antigua Prop Selection / Experience / Help

[seh...@gmail.com]

I'm looking for first hand experience if possible before buying
various props to find the best match for my 1988 Wellcraft Antigue
265.

I've used prop calculators and everything recommended for this boat
comes up as 14.5x15 to 23.

Currently I have a 14.5x17 on her. Top speed is about 30 in calm seas
and cruising speed is 26.

She seems to take a while to get on plane, but I'm used to a 20 foot
boat, this is a recent move to a 28 foot boat for me. Based on what
the previous owner told me, if there are 3 to 4 people on the boat he
would sometimes have to have them in the cabin to get on plane.

I'm wondering if I can use the trim tabs to assist in getting on
plane? I'm also wondering if I should increase the pitch?

My reasoning for that is with the 17 pitch top speed isn't to much
higher than cruising speed. So I wonder if it's possible the
additional weight reduces the speed from getting on plane.

The motor is a 5.7 with 260HP and it doesn't bog down at all when
throttling up. I'd also imagine with a higher pitch the engine could
be backed down to stay on plane and increase fuel efficiency.

Thoughts?

[jamesgangnc]

What is the engine rpm at full throttle, aka wot? That's how you select a
prop. A higher pitch may prevent the engine from reaching the correct rpm
range at full throttle. The service manual will have the correct wot rpm
but I'd guess it should be in the 4200-4600 rpm range. If rpm is low at wot
then you need a lower pitch. If rpm is high at wot then you need a higher
pitch.

Trim tabs always help with getting on plan and allow a lower crusing speed
on plane. The minimum speed that the boat planes at is more a function of
the hull that it is the engine and prop. Though some props will provide a
little more lift.

That is a heavy 28ft boat to have a single 350 engine. Some would probably
consider it under powered. How old is the engine?

<seh...@gmail.com> wrote in message
news:1185808545.1...@d30g2000prg.googlegroups.com...

[seh...@gmail.com]

Everything is 1988. Engine is in mint shape, I've had a compression
check and inspection done. (I know how to do it myself but when I
bought it I talked to the mechanic who checked it over)

The hull length is actually 26'5" but with pulpit it's 28'2".

Beam is 8'3" and weight is 5900lbs.

I'll play around with it soon and check the numbers. I know when I
went out with the previous owner during the sea-trial we'd kick the
RPM's down because they did seem to jump but I don't remember how high
they went.

WOT range is supposed to be 4400-4800 but I believe it was running
higher.

So let's go with a 26' cruiser. What is a "general" cruising and top
speed for a 26 foot hull length cabin cruiser with single engine? I
know hull design and beam make a big difference, but I'm looking for
some ball park numbers.

With the 14.5x17 according to his logs, gas mileage ranged from
1.5-1.9 depending on passengers and weather conditions. In 4-5' waves
it did not stay on plan and dropped to 1.1MPG.

I've been using online calculators but they all show a pitch of 10!!
I even plugged in other boat/engine configuration, it also recommended
a pitch of 10 for a Sea Ray Sundancer 260 so I'm not sold on it being
accurate.

[jamesgangnc]

Presuming your tach is working ok the next thing you need to know is wot
rpm. If you have a light load when you test then closer the the 4800 is
preferred. I believe the rule of thumb is 200rpm per inch of pitch. I
agree 10 is improbable. But 17 is not way out of line. There is no
"general" cruising and top speed for boats in that range, it will all depend
on the engine and prop. I suspect that boat was also available with a big
block. What is it about the performance you unhappy with? You mention the
time to get on plane as being slow. A higher pitch will not improve that,
in fact it will be even slower getting on plane with a higher pitch prop.
Boats are "single" speed so you are always striking a balance between hole
shot and top speed. If you think it is under pitched and has trouble
getting on plane the original owner may have deliberately used a lower pitch
prop to help with the hole shot. Tabs are a good addition. Power is a
personal thing but it's been my observation that engine size is the first
thing that suffers when the manufacturer is trying to keep the price down.
For me I'd have to have a 454 in a boat that size, or two 350s. You may
tweak the performance some with prop changes but don't expect miracles. The
local supplier may have a "try before you buy" policy on props which would
let you try a few out. Another good option is to buy used on ebay and then
sell the ones that don't work out. Used props hold their value. You'll
just be out a little shipping and long as you don't overbid on one.

