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

[Robert]

NautiMoments, solve the ventilation problem by either cupping the prop slightly, swap to a 4 blade prop, or lower your outboard by one bolt hole.

[Frank C]

Bob - you're referring to the trailer? Haft'agree. The hull afloat seems unphased by the extra motor weight. But there are two issues of larger motors that bothered me:
- the ever-increasing loads on that little 3500 axle;
- the effect of larger motor dangling & bouncing 3' aft of the last trailer bunk.

Roger clearly got the message and upsized the trailer for the 26M. In fact, not only did they go up to 15" tires, they've also upsized to a 4200# axle (more info later, it needs a different thread).

But Roger still has that generous overhang. Just one opinion ... I wait until I'm close to the ramp before filling my fuel tanks, just to help mitigate the excess aft-loads (regardless of gas prices - up 'till now).

[NautiMoments]

I know what you are saying Frank. I keep all my cockpit stuff, fuel tanks etc, in the truck until i am at the ramp.

[NautiMoments]

Robert, the only adjustment I see on the motor seams to control tilt limits. The dealer installed the motor as low as he could. I was thinking of getting a smaller diameter prop, thus should I go to a courser 3 bladed or a std 4 blade? I know Terry had some ventalation even with his 4 blade. I also was thinking of having it cupped.

[Bobby T.-26X #4767]

Just one opinion ... I wait until I'm close to the ramp before filling my fuel tanks, just to help mitigate the excess aft-loads (regardless of gas prices - up 'till now).

i agree.
we did the Lake Powell thing 2 years ago.
my X was nearly empty (gas, water, supplies) while we trailered the 500 miles.
and even then, i'm still constantly monitoring the tires and hubs for excess heat.

[Mark Karagianis]

Interesting - about the cavitation / ventilation mentioned. When we were testing I noticed this happening frequently on Aya's boat, especially with the 3 x 12 x 11-pitch prop. That never happens to me (in my 2005 M) unless I'm going over the top of a long swell in a run.

I think it's because he keeps so much stuff in the bow, his boat sits with the bow lower. Mine is light and more rear-biased.

Yeah, it seems that the 10-pitch is the most useful, and can someone describe their full / empty speed using a 4-blade prop with an M / DF-50?.

I don't want to be the slowest on our upcoming trip to Catalina.

Thanks, Mark

[aya16]

Mark like we were talking about on the boat. All the props we used the best was the pir. even though it was pitched wrong (9) instead of say an 11 it didnt blow out and the rpm range was near 7000. I think the speed we got from that prop would have been a lot higher had we been in the 11 inch pitch area. buttt we fine tuned and I believe that horse power is the answer. The etech 50-60 pushing a 13x13 prop at max rpm will run away from us. And not much we can do about that. But you have to take into consideration all the etech boats that went with you to Catalina last time were newer and slightly loaded. as they add weight like mine the torque of the suz will shine over the 2 stroke e-tech. when they have to drop to an 11 inch pitch they will be about the same as ours.

A believe these boats should have been rated right off the bat with a 90
that engine although small compared to whats on other boats will put the mac in the sweat spot every time. It still wont be a speed freak at 25 mph but as this boat planes the manners are improved 100 percent.

the boat can take it and I dont think it will effect sailing at all.

so for now im going with the pir 11 inch and will keep my 13 for a spare
next year I will go with an e-tech 90 white of course and I think Ill be ok with the power. As I sail most of the time anyway It isnt going to change much for me.

I think with your boat loaded as it is would be great (as good as can be )
with the 11 or 12 pir. Then next year we can walk into a evenrude dealer together and make a great deal on 2 90 etech's Then you will be waiting in Catalina for the other guys.

I have a 50 hp engine on my boston whaler 13 foot. That motor proped right only gets to 35 mph tops. When I bought the Mac I knew it wouldnt
get 22 with a 50. But twice the hp would.

The best thing for me when we tested the props was finding out that I was way down in the rpm range with my prop. That burns more gas and lugs the engine too much. I bet next time I go to catalina with the new prop
I burn only 3/4 of what I did before. And did you notice my boat planed
even with the ballast full with the 11, never did that before.

So conclusion for my boat: as heavy as it is the 11 inch pir. prop would be the right choice in props for me as the flex of the plastic prop will allow me to go up a pitch from the 10 mich. and it bit well enough to stop blow out.

your boat is lighter and 12 pir just might be the ticket.

[Bobby T.-26X #4767]

A believe these boats should have been rated right off the bat with a 90
that engine although small compared to whats on other boats will put the mac in the sweat spot every time. It still wont be a speed freak at 25 mph but as this boat planes the manners are improved 100 percent.

BINGO!
and Roger knows it...

Bob T.
"DaBob"
'02X w/ '04 90-TLDI

[Frank C]

That is certainly NOT true for the X. Even when I bought mine, the only alternative to the Suzuki 70 was a Honda 90 that weighed about 450 pounds.

The evolution of light weight 90s is about simultaneous with the 26M design, so it wasn't practical to go through much testing - factory had their hands full just squaring away all the other design issues - e.g. interior and rotating rig.

By now, of course, they benefit from the Microsoft effect.
Consumer Beta-testing ... after release!

