[Public-List] Propellers...

[Gordon Laco via Public-List]

Good day friends,

Here's my report on the first season using the Campbell 'Sailor' propeller.

First, the 'Before' report.

Surprise is an apres hull #400 boat, with the usual two bladed prop, 13"
diameter, 7" pitch.  Our Atomic IV engine has the usual direct 1:1
transmission (so prop RPM = engine RPM)

What I liked about this set up was the following:

- superior 'grunt' when maneuvring... I liked the trememdous power the
engine delivered when making tight turns, stopping the boat with reverse
power (reversing in general)
- when idling at 600 rpm in gear, the boat moved at about 2knots which was
useful for maneauvring.
- maximum speed in flat water was about 6.7knots, which was excellent given
the hull characteristics of the Alberg 30
- headwinds made little difference in top speed
- towing our heavy Boston Whaler 'Squall' sailing dinghy knocked about 1knot
off speed, but we figured that was acceptable.
- fuel economy seemed to be about the 1 gallon per hour published as normal
for the Atomic IV

What I didn't like:

- the boat's economical cruising speed was 5.2 knots, which we achieved at
about 1000 RPM... Which is too slow for the alternator to produce a useful
return
- flat out full throttle was about 1400 rpm, better for the alternator but
gulping fuel, and cooling was not optimimum.

What I wanted to achieve...

- I wanted the engine to spin up closer to it's rated 'normal' operating RPM
to improve the output of the alternator and cooling systems
- I was intrigued by the promise of 'more horsepower in the water' given
that at 1000 rpm the Atomic IV is only delivering a small fraction of it's
rated 30 hp. 
- I was also intrigued by the promise of a lower engine sound level (it was
already nice, particularly when compared to a diesel) better 'grunt' when
pushing against a head sea or wind, and towing, as promised with three
blades vs two.

What we observed this past summer.  The Campbell Sailor supplied was the 11"
diameter 5" pitch they recommend for direct drive Atomic IV's for the Alberg
30.

First the good.

- the engine was so quiet even at full throttle, I disbelieved the knot
meter and double checked it with the GPS and a timed run.  The engine is
significantly quieter and smoother with the Campbell Sailor prop
- RPM rose as promised.  Flat out is about 1800rpm, we get 5.5 knots at
1400.  
- the engine ran cooler, more in the temp range recommended for the Atomic
IV engine.

And the not so good...

- there was a definite decrease in what I call 'grunt' when maneavring in
close quarters.  The Alberg 30 is particularly good with regard to using the
engine to spin her in her length but where response was immediate with the
old prop, with this one I had to wait for the engine rpm to 'spool up'
before feeling the kick...and the kick was less.  Not good.
- power in reverse was about the same.
- top speed even at the higher RPM was about half or 3/4 of a knot lower
than with the old prop.  Not good.
- head wind and seas, and towing the dink had a dramatic effect on speed,
much worse than before. Not good.
- fuel ecomomy, even when not towing and in flat windless conditions, was
much worse.  I had hoped that despite the higher rpm, since the engine was
not labour as it seemed to be before, that fuel consumption might be the
same or better, but it was not.

And now some good news...

I made a detailed report to Kelsey at Campbell Props... He is well informed
with regard to the various factors affecting propeller performance.  We
discussed pitch adjustment, but settled on increasing the prop diameter and
leaving the pitch the same as a cure.   We agreed that it seemed my issue
was excess slip, and increasing the prop diameter by 1" (thereby increasing
blade area) would lower slip and hopefully offer me the cure I'm looking
for.

He was prompt and cheerful about offering me a new prop, even offering me
the new prop before sending the old one back to him.  Because I couldn't
comfortably change the prop till the boat was hauled for the winter, I
thanked him and suggested that if he sent me the new one after I'd sent him
back the old one that would be quite fine.

Surprise came out of the water last week, so I've pulled the prop and will
be sending the D11xP5 three blade Sailor back to him today.  I can't wait to
try out the D12xP5.

If that doesn't work, I could always do what Bob Crinion in Nova Scotia
did... Remove 1" from the diameter of the stock 2 blade D13xP7 thereby
achieving the RPM increase he sought.  I didn't discuss noise with him when
I visited his boat last spring, but since the tip clearance is a little
better I expect his 12" diameter prop is a little quieter, although it'll
still have the thump that is inevitable with two blade props (this is caused
by lack of water flow when the blades are lined up with the stern post.
Three or more bladed props don't develop this because two or more blades are
always in clean water flow and pushing...)

Cheers - 

Gord Surprise #426

I can't wait to try the new one out.



On 2016-11-16, 4:05 PM, "mpcbi at aol.com" <mpcbi at aol.com> wrote:

