Michigan/Piranha/Solas Props on Suzuki DF50, 26M

[Captain Steve]

Mark, do a search for cupping...I recall last go around a highly regarded place was here in Oxnard on 5th strret, or at Ventura Harbor. Will try to search and report back if......successful

[Captain Steve]

Found them...I went there with a friend..got this trick computer device for measuring your props. It can make changes and calculate improvements.

Valley Propeller Service
(805) 644-5055
2805 Palma Dr
Ventura, CA 93003


Valley Propeller Service Home Page
Home Page. 805-644-5055, 2805 Palma Dr Ventura, CA 93003 (805) 644-5055 FAX (805)
644-0243 E-Mail: [email protected] We Ship Worldwide. ...

www.valleypropellerservice.com/ - Cached

[Mark Karagianis]

Thanks Steve. But I need to find a prop shop close enough so that I won't have to take a half-day off work, or one that is open Saturdays. Funny, the "Valley" prop shop is in Ventura, not the San Fernando Valley!

Anyone know of one in the West Side or South Bay areas?

Mark

[Robert]

Take care to search for a prop shop that knows what its doing and mail it to them. When I had my 3x12.25x9 stainless prop cupped, I sent it all the way back down under to Steve Evans at Solas in the same box that they used to send it to me. I would find a prop place in the USA to reduce the time delay and cost of shipping.
..
Try this link to find someone near you:
http://www.props.com.au/

[Mark Karagianis]

Thanks for the tip, Robert. I have been really busy at work and so have not been able to investigate my next move regarding the Solas prop.

Hey, I looked into your comment regarding cavitation plate height. Mine is 1" above the projected line along the bottom center of the hull. I think that my motor is mounted as low as it can go. And your is an X, correct? Is this normal for most motors on an M? Is anyone else able to verify this?

Mark

[Robert]

I think you have discovered your problem. The motor is mounted high enough that the tops of the prop blades can grab air.
..
My Mac is an X. I was not aware that the M required a longer shaft outboard. Could your outboard be lowered if noew holes were drilled? On my X what I meant by as far down as possible is the motor was as far down as it would sit if no bolts were installed yet.

[Mark Karagianis]

I am at work so I am unable to post a photo now, but the assembly that the motor hangs from is mounted similar as yours is, in that it is as low as it can go. Like it was hung there and then the holes were drilled.

It does not look like there is any possibility of lowering the internal pivot that mounts within this assembly; this enables the motor to turn left and right.

But I have not had any trouble with ventilation on anyof the other props.

Update 6-13 Cap'n Steve - I have checked out a couple of prop shops by phone and lucked out - Brian at Valley Prop will open the shop early (8am) on Saturday the 24th for my appointment. Want to meet Diane & I & have breakfast afterwards? Unfortunately I won't be able to bring my boat & do a sail with you, maybe another time. Any chance I could get one of those USGC Safety Manuals from you that might be left over?

The other place that checked out good was Wilmington Propeller (Gary) 310 / 518-1133 in Wilmington.

Update 6-20 Looked at the cavitation plate height again, both with the boat in the water and and on the trailer - it's 1" below the bottom of the boat. Maybe I didn't do it right when I put a ruler alongside the bottom of the hull before. At least I don't have a problem with that. Only a few more days until my appointment in Ventura . . .

Mark

[Mark Karagianis]

Ok, I visited Valley Propellers, met with the owner Brian, and he is cupping both my $ Solas prop and my cherished 3x10x12.25 Michigan prop. Turned out that the Solas was slightly cupped (there ARE degrees of cupping) and he was sure that he could add more and bring down the rpm while enabling it to hook up better. His shop is amazing and they even make their own design props for lake excursion-style boats.
IMPORTANT TIP - I learned that it is important to re-torque after one or two uses when you re-prop, as the rubber hub will deform slightly under use and the re-torquing squishes it more and keeps it firm - that's good.

I had brought my Michigan prop along for laughs and when he saw it he said that he could cup that one too under the minimum labor charge of $75 bucks I was already paying. We looked up the Max HP of the Suzuki and it is 50 hp @ 5,900-6,600 rpm. So he thought that I might as well cup that one too, as my peak rpm from the Michigan was 6,300 to 6,400. If slightly more cup is added, he felt that I could expect 6,000 rpm empty with a higher top speed AND a higher speed with full ballast. Best of both worlds. He said that I should have just come to him first.

He doesn't like the Piranha props, and Mike (AYA16) you're right, they do flex under load . . .

Also, he thought that my high-speed pulsing (6,700-6,800 rpm) with the Solas may have been the result of the motor banging off the rev limiter. I guess that I would have to hear that on another motor because it just didn't seem like that to me, and I tested that (I think) by deliberately raising the motor at WOT with another prop to see how high the rpm would go, and it just stabilized at 7,000 rpm.

This is starting to feel like a blog! Mark

JULY 12 - I am expecting to receive my props back tomorrow via UPS. Now I'll have to test them both the same day; this weekend we're motoring to Anacapa Island & sailing back. Which prop to test first? I'll have 6 adults aboard. Decisions . . . .

