New Props - Michigan DQX

[cww]

I am thinking about pulling the trigger on some new Michigan DQX’s, I have done some reading and everybody seems to love them on other boating forums, but none of them are Hatteras owners. It's mostly a lot of sport fish guys. I wanted to see if anybody here has tried them and what your experience was? It's supposed to be a more efficient blade design.

My current props are the OEM 28x31” dyna quads. I am thinking of using these as my primaries and using the originals as spares. The boat hits +/- 2300 with the 28x31’s with normal loading. I would be dropping 1” off the pitch to 28x30” to account for the higher blade area.

Thoughts?

[SKYCHENEY]

What are you trying to accomplish? More efficiency at hull speed? Faster cruise speed? Are your current props in bad shape?

I doubt you'll see much, if any difference at hull speed. And the cost is probably not worth it for the 1/2 knot you might pick up on the top end.

[Bob Bradley]

My "new" boat, an 86 Hatt 45C was repowered with a fairly open checkbook by a Dr back in 2001. The 6v92TAs were replaced with Cummins QSM11s making 535hp. They were matched with what the invoice refers to as "Michigan DQ style" 26 x 34 4 blade props. They were $3825 back then. I'd hate to think what a pair would run me today. The total refit, including a ton of other stuff such as new riggers, custom hardtop, Northern Lights genny, and full paint job to mention a few things, ran north of $200k. Based on that, I'm presuming a lot of thought, and possibly some trial and error iterations went into the prop selection process. That said, I couldn't be happier with the end result. I'm guessing that the original 6v92s were 550hp, but I don't really know, nor do I know the original performance numbers. The 535 QSM11's are certainly lighter engines. I cruise comfortably at 20-21 kts around 1850rpm, burning a combines 34 - 35 gph. She tops out at 29kts on the pins at 2300rpm up near 50 gph. I never run her for any length of time over 20gph per engine due to the dry exhaust and turbo design, which is prone to blowing exhaust and turbo gaskets if run hotter than that.

I don't know if these props are the same as the DQX you're considering, but if they are, they run great for my application. They have a very aggressive look to them as compared with the props on my previous '79 43C, which were much rounder and lobe like.

[cww]

What are you trying to accomplish? More efficiency at hull speed? Faster cruise speed? Are your current props in bad shape?

I doubt you'll see much, if any difference at hull speed. And the cost is probably not worth it for the 1/2 knot you might pick up on the top end.

The original DQ's work just fine, there's nothing wrong with them. The issue is I only have one set of props and live in an area of the St. Johns river that's really shallow. The entrance to and from the Ortega river where the boat lives has 1'-2' under the keel most days and half the places I go have 1' or so. The only thing you can really do about it is go idle speed, keep a good lookout, and hope for the best.

Whenever there is a windstorm or a king tide it picks up tree branches or whatever other crap gets blown into the river and sits under the surface waiting for you to hit it. The water's the color of used motor oil from all the tannins in the cypress trees, so you can't see anything. Not taking the boat out for a week or two after stormy weather helps, but then there are all the crab traps in the channel that you can't see at night and you'll catch one sooner or later. No matter what you do you will eventually ding a prop around here. It's unavoidable.

Most people here have 2 sets of props for this reason. With only one set my boat is out of commission for a month or 6 weeks every time that happens because you have to wait on the diver to take the wheel off, send it to the prop shop to get fixed, the shop to send it back, and then the diver to come back out and put it on. The spare set would eliminate all that downtime.

As long as I am spending the money anyway, I was thinking of trying out one of the newer designs and seeing what happens. It's basically sunk cost because I already needed a second set anyway. I was curious if anybody had tried them out. You probably ought to ask about it too, I would imagine if they're better you would gain some performance with those two big nuclear reactors you just put in your boat.

[SKYCHENEY]

I see your point but you don't want to buy something unknown and then have to pay to re-pitch them. If you stay with exactly what you have you might get away with just changing out one prop at a time. Send the damaged one in and replace without touching the other one.

For me, I'm not looking to gain a knot. She runs great with the 40 year old Federals that are on there right now. They were spares off of the 60C that I run with and they just happened to be the correct size.

[OVERBOARD]

That is what i did, exactly but i got them in Nibral. Took one pitch off and I can make full RPM's, huge difference on all aspects. I purchased them in 2020, installed in 2021. I needed spares so the old 1979 are used as spares if i hit something. 53 MY. picked up at least 1 Knot and every thing is much faster, no hesitation. Could not be happier.

[cww]

That is what i did, exactly but i got them in Nibral. Took one pitch off and I can make full RPM's, huge difference on all aspects. I purchased them in 2020, installed in 2021. I needed spares so the old 1979 are used as spares if i hit something. 53 MY. picked up at least 1 Knot and every thing is much faster, no hesitation. Could not be happier.

Thank you, I appreciate that. After reading this I went ahead and pulled the trigger on 28x30"s so 1" less pitch like they suggested and they should be here Friday. I will keep the other set as spares. I will let you guys know how it turns out.