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Author Topic:   40hp 4 stroke Mercury hole shot resolved!
awares posted 03-21-2001 10:25 PM ET (US)   Profile for awares   Send Email to awares  
I am one happy 2001 13' Sport owner this evening. As some of you know I have bought a new sport with the 40hp 4 stroke engine and was very unhappy with the hole shot performance.

Everything else about the motor I love. Easy to start, no smell, 10.5 miles per gallon, no oil to be added, and no problem with the weight. No water over the back of the transom and sits fine in a static position.

Testing the boat with the standard stock prop that came with the boat I achieved the following results. (15" aluminum pitch prop)
5800 rpm's, 37-38 mph, for ever getting on plane.

Tested this evening on Lake Travis with a four blade stainless built by Power Tech out of Shreveport, LA.
Prop Model: M70 SCB4R 12 Satin
(4 blade-12 pitch)

Results: Great hole shot! "Immediately on top of water. Maximum rpm's of 5900 and unbelieveable top end speed of 45-46mph. This motor performed so differently I first thought I had a standard 2 cycle motor.

I can now move on to rigging the interior because from a motor performance I am stopping. Pulling a skier will not be an issue from this point forward.

I credit this to Mike and J.T. Nettle at Nettle's Prop Shop in Austin, Texas for having the knowledge to hit it right on the very first try. It is hard to find dealers and people that know what to do anymore.

Also Power Tech's web site is Also feel free to call the Nettle's in Austin Texas if you have a question. Phone number is (512) 837-7707.

I am only a consumer that demands top reliable performance, I am not a salesman.

whalernut posted 03-22-2001 07:59 PM ET (US)     Profile for whalernut  Send Email to whalernut     
Those Dudes did Magic to you`re motor! I can`t believe the difference in performance you are telling us! That 4 blade prop is like a miracle! Congratulations, and keep us posted on later performance results with full weight, skiiers,etc. Regards-Jack Graner.
Bill Davis posted 03-22-2001 09:12 PM ET (US)     Profile for Bill Davis  Send Email to Bill Davis     
Awares: Keep us posted on all further developments, and by that I mean on your progress and thoughts on interior. Maybe ought to use your "outfitting has begun" subject line.
I'll stir that a bit right now.

thanks for the education--I wonder if I would greatly benefit from such a prop. I have a 30merc 2 stroke on my 2000 sport 13' and the prop is pretty nicked up....


Tom W Clark posted 03-22-2001 09:48 PM ET (US)     Profile for Tom W Clark  Send Email to Tom W Clark     

Are we to understand you correctly: you now have a 13' boat that is capable of going 45 mph? And the boat is within its maximum hp rating? When I had a 13' I remember it went about 35 mph, and being that close to the water it seemed pretty damn fast! Did you order the nitrous oxide option on your motor?!

awares posted 03-22-2001 10:39 PM ET (US)     Profile for awares  Send Email to awares     
The top end speed was beyond my wildest imagination. I own a 1968 13' Whaler that I keep trying to compare this boat against. I have realized that I can not do that any longer because they are similiar in some areas, but overall performance is so much different.

As I stated in an earlier post I thought I would install a new 40hp 2 cycle engine on my old Whaler. If I can scrape up the difference between the two when the hull and interior is completed I will now buy the 4 stroke. I just need to think through the weight addition between the two and the addition of the set back plate that will accomandate a long shaft motor.

If someone had told me I would be able to go faster than 40mph in this boat I would have taken that bet. Well it is true and I still can not believe that I achieved 45mph.

Whaler needs to go back and do their own validation tests on several prop types. I personally feel that they could sell more of these boats if they would maximize the performance and share it with the general public.

I know that bad news travels faster and further than good news. I feel sorry for the guys that are not as persistent as we are with our Whalers.

2001 13 Sport Owner posted 03-23-2001 12:08 PM ET (US)     Profile for 2001 13 Sport Owner  Send Email to 2001 13 Sport Owner     
Awares! Sounds like the guys at Nettles really solved your hole shot performance problem. It is unbelieveable how the right prop can improve performance. As you know, my boat has the 25HP 4-Stroke. I am trying to get my dealer to trade out my engine for the 40HP 4-Stroke. His most recent recommendation was to trade my boat in on a 40HP 2-Stroke. The dollar difference would be minimal. However, the reason I went with 25HP 4-Stroke in first place was because I like the 4-Stroke engines due to the lack of smoke and quietness. I also believe the 4-Strokes are probably better when it comes to maintenance.