July 13 - Got the props back, and I can see obvious balancing efforts on the Michigan; it has light sanding marks on all of the blades, and it now has cupping it originally didn't. Both props have been balanced and painted black, but the paint was tacky when they put them in the box with the shredded newspaper. So can you believe it I've got little dimples and mars in the paint on both! I can't stand it as I'm a perfectionist - I'll have to try to touch up the spots tonight. If I leave them in the sun tomorrow they'll bake-in in the 105-degree heat. I've decided to use the Michigan 1st as we're going to be loaded and the Solas was so bad initially. Maybe if I get the boat rigged real fast I can do a quick unloaded test, as the Ventura Harbor ramp is so close to the sea wall.

[blanton]

Our M only has a few hours on her this first season. Been to PWS (Prince William Sound) a couple of times. I've started out with a (Suzuki) 17p 14d and that's clearly not the ticket as I only turn up to 4800. My next prop will be the 15p 13.5d as recommended by my S. dealer and coincidentally someplace above in this topic as well. We've only sailed fairly well loaded as Alaskan's are wont to do, and pulling an RIB too.

I didn't make much note of my speeds as I was focussing mostly on RPM thus far. Besides, with our tides I'd need to make test runs both ways. On flat water the boat is VERY stable on top of the water with ballast empty (OR full). Turns are smooth and silky. I've mostly messed around between 3 & 4,000 RPM. Certainly no signs of cavitation at any speed. Just smooth stable performance.

With the funny hump-back spoiler/intake on the 140 she wouldn't quite tilt up under my helm seat so I ordered the two plastic bits that differentiate the 90 & 115 motor cover(s) from their sibling. The 140 now has the flat-top profile of a 90 and fits better under the seat at tilt. The "hump" would not fit under the trailing edge of the seat at all. Now it tucks in with inches to spare.

I peeled off the "140" numbers as well and now I don't have gawkers at the ramp. Looks like a 90 (same size and shape), but lighter by several pounds.

After the season I'll get one of our local glass fab shops to raise the butt platform of the helm seat a couple of inches for more tilt.

We usually travel with 40 gallons fuel in the cockpit (12 + 12 + 16) and 14 gallons of water forward.

Looking forward to getting things dialed-in prop-wise. I feel the 140 is a viable motor choice for the M. Best power to weight (claimed) in the 4-stroke field. Center of mass migrated forward with off-set crank and drive-shafts. Should have similar SFC (specific fuel consumption) numbers at a given H.P. to rest of the Suzuki 4-stroke clan.

Even with the wrong prop the boat does not feel underpowered ;^)

http://web.mac.com/blanton/iWeb/Site/Library.html

[Night Sailor]

I'm with Robert. I'd be surprised if any prop you choose will perform well and consistently on all angles if the cavitation plate is an inch above the bottom of the boat. Bubbles from the keel slot will tend to pop up under that plate at speed, mixing with the water the prop must grab.

Do keep us informed about your prop experiments, as we might all learn something unexpected. If however, you find you still have a problem, and can't lower the motor on it's mount, then get an extension for the lower unit. All makers should have them in varioius incremnets like 1, 3, or 5 inches.

[Mark Karagianis]

Blanton I'm impressed by your 140, but I think that you have a serious case of the Alaska Syndrome ("Everything is bigger in Texas, but Alaska is bigger than Texas.") And 40 gallons of gas? Are you sure that you need a sailboat? I believe in keeping weight down in order to have decent sailing performance - I bought this boat to sail, and the quicker-than-normal-sailboat speed gives me the range to do day-sails that I wouldn't normally be able to do, like visit the Channel Islands for the day - and return before dark!

Night Sailor, my cavitation plate is 1" below the bottom of the center-hull line, I had hurriedly measured it and as I said in an earlier post I was wrong.

So Saturday 7/15 I ran my Michigan 3x12.25x10 pitch with 6 persons and all of their gear (3 coolers, 5 duffel bags, huge purses, gobs of warm clothing, inflatable, two crates of food & drink) aboard. We powered for 1.5 hours WOT, full ballast for a few minutes at 11 kts @ 6,000 rpm, then with empty ballast into light winds for the remainder, I averaged 13 kts @ 6,200 rpm. We went to Anacapa Island, anchored, sailed around the island, and then sailed most of the way back. A typical So. Cal Mac day!

But with so much weight, I was unable to make a firm conclusion as to the effectiveness of the cupping. My earlier tests several months ago when lightly loaded had 12.6 kts @ 6,300 full ballast, and empty 15.5 kts @ 6,300. My feeling is that I dropped 200 rpm but gained more power / speed. Also, my fuel consumption for the day (total 2.5 hrs WOT) seemed to be lower at 9 gal. I'm convinced that this prop can do both fully loaded and empty very well. The Pirahna could only do empty light load. I will test the Solas the next time out, under light load, I promise.