[Terry]

I think the answer to ventilation is only half solved with a prop. I find with my 4 blade cupped Solas that it is minimal, but still if I am bow heavy and come up on the crest of a wave of course the prop is going to lift out of the water and ventilate, same goes for tight turns, the prop is going to come up a bit and ventilate. Half the problem with ventilation is about sea conditions, the other half is the prop. On the Honda there is only 6.25 inches radius from the prop center to the anti-cavitation plate, this barely allows for a 12" diameter prop (.25" clearance). Also with the 20" shaft even with the motor mounted all the way down the anti-cavitation plate only extends 1" below the center of the hull at the transom. At WOT I can look behind me and see the anti-cavitation plate skimming the water surface, with a 12" blade sitting .25" below that, ventilation is a foregone conclusion. Certainly a cupped 4 blade helps and with 11.4" diameter I have a .50" clearance to the anti-cavitation plate. I don't get the problems NautiMoments speaks of but I do get ventilation under certain conditions. I can't help but wonder if lower units that swing a 14" prop are the better way to go since there is a larger clearance factor to the anti-cavitation plate involved. A full inch of clearance would be helpfull.

[Frank C]

... still if I am bow heavy and come up on the crest of a wave of course the prop is going to lift ...

Terry,
Sorry to butcher (on edit - excerpt) your quote, but I was struck by your feeling that your prop lift might be due to a bow-down bias. Keep in mind that:

• - The 26X ballast tank was adjusted (late in model run, for heavier motors?);
  - The same is undoubtedly true for the 26M;
  - Motors w/ 14" props are 50 to 150 transom-pounds heavier than your Honda.

Maybe the Mac's natural balance has migrated for heavier motors? I'm sure that my Suzuki DF60
(335# dry) just floats the hull to her designed waterline. But all boats are sensitive to load placement ... so I concentrate loads at center & forward.

Stow your beer cooler & tools in "the WAYback" and keep 24 gallons of fuel aboard!

[Terry]

Keep in mind that:
- The 26X ballast tank was adjusted (late in model run, for heavier motors?);
- The same is undoubtedly true for the 26M;

Frank,
There are a at least a half dozen Macs in the Point Roberts Marina during sailing season and currently three of us M's on N dock (all Honda's). I have noticed when walking past any of them with full ballast that the bow sits a few inches deeper than the stern when veiwing the waterline stripe. I often empty mine on the way in to check the difference between full and empty. When empty the boat appears to have a more natural attitude relative to the waterline, it looks about level or natural. This leads me to believe that the M ballst was adjusted to be bow heavy, actually a look at the website diagrams confirms less ballast aft in the M, so perhaps the M was modified for heavier motors. NautiMoments is only about 15 slips down from me and I notice his bow sits very low at rest, lower than mine I suspect, maybe I should measure it. I have had occasion when cresting a wave to hear my prop go spinning wild out of the water especially when ballasted, but not every time. I still believe that ventilation is from the prop getting too close to the surface, especially in the case of the Honda.

On edit:
When one butchers a quote, words/phrases are removed from their original context, thereby changing the implied/intended meaning.

[DLT]

I have the same thing with my 240# motor. Unballasted, looks about level. Ballasted, the bow is significantly lower in the water... Of course, that's when viewed from the dock, so my fat a$$ in the cockpit might level it out a bit...

I like the idea forming... "But, Honey, if I loose wieght, we'll HAVE to upgrade the engine in order to level out the boat..."

[Frank C]

On edit:
When one butchers a quote, words/phrases are removed from their original context, thereby changing the implied/intended meaning.

Terry,
True enough, my 26X rarely ventilates its 14" prop - only in pretty rough waters or in very tight turns with moderate chop. And my model 2000 does have the more forward ballast bias of the later Xs. Sounds as if the Ms are even more pronounced.

But I guess that I was suggesting your problem is much more likely the difference in motor weights, rather than the differing clearances to ventilation plate (of 12" versus 14" props). In fact, unless one uses a 12" prop on a 14" hub, I doubt that there's any significant difference in said clearance, is there? IMO, the idea of using your load to compensate - at least testing the concept - is much quicker and more efficient than changing props ...
and/or dropping the outboard's mount ... and/or changing the outboard!


My point in quoting was specifically not to capture context, nor evaluate it .... rather, simply vectoring to a totally alternate concept ... and very sorry if it offended.
It's easily enough done without any quote.

[Mark Karagianis]

If Piranha made 10-pitch prop blades in the shape / size of their 9-pitch, it would be the perfect prop for my application. Just when I think that I might have it figured out - today the new Piranha 11-pitch blades arrived (one day after ordering!) and the blades are much smaller in area than the 9-pitch blades. They are more "conventionally-shaped". I won't be able to get on the water to test until next weekend. And that Michigan 10-pitch prop that I went to Catalina with I can't get now, as the Dealer sold it to someone else (I had exchanged it for a Michigan 3 x 12 x 11 pitch). Pitch, diameter, shape, size, bow-stern weight, this is hurting my head.

Can someone with a recent M with a DF-50 describe their setup that gets them 14 kts ballasted?

Mark