> Hello Gordon,
> 
> I am very curious to know how you found your first full season with your new
> propeller?  I have a two bladed original which is somewhat unresponsive and
> was intrigued at the start of the year by your experience.  (noise, vibration
> reduction, power in reverse, strain on the old A4) I would certainly enjoy
> hearing if you are still happy if you are inclined to share your thoughts!
> 
> cheers,
> 
> Maurice
> Avoca 322
> 
>   
> 
> 
> ---- Original Message ----
> From: Gordon Laco via Public-List <public-list at lists.alberg30.org>
> To: George Dinwiddie <gdinwiddie at alberg30.org>; Alberg 30 Public List -- open
> to all <public-list at lists.alberg30.org>
> Sent: Sun, Jun 5, 2016 11:44 am
> Subject: Re: [Public-List] Propellers...
> 
> Thanks,Caroline laughed at me over the battery charger/charge state thing.
> When Inoticed it had clicked off, I assumed a malfunction so went into
> 'grumpyGord' mode.... 'damned thing, what next, knew something would go wrong,
> hatebatteries, when I am going to find time to fix this, probably five
> thingswrong, not just one...' etc etc  until I realized that the issue was
> thatthe batteries were indeed fully charged...On 2016-06-05, 11:11 AM, "George
> Dinwiddie via Public-List"<public-list at lists.alberg30.org> wrote:> Sounds like
> a complete win, Gord.> > On 6/5/16 10:42 AM, Gordon Laco via Public-List
> wrote:>> Hello friends,>> >> I¹m sorry to reintroduce this topic... But I¹ve
> changed propellers and>> thought I¹d share the experience.>> >> Some of you
> may recall that I have pontificated about taking a Œdon¹t>> change¹ position
> with regard to the prop supplied by Whitby Boatworks with>> the Atomic IV
> engines many of our boats have.>> >> Well this spring I was thinking about the
> engine and decided to try a>> change.  Last fall¹s ŒMisery Trip¹ reached a
> crescendo of suffering with a>> slog to windward in 40 knot winds and a sharp
> chop...  We were nearly>> stopped a few times, mostly by wave action, but
> SURPRISE trudged along and I>> would say coped better than our companion¹s
> boats which were all fin keeled>> yachts fitted with diesels.    So power
> delivered to the water wasn¹t the>> issue... What I was thinking about was
> alternator performance and cooling.>> >> Cooling has never been an issue with
> our engine, particularly since I>> replaced the old water pump with the
> upgrade offered by Moyer.  However I¹ve>> been keenly aware that our cruising
> RPM of about 1000 doesn¹t really spin>> things down in the engine compartment
> fast enough to deliver what the>> alternator is theoretically capable of.>> >>
> I liked the look of the narrowed bladed ŒCampbell¹ props I¹d seen on other>>
> boats, and liked the idea of increasing revs while at least keeping the same>>
> Œpower in the water¹ situation the stock two bladed prop gave us.  So I>>
> ordered the Campbell which they recommend for Alberg 30¹s fitted with Atomic>>
> IV engines with 1:1 transmissions.    The vendor said he was certain what>>
> shaft diameter and taper my boat has... But because I¹m a doubter, I sent>>
> him my old prop for reference.>> >> In due course the new prop came back along
> with the old one (and he was>> right, he did already know the specs).  I
> couldn¹t wait to try it out.>> >> We installed the new prop as part of my
> condensed spring outfitting (and no,>> I did not do the cap rail job I wrote
> about earlier.  I got busy with work>> which took me away most of April and
> May so that¹s that on that job for>> now).  Eagle eyed Rod saw the shiny new
> thing and commented ŒI thought you>> said...¹     Well I know what I said, but
> what the heck...>> >> We got SURPRISE into the water and after securing the
> rig, started up and>> started the two hour trip back to our sailing club.
> First thing I noticed>> was that I seemed to have a lot more power in reverse
> than before.  The>> second thing was that prop walk seemed to have
> dissappeared... Amazing.>> >> The only negative comment I¹d read about these
> props on line referred to a>> supposed loss of maneuvring power... But I was
> able to do the usual spin>> within her length that SURPRISE normally does.
> Motoring out of>> Dutchman¹s Cove Marina, I found that our speed at idle was
> lower, and that¹s>> a good thing of course not unexpected because of the finer
> pitch.  Once out>> past the breakwater, we opened the throttle and both
> Caroline and I were>> amazed.  Boat speed climbed to 6.6 knots as usual for
> full throttle, but>> there was no roar and vibration from the engine.  I won¹t
> say it was as>> quiet as electric, but the change from how things were was
> startling and>> dramatic.   We were so quiet at full speed I mistrusted the
> knotmeter and>> fired up the GPS, but it confirmed the speed.  Amazing.>> >>
> We found our old cruising speed of 5.2 at 1000rpm was now 5.2 at 1400 (this>>
> second RPM was full out open throttle with the old prop). Yes the engine was>>
> spinning faster, but at the same throttle setting and clearly not labouring>>
> quite so hard.   The boat was so quiet we didn¹t feel like we were moving,>>
> so we did the trip at 6+.>> >> So the prop change is rated a total success.
> But there was a surprise in>> store for us.  Because I was away so much I
> didn¹t do my usual thorough>> recharge of the batteries... We started up after
> launch on what was left in>> the batteries after the Misery Trip and months of
> winter lay up.   I was>> glad there seemed to be enough juice to spin the
> engine.>> Yesterday I decided to connect up the battery charger and run it all
> day...>> But after only moments, the charger was indicating full charge.  I
> assumed a>> problem with the charger but after investigating, realized that
> the>> Œproblem¹ was that the battery bank was indeed fully charged and the>>
> automatic function on the charger was sensing this and shutting off.>> >> How
> could that be, I thought... Then it occurred to me that the alternator>> must
> have run up the batteries on the trip over from the marina.  In the old>>
> days, the alternator barely kept up with the engine¹s requirements and I¹d>>
> had to charge from shore power periodically.  So it appears that whatever>>
> was in the batteries at launch, the engine itself topped them up in the 90>>
> minute shot over under power (wasn¹t two hours because we galloped home>>
> faster).>> >> Happy happy.>> >> Gord #426
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