Mark

[Mark Karagianis]

Well, the website's back up and I can report that I finally got to try out the 4-blade Solas 4x11.8x9 after the cupping - the short take is that it works great but is not perfect. We did a nice triangle course; power into the morning light wind from Marina Del Rey west to Malibu, then add ballast, raise motor & sail out into the Channel on a beam reach, and then back to MDR wing & wing (no ballast and raised cb, a little scary at times!), a great motor-sailing day.

For the 1.5 hrs motoring at WOT, with empty ballast, two crew and light load, we did a consistant 14.8 - 15 knots (17 mph) @ 6,100 rpm. When I did a loop back to try it running with the wind, we were doing 15.5 - 16.2 kts @ 6,200 depending on the swells, which were very small.

The prop makes the engine sound quite different; even my Dad noticed, he said that it sounded "deeply powerful" and I think that fits well. Docking was great, hook-up and getting to speed is very fast (you gotta hold on), and at speed there is a deep sonorous warble. This is better performance than the cupped 3x12.25x10 Michigan that I have been using. The real eye-opener is the ballasted performance improvement, with 13.5 knots @ 5,900 rpm running wind abeam. I could not even use the prop with full ballast before, as it would ventilate so strongly. I think that if I had had all of the people & gear aboard like last time when I tested the Michigan the results would've been about the same. I think that under the same exact conditions, the Solas is better-performing and delivers better fuel economy. I could throttle back signiificantly and not drop much as much speed as with the Michigan.

Now for the bad part - at WOT flat seas and light wind, once in a while the prop would begin ventilating, rpm would fluctuate at 6,600 - 6,900 (rev limiter?), and would not recover until I would throttle back, slow to 12 kts, and hook up again. This would happen weather or not I had full or empty ballast. I tried moving my human ballast (Dad) to the forward bunk and back but that didn't matter either. This might occur twice in five mintes and than not again for 30 minutes. Really wierd.

So I've got a call into the prop shop to see what they recommend - maybe they can get another 75 bucks from me. I think that maybe it should be slightly re-pitched (lower, maybe 8.5) and cupped more, to get back to 6,400 rpm with no ballast, and then it would do 16 knots empty. Then with full ballast it would probably do 14.5 knots @ 6,100.

We seem to always empty the ballast now when we power. So for an light boat, empty ballast, powering - like if Diane & I go to Catalina next month for the lobster hunt, the prop to use would be the Pirahna 1211C, which empty did 16-16.5 kts, but was terrible with full ballast.

But for now, the Solas stays on the boat, and now the Michigan is going to be the spare.

Mark

[Frank C]

... We seem to always empty the ballast now when we power. ...

In the past 6 pages of prop testing, that's the biggest change you've made!
But Mike was right, your testing efforts (and Robert's before you) plus your record of results adds special value for all DF50 owners, and maybe other 50s too.

It takes time to understand the Mac and time to become familiar with its handling. But then add just a modicum of "attentive skippering" and the Macs are fine performing "motorboats" with a reasonable crew size. Glad to see you've reached the comfort level to really enjoy the Mac!

Your Anacapa cruise with six aboard was beyond my limit of safe, MT-ballast motoring, surely requiring all hands to remain in cockpit or lower, methinks. The only issue with larger crew size is the degree of crew wt. versus hull weight. Six adults can exceed half the weight of an empty boat, and they're mobile. This means they can detract from stability just like a partially full ballast tank, and means they must remain attentive to a Skipper's safety instructions.

[Terry]

Hmmm...Curious,
I have the Solas Alcup 4 X 11.4 X 9.75 and I have no ventilating experience - is it due to the slightly smaller diameter? The radius to the anticavitation plate on my Honda is 6.25 inches so I have about slightly more than 1/2 inch of clearance, perhaps this helps prevent ventilation. The Alcup is a medium cupped propeller and I get very similar speeds/performance with mine as Mark does, I am quite happy with it, only wish I could have it in SS but that is too costly. The four blades seem to be what is needed to increase the blade surface area and get these big boats moving with the small engine. I also notice a difference in engine sound between my 3 & 4 blades but 4 blades gives improved maneuvering around the marina.

[They Theirs]

Mark Karagianis
We have been very interested in your propeller reports. This detailed testing certainly provides direction for all DF50 owners. I like the small streamlined lower unit of the DF50 combined with its compact three cylinder balanced design, and admittedly have not taken the propeller plunge even with Roberts and others successful reports. We never expected the Michigan Wheel to provide such good results after a prior report regarding venting exhaust from a poorly fit thrust spacer with limited factory help. Were interested in the 4 ear Solas from early posts, and I must say you’ve become a benchmark for reporting in great detail with unbiased posts. May I ask if you might employ a very modest amount of your M daggerboard during testing? It may well be of little benefit but I believe Robert tests were on the X with a large centerboard slot. I’m interested on your thoughts for future testing if you have not already covered this or for lack of any reason.



Thanks Mark for such informative reports.