1988 10 Meter-mid cabin, Need new propellers!

[Scott67]

Hello folks,
Looking for a set or a good resource for a set of 16 x 17 x 1.250 Max cup 3B propellers. If anyone knows of any, I would appreciate any info. Mine are getting to that point in life.

Many thanks!

Scott

[prowlersfish]

Check with Beacon Marine call Bob @ 609-713-4602.

[Scott67]

Update: after an hour of discussion with one of the Acme propeller engineers, going back and forth with numbers, we’ve decided on the following Acme propellers:

IMG_1749.jpeg (230.13 KiB) Viewed 9562 times

Looking forward to putting these on next month to see what improvements. More to follow with before and after numbers…

[prowlersfish]

Nice, I have heard a lot of good things about their propellers. I have a friend who runs them and swears by them. Did you change the diameter or pitch at all? Looking forward to hearing how they do. I'm also jealous.

[Scott67]

Yes, the engineer at Acme, based on my numbers (3900 rpm at 19 knots, tabs all the way down, boat length, beam, weight, etc...etc..) recommended going up to a 17 inch and down to a 14 pitch with a .030 cup.

They are really interested in getting my numbers up around 42-4300 rpm and about 25 knots. The engineer told me to keep the boxes because if the numbers aren't where they think they should be, he wants me to send them back and let them tune them until we are both satisfied. A real good experience with these folks so far. I couldn't be happier, even if the numbers cannot be achieved, I'll still be pleased with their customer service and willingness to make me satisfied.

Again, more to follow by the end of March...haulout is on the 15th.

[prowlersfish]

You definitely should be faster than what you are. The old props in poor condition are surely a factor. Look forward to the results. I expect a positive report.

[BobCT]

Interesting. When I went to four blades on mine, I also changed to 17x14 with a “light cup”, no # associated. If I still had the 454’s, I might be tweaking mine too depending on what you come back with. I’m still tabs all the way down, full time. I bring them up when I’m backing into a slip otherwise they never get touched.

[zedtwentyate]

I can't wait to hear how this goes. Make sure to report back. I want to change my stock mid cabin props so bad. I don't hate the performance of the boat, but I know there has to be more in her. Either better fuel efficiency or higher top speed.

I can run:

3000 - 18.5 MPH
3200 - 19.4 MPH
3600 - 21 MPH

The fastest she has ever gone with a light load and low fuel is about 28 MPH. But that's at 4200 RPM

[Scott67]

I'll definitely report back on the improvements/changes once done. My decision to stay with three blades vs four came after having it explained and now understanding more of the dynamics and characteristics of a couple of types of propellers...my old original" Dyna Jet" and my new "Acme" brand. The biggest take away for me was the differences in the DAR or Disk Area Ratio between the two propellers as pictured.

1.jpg (50.76 KiB) Viewed 8995 times

The DAR is the ratio of the total area of the blades to the area of a circle the same diameter. A DAR of 92 means that the total blade area is 92% of the area of the equivalent circle. These new Acme props have a DAR of 70.

Anyhow, this is all just talk and numbers. I hope to provide some real improvement data to reenforce them.

[prowlersfish]

I always preferred 3 blades for performance.

[zedtwentyate]

I'll definitely report back on the improvements/changes once done. My decision to stay with three blades vs four came after having it explained and now understanding more of the dynamics and characteristics of a couple of types of propellers...my old original" Dyna Jet" and my new "Acme" brand. The biggest take away for me was the differences in the DAR or Disk Area Ratio between the two propellers as pictured.

1.jpg

The DAR is the ratio of the total area of the blades to the area of a circle the same diameter. A DAR of 92 means that the total blade area is 92% of the area of the equivalent circle. These new Acme props have a DAR of 70.

Anyhow, this is all just talk and numbers. I hope to provide some real improvement data to reenforce them.

I keep checking back wondering how this thing is performing with the new props. Do you have a splash date?

[Scott67]

Well fellas, I have some "partial" results! I say partial results as I encountered a STBD engine overheating scenario while on my way back to homeport from the yards. However, these are the facts I have from the partial test;

4200/4250 RPM at 24.7 "knots" (as provided via Raymarine Chartplotter SOG), approx 1/3 tabs, and just above 3/4 fuel on both tanks. My travel lift operator states that the boat weighs in at 18000 lbs (not sure where the Mrs. has all that stuff)

Data was collected shortly before I was able to fully adjust trim and plane angle. Plane was achieved with zero tabs. Then, once I started adding some tab to get the bow down and get rid of the "mid-cabin STBD list", the RPM started to increase as well as speed. That's when my STBD engine started overheating (220 deg) due to a fouled righthand exhaust elbow as it turns out. I'm rather upset as the risers are only two years old and I religiously conduct a freshwater flush when I know I'm not going to be using the engines for a week or better. In any case, once I get my new riser(s) in, there will be another test conducted and I will gladly fill in any updates to those numbers.

However, I'm very happy with the choice of propellers.

[mpjosh2001]

Do you have any results for the new prips after the exhaust repair?

[Scott67]

mpjosh2001,
Sorry for the delay in replying, but the results still stand. I'm still getting every bit of the following: 4200/4250 RPM at 24.7 "knots" (as provided via Raymarine Chartplotter SOG), slack tide, approx 1/3 tabs, and just above 3/4 fuel on both tanks.

What I have also realized is my midrange cruise (2800-3000 RPM) has gone up to around 16 knots, whereas before the switch, I was making only around 12-13 knots on a good day. In and around the harbor maneuvering has been improved as well, much more bite when I shift into gear.