I had also considered buying a used 15 Dauntless, but have decieded against that as long as I can improve my hole shot perfromance and top end speed. I really like the way my 13 Sport handles and it is a perfect first boat for learning the bays along the Texas Gulf Coast. When I am ready to upgrade to a bigger boat, I will go with something around 17 to 20 feet long.

I will let you know what I decide to do. Thanks for sharing your results with us.

whalernut posted 03-23-2001 05:04 PM ET (US)     Profile for whalernut  Send Email to whalernut     
Maybee the trick to the 4-stroke magic is to swing a 4 blade prop! It sure worked for Awares. Because of the (4 strokes) needed to fire the shot, maybee the 4 blade prop evens that facts of a 4-stroker out? Someday, I would love a 4-stroker for my old `16, and will have to experiment myself. Regards-Jack Graner.
Hank posted 03-23-2001 09:46 PM ET (US)     Profile for Hank  Send Email to Hank     
I'm curious. What's the gear ratio on that 4-Stroke ? That increase in speed with a prop of lesser pitch seems incredible. That aluminum prop must have been exceptionally inefficient. My two cycle 90 HP Evinrude has a gear ratio of 2:1.( That is Tach RPM to Prop RPM.) I run my Montauk with a 19 pitch 3 bladed stainless prop. I max out at about 40 MPH at 5200 RPM. This calculates out to about 87% efficiency at WOT.

Lil Whaler Lover posted 03-23-2001 11:01 PM ET (US)     Profile for Lil Whaler Lover  Send Email to Lil Whaler Lover     
I have been waiting to see if someone would question the reported performance on awares 13 Sport with a 40 four stroke. It has not happened so I have to ask the following question. How much cup and or rake is in this prop? By my calculation awares is achieving 134% of theoretical speed with this set up with a 12" pitch prop.

The numbers reported on the 15" aluminum work out to a very respectable 9% slip and make sense on an efficient hull.

It would take an 18" pitch at 90% efficiency to reach 45 mph. Please help me understand the dynamics of how these reported performance levels are reached.

Thanks, Dave

awares posted 03-24-2001 12:06 AM ET (US)     Profile for awares  Send Email to awares     
Lil Whaler Lover,
As I stated in a earlier post when I started to rig my new Whaler I was disappointed in the hole shot. I am not a prop expert by no means and that is why I went to the very best prop people I know in Texas. I am very fortunate that they are also in Austin Texas.

I am a firm believer that a motor is only as good as its propeller. I am not a engineer, but I am a quality and process manufacturing manager. I expect the finest performance from anything we manufacture and anything I buy. Its true I do drive some of my counter parts crazy, but I am always looking for a continuous improvement.

I do not understand the laws of performance and how you calculate motor to prop ratio. I do understand that I have never gone beyond 33mph in a 13' Whaler until I bought this one. I a sure you that this new rig trimmed out and running 5900rpm on a Power Tech propeller M70 SCBB4R 12 Satin 4 blade stainless on 4 stroke Mercury motor punched 45mph before I pulled it back.

Please contact Power Tech at or Nettles Prop Shop here in Austin and ask them the specific questions on how this can be. Nettles phone number is (512) 837-7707.

Also I do not know the specifics about what you need to know about the motor to help you calculate the expected result. That information should be available on the Mercury site. As I stated I did not believe it myself.

I would love for Whaler and others to perform tests on this prop and others and share the results with all of us. Why is it that the consumer has to figure out a manufactures performance formula.

I also love my 1968 13' Whaler and would not trade it for anything. Each boat has its own identity and feel.

If you are ever in Austin bring your life jacket and will let you experience it up close and personal. It is a sensation better than anything you will get at any theme park.

Please let me know how the final calculation works out.

I also invite any other Whaler folks if you are ever here in Austin please contact me because I would love talking to you about Whaler's and let you drive mine.

