User Tag List
Thanks: 0
Results 1 to 11 of 11
Thread: Need Some Prop Advice
-
10-10-2021, 08:33 AM #15000 RPM
- Join Date
- Jan 2005
- Location
- Annapolis, MD
- Posts
- 390
- Thanks (Given)
- 0
- Thanks (Received)
- 4
- Likes (Given)
- 0
- Likes (Received)
- 15
- Mentioned
- 0 Post(s)
- Tagged
- 0 Thread(s)
Need Some Prop Advice
Need some prop advice. Boat is a 1979 23 Sea Ox Center console that I just rebuilt. New stringers, transom and deck. No foam. Has a T-Top but is rigged light and simple. No livewell, no trolling motor. Motor is on the transom since these hulls don't like brackets. Power is a 92 carbed 200 Merc that just got new rings and seals and has 25 hours on the clock. Runs strong.
With a 21 pitch Laser 2 prop, it has a great holeshot, good cruise (25 mph at 3,500) and tops out at 40 mph at 5,200. The Laser 2 doesn't seem to lift the bow much at speed which I think is part of the problem. Other folks with similar hulls (Jones, Sea Ox, Maycraft all used the same mold) are getting mid to upper 40s with the same power.
Using Merc's slip calculator, I get a slip rate of 28%. Clearly I need a different prop. Just looking to optimize cruise and top end without losing too much of the holeshot. Not looking to chase top end at all costs. Also, don't need to prop for heavier loads. Only ever fish solo or with my wife. Local folks with rigs like this with Mercs seem to like the Tempest Plus and Fury.
Would appreciate any suggestions you might have.
Thanks...Steve2ManyBoats.Last edited by Steve2ManyBoats; 10-10-2021 at 08:56 AM.
-
10-10-2021, 10:35 AM #25000 RPM
- Join Date
- Sep 2019
- Location
- Lake Keowee, SC
- Posts
- 243
- Thanks (Given)
- 8
- Thanks (Received)
- 25
- Likes (Given)
- 0
- Likes (Received)
- 62
- Mentioned
- 0 Post(s)
- Tagged
- 0 Thread(s)
28% slip seems almost too high? Is the speed in GPS? Are you sure the tach is accurate? Is that motor suppose to turn 5400 - 5800 at WOT?? If everything is accurate, it would appear that you need a prop with a lot more blade area to lift the boat and reduce the slip as you mentioned. I once owned a 23 ft Stingray cuddy with a 496 / Bravo that came with a 23P Laser II. That boat weighed about 3800# wet and I was surprised that the Laser II only had around 15% slip at WOT. However, a 23P Mirage had about 10% slip. A 24P Bravo 1 had about 7% slip. A labbed 25P Mirage had about 9% slip and was the fastest. The Tempest and Fury both have more blade area and have better bow lift on heavier boats than the Laser II. A Bravo FS has good bow lift as well. A Solas Scorpion has very good boat lift but they run very stiff so you might need a 19P Scorpion. Would be good if you can find some props to test first.
-
HydroSkreamin liked this post
-
10-10-2021, 11:46 AM #3
21 tempest or fury gets my vote too. Mayyyybe a bravo 22?
Hydrostream dreamin
-
10-10-2021, 12:16 PM #45000 RPM
- Join Date
- Jan 2005
- Location
- Annapolis, MD
- Posts
- 390
- Thanks (Given)
- 0
- Thanks (Received)
- 4
- Likes (Given)
- 0
- Likes (Received)
- 15
- Mentioned
- 0 Post(s)
- Tagged
- 0 Thread(s)
Confirmed the RPM with a second tach and the speed with a second GPS. Both numbers are accurate. The slip numbers seem way too high. My OEM Merc Manual for this motor lists the WOT RPM range as 5,000 to 5,500. I'm assuming this has not been superseded?
Thanks so much for the suggestions.