<seh...@gmail.com> wrote in message
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[Steven Vaughan]

<seh...@gmail.com> wrote in message
news:1185808545.1...@d30g2000prg.googlegroups.com...

Is your current prop "cupped"?

[seh...@gmail.com]

Nope, not cupped as far as I know, it came with the boat. And yes, I
believe this boat had a big block option.

So I drove down to the marina yesterday evening and did some WOT
tests.

3800 RPM's @ 36 MPH. It was increasing slowly so I think I could have
hit 40MPH @ 4000 RPM's. The previous owner would hit 38MPH top speed
but the fuel flow meter would indicate 1.9MPG. I was pulling 2.15MPG
and that tells me she had more left in her.

I thought I had posted I think it's over pitched. Now that I have
these numbers and plugging them into prop calculators I'm seeing a
16x14 should be the best option.

I'm going to give that a try when I get a chance. I think the engine
is working to hard to get up to speed. This would cause carbon build-
up, pre-ignition, and may even score the pistons and cylinders.

Dropping to that pitch should increase RPM's to the 4400-4800 power
band and the increase in diameter should help with torque. The more I
think about it the more it sounds like the thing to do.

[jamesgangnc]

You can figure that each inch in pitch dropped will bring you about 200 rpm.
A 16 from a 17 may not be enough. Imho, if you tested alone you want to
shoot for the higher end of the range so that when you are loaded up with an
extra thousand lbs of friends and gear you're still in the ball park.
Dropping pitch will definately help with the hole shot. A cupped prop may
provide more lift but when comparing props consider that cupping is roughly
like an extra inch of pitch. So a cupped 16 is about the same as a
non-cupped 17.

<seh...@gmail.com> wrote in message
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[Steven Vaughan]

He's not going with 16 pitch...he's going with 16" diameter and 14 pitch.
Sounds right. I'd also have iot cupped.

"jamesgangnc" <ja...@nospam.com> wrote in message
news:jeHri.12729$rR....@newsread2.news.pas.earthlink.net...

[jamesgangnc]

I missed the drive in the posts? If it's a merc I'd guess it's a bravo. 16
won't fit on an alpha. That's a noticable increase in diameter but I agree
14 pitch is a better place to start.

"Steven Vaughan" <s...@doubletrouble.com> wrote in message
news:9JKri.1720$ox5....@nlpi068.nbdc.sbc.com...

[seh...@gmail.com]

That's odd. The Mercruiser web site is the one that recommended the
16x14 prop after I plugged in all the specs. Are you sure it won't
fit?

I'll do some more research. I'm going to see if I can find anybody
local that can do a try before you buy toward a prop.

[jamesgangnc]

I/m pretty certain that anything bigger in diameter than a 14.5 inch is too
big for the alpha leg. Look at the clearance between your current prop and
the plate above it. On all the ones I've looked at a 14.5 is pretty close.
I think a 15 might fit but I'm not thinking a 16 will.

I don't know that I'd put much faith in web prop calculators. Most people
change based on what prop they have and what is wrong with it. In your case
you are overpropped and probably need to go down about 4 inches in pitch.

<seh...@gmail.com> wrote in message
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[seh...@gmail.com]

Well I made it to the boat last night before it got dark and changed
props.

The closest I could find locally to what I wanted was a 15.25 x 15
prop. Since it was getting dark and I'm docked an hour away in an
area I'm not familiar with I just did 2 quick test runs. I broke 4000
RPM's and not sure how much higher they would have went since they
were just short channel runs.

She gets on plane in a matter of seconds now. I notice a huge
difference, but today will be the big test. It's going to be nice all
day so my girlfriend and I are going to head over to Put-in-Bay. I
didn't get a chance to see what my fuel efficiency was so now I'll get
a chance to do so.

[seh...@gmail.com]

So much for that...

Went to Put In Bay for the weekend. 17.5 miles from my dock. We had
a hard time getting on plane and were stuck at 16mph for the first 6
miles or so. Waves were >2. When we did hit plane we maxed WOT at
28MPH and 4100 RPM's.

Maybe I am better off running the 17 pitch prop. RPM's are low, but a
350 is under power. At least like this the MPG is around 2 and top
speed 40. I may still play around with it.

[jamesgangnc]

Obviously others have played around with props before you on this boat. It
might also be worth taking it to a truck scale and seeing if it has "gained"
weight since it was new. It's a 1988 so it may have absorbed a fair bit of
water.

<seh...@gmail.com> wrote in message
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