[Public-List] Propellers...

[Gordon Laco via Public-List]

Thanks,

Caroline laughed at me over the battery charger/charge state thing.  When I
noticed it had clicked off, I assumed a malfunction so went into 'grumpy
Gord' mode.... 'damned thing, what next, knew something would go wrong, hate
batteries, when I am going to find time to fix this, probably five things
wrong, not just one...' etc etc  until I realized that the issue was that
the 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 Surprise