Steve2ManyBoats
-
10-10-2021, 12:25 PM #55000 RPM
- Join Date
- Sep 2019
- Location
- Lake Keowee, SC
- Posts
- 243
- Thanks (Given)
- 8
- Thanks (Received)
- 25
- Likes (Given)
- 0
- Likes (Received)
- 62
- Mentioned
- 0 Post(s)
- Tagged
- 0 Thread(s)
Good, the numbers appear accurate then. I was guessing at the rpm range, you appear to have the correct range and are in it. Have you, or can you raise the engine 1 or 2 holes? Sometimes that will increase slip as well, and when you go up in blade area and diameter you can often run the prop higher than you could with the Laser. Not worth trying until you get your new prop on.
-
10-10-2021, 06:15 PM #6
I had a 23 ft C hawk which is a very similar boat. It had a 150 Johnson on it with a 19 pitch SST prop it would run 40 miles an hour. I say this as a point of reference. Just curious but how low is the motor sitting? I also ran a 200 Mercury on a 21-ft Paramount with a 23 laser 2 prop. It would hit the limiter. Maybe raise the motor a little bit to get the RPMs up?
-
10-10-2021, 08:24 PM #7
Find you a 19 mirage plus and try it out. I run a 17 mirage plus on my 22.5 aquasport. 44mph 200efi 56-5800
Check out my onlyfans....
Subscriptions start at 1 gallon 100LL a month
-
10-10-2021, 08:59 PM #8
Take your prop and numbers (rpm's, speed and hull type) to a reputable prop guy and tell him what you want.
Unless you want to throw a bunch of money on someones favorite prop.
Lasers are a solid prop that can be modified for a great work prop depending on the application.
-
JBS liked this post
-
10-10-2021, 10:11 PM #9
An OMC Raker if you can find one.
-
10-11-2021, 07:49 AM #105000 RPM
- Join Date
- Jan 2005
- Location
- Annapolis, MD
- Posts
- 390
- Thanks (Given)
- 0
- Thanks (Received)
- 4
- Likes (Given)
- 0
- Likes (Received)
- 15
- Mentioned
- 0 Post(s)
- Tagged
- 0 Thread(s)
I actually happen to have access to both a 20 and a 22 Raker, but I was told by a number of folks that Rakers can be fast but have a pretty bad holeshot. If this is not the case, by all means I'll try them. Any idea where I can get the thrust bushing to use them on a Merc lower unit?
Thanks.
Steve2ManyBoats
-
05-05-2022, 12:31 PM #115000 RPM
- Join Date
- Jan 2005
- Location
- Annapolis, MD
- Posts
- 390
- Thanks (Given)
- 0
- Thanks (Received)
- 4
- Likes (Given)
- 0
- Likes (Received)
- 15
- Mentioned
- 0 Post(s)
- Tagged
- 0 Thread(s)
Tempest Plus is the ticket for my setup!!! Thanks for the advice folks
To update this thread, my 23 Sea Ox with a 200 Merc 2.5 was not getting the speed I expected. With a Laser II 21 it topped out at 40 mph @ 5,200 RPM. Was advised to get a Tempest Plus and drop down in pitch. Boy was that the right move.
With a Tempest Plus 19, I now get 44 MPH @ 5,300 RPM. But that's not the best part. My cruise @ 3,800 use to be 25 mph. Now it's 30 MPH. Prop bite is super and I can run whatever trim angle I want to. Couldn't be happier.
Funny thing, is that my 24 Carolina Skiff DLX with a Merc XR2 loves the same Laser II my Sea Ox hated. It does 45 MPH on that boat @ 5,400 RPM.
Thanks folks.
Steve2ManyBoats
-
tnelsmn, Forkin' Crazy liked this post
Similar Threads
-
Prop Advice
By Mturnquest in forum Props, Setup, and RiggingReplies: 4Last Post: 04-22-2015, 11:51 AM -
prop advice
By kwells77 in forum Props, Setup, and RiggingReplies: 4Last Post: 10-06-2010, 08:54 PM -
50 HP Mercury-10' boat -- Request boat tuning and prop advice + prop purchase
By Cedarwillly in forum Props, Setup, and RiggingReplies: 5Last Post: 09-03-2007, 01:05 PM -
Need Prop advice
By SRP71 in forum Props, Setup, and RiggingReplies: 2Last Post: 05-17-2005, 07:07 AM -
Need prop advice
By KG4 in forum General Boating DiscussionReplies: 3Last Post: 06-17-2001, 10:15 PM