Contact me at

Allen Wares

whalernut posted 03-24-2001 06:36 AM ET (US)     Profile for whalernut  Send Email to whalernut     
Allen, that is a most generous offer that you extend you`re hand to other Whalerers! I feel the need to do the same, so if anyone wants to go Whalering with me up on Lake Erie this year, give me a holler at and we can chew the fat and I will give you my phone # there.
I don`t know about you fellows, but I feel as much pride when somebody is riding and/or driving my Whaler in general! My boat is located in Conneaut, OH. 45 min. from Cleveland, OH.- 30 min. from Erie, PA. and I live in Pittburgh, PA. 2 and one-half hours from there, but go to Lake Erie almost every weekend in the summer, and usually take a weeks vacation in June/July. Please let me know, if you want to go fishing(Yeeha) all the better! Regards-Jack Graner. P.S. The Beer is cold!
Clark Roberts posted 03-24-2001 07:20 AM ET (US)     Profile for Clark Roberts  Send Email to Clark Roberts     
Allan, I ,like Dave, am trying to figure this one out... not doubting the results, mind you, just trying to put it together. Your engine has a 2:1 lower unit and at an rpm of 6000 would be spinning the prop at 3000rpm. If prop was 100% efficient (and if it acted as a screw at those rpms - which it doesn't) it would travel 3000 X 12" each minute.. that's 3000 feet per minute or 180000 feet per hour which is 34 miles per hour. Note that a prop doesn't act as a simple screw except at very low displacement speeds, but rather, acts as a non-encased axial flow pump which gathers water from the sides (not the front) and accellerates it as a water jet and it's this action/reaction against the jet that propells boat forward! you can see this jet surface in mid wake behind your boat. A boat cannot exceed the speed of this water jet! Don't want to bore anyone with this stuff but am trying to figure out how these speeds were achived... Allan, how did you measure your speed...with GPS, pitot speedo....paddle wheel speedo..??? Example of other 45mph boats are: Dennis Scott, Sneads Fla has a 17' with 75 Merc (2.3:1 lower unit ratio), 21" pitch ss (stilletto I think) at 5350 rpm, engine up two notches and doel-fin, measured by GPS, calculated 100% efficiency speed is 53mph; my 21 revenge with 135 Merc opti (2:1 lower unit ratio) , 19" pitch Quicksilver Vengence ss prop at 5600 rpm, T&H jack plate/8"setback/4"rise, and doel-fin,measured by GPS, calculated 100% efficiency speed is 51mph. Again, my apologies for boring everyone to death! Help me on this one! I remember when we would measure a distance, put up some stakes as markers and get out the stop watch! Seems as though we were always finding way to trick our rigs out for more speed. Things are the same these days, I'm glad to say, but the stakes and stop watch (and wet note paper and pencil) have been replaced by GPS , satellites.. etc.. who would have figured? Happy Whalin' .. Clark.. Spruce Creek Navy
awares posted 03-24-2001 11:00 AM ET (US)     Profile for awares  Send Email to awares     
I am using a Lowrance X65 to measure the speed. It looks like a paddle wheel assembly. I will be glad to post the GPS results as soon as I purchase one for a comparison.

When I have a few more hours on this motor I will also run it and compare the odemeter feature on the X65 to speed. I just do not want to run the motor at top end for a long period of time.

I am more than satisfied and I am now concentrating my efforts on other areas of the boat.

Whalerdan posted 03-27-2001 10:58 AM ET (US)     Profile for Whalerdan  Send Email to Whalerdan     
I think the answer here is that the prop is "labeled" a 12 but is something steeper. My calculations say it is something like a 16 or so. I don't know that much about props and engines though, so I do not know if it makes sense that a 40 hp motor on a 13 ft boat can swing a 16 prop at 5900 rpm.
Whaletosh posted 03-27-2001 04:56 PM ET (US)     Profile for Whaletosh    
Not to fan the flames but I have qutie a bit of experience with Lowrance/Eagle fishfinders. I have found that the paddle wheel speedos aren't all that accurate. I have had cases where the unit was displaying O MPH even though the boat was moving and the paddle wheel was spinning properly.

Most pitot pickup speedos are very inaccurate; I don't know why they are even installed. I always demand that they be left off. Some pitot pickup speedos are very accurate; namely those designed and sold to waterskiers.

GPS unit provide the most consistent and accurate measurements for most boaters. Their one downfall is at slow speeds. At displacement speeds wind and current will affect the speed measurement. This is because GPS units measure your true speed and direction, not the realtive speed through the water. Keep this in mind when using a GPS for setting trolling speed. Moving 2 MPH upsteam against a 5 MPH current means your lures are moving 7 MPH relative to the water. The fishfinder would read 7MPH if accurate; but the GPS would read 2 MPH. Now you understand some of Einstein's theory of relativity.


Clark Roberts posted 03-27-2001 06:58 PM ET (US)     Profile for Clark Roberts  Send Email to Clark Roberts     
See my comments in "Performance" section under "Performance predictions..." Clark
2001 13 Sport Owner posted 03-27-2001 10:15 PM ET (US)     Profile for 2001 13 Sport Owner  Send Email to 2001 13 Sport Owner     
If you use Clark Roberts calculations on Awares 13 Sport you get the following numbers. The boat and engine gross weight = 580 boat + 205 engine = 805 pounds gross weight. He is using a 40HP Engine/805 =.0496894409___________. The square root = .222911285________. Multiply the square root .22291185_________ X 200 = 44.58MPH. When Clark talks about the boats gross weight I am not sure if he means without passengers or not. Anyhow check my math and let me know if you come out with the same calculations. If Clarks formula is correct, then Aware's 13 Sport does achieve speeds of about 45MPH. You also need to take into consideration that he also used a prop recommended by people who guarantee improved performance. I just recently talked to the JT at Nettles Prop shop and he said he could definitely help select a prop that would get max performance for my boat. Any I really like Clarks formula>
Clark Roberts posted 03-28-2001 06:17 AM ET (US)     Profile for Clark Roberts  Send Email to Clark Roberts     
Gross weight is total weight of boat, engine, fuel, battery, accessories, tools, passengers, etc.... the whole works!!!! Clark
compounder posted 03-28-2001 12:10 PM ET (US)     Profile for compounder  Send Email to compounder     
I suspect that Allen has just failed to measure his speed accurately.

Let's try Clark's formula again:

Boat 580#
(I think Whaler's published weight is just for the BARE hull, not including seating,console,etc., but we'll use it anyway.)

Motor 250#
(Mercury uses short-shaft, DRY weight in their figure of 204)

Battery & Box 50#

Fuel,tank,hose, & fittings 35#

SS, 4-blade prop 10#

Average adult male 165#

Total: 1100#

40hp div. by 1100# = 0.03636
square root of above = 0.1907
200 X 0.1907 = 38.14 mph.

I think that even the above estimated speed is high. I had a really screaming 13 with a 60 hp Yamaha that only turned up about 44mph, and that was super-squirrelly!

I hope Allen will test with a gps unit and let us know actual speed.


lhg posted 03-28-2001 09:07 PM ET (US)     Profile for lhg    
A few observations of my own here. I also use the Lowrance paddle wheel speed/temp sensor as one of 3 speed devices on my Whaler, and checking it against DGPS and a lower unit water pressure speedo, they can run between 5 to 10% high (need to set negative calibration) at speeds of 40mph. So that could be part of the discrepancy.

I have also noticed that 4 blade props seem to require reduced pitch. I notice that Merc's new "Trophy Sport" indicates dropping down one inch of pitch relative to aluminium. My guess is that the 12" stated pitch of awares prop is probably a higher EFFECTIVE pitch than 12".

I would think the boat could do between 38 and 41, with one person aboard. Merc's prop calculator on indicates a theoretical speed, at 1000 lbs, of 41 mph, and 15" 4 blade "Trophy Sport" prop.

But I do believe a 4 blade SS prop makes sense here for overall performance, and Mercury seems to agree with their brand new prop offering for the small gear case engines (30-60HP). I am convinced a 3 blade alum is the poorest solution for any hull that will do over 30, and primarily sold only for cost considerations.

Whaletosh posted 03-29-2001 05:03 PM ET (US)     Profile for Whaletosh    
I have run 4 balde ComProps for years.

Their advise has always been to go to a smaller pitch; so that buttresses what LHG states.


jimh posted 04-02-2001 08:31 PM ET (US)     Profile for jimh  Send Email to jimh     
I have a Lowrance paddle-wheel speed transducer. It shows excellent agreement with my GPS at low speeds. Above about 20 MPH the paddlewheel begins to read proportionately and consistently higher then the GPS indicator.

As Mark Twain said, "A man who owns two watches never knows what time it is."


lhg posted 04-02-2001 09:45 PM ET (US)     Profile for lhg    
To get my paddle wheel Lowrance speed readout adjusted (there is a place where you can adjust calibration positive or negative, by %, on the menu) accurately, I set up the display to show paddle speed and SOG together, making sure I am on open water and not in a current. I have been able to match the readouts almost perfectly. With several of these units experienced, I can say that almost ALWAYS you need to reduce readout by 5% to 10%. After about 40 MPH, accuracy is not so good, as the wheel tends to "float", and the pitot speedo (not much good below 25) and GPS are more accurate.

Another reason it's good to get the paddle wheel readout properly adjusted, is that this function also shows miles traveled (distance log). For this to be accurate, the speed needs to be accurate.

Steve Anderson posted 01-18-2012 04:45 PM ET (US)     Profile for Steve Anderson  Send Email to Steve Anderson     
I'm wondering if the 4 blade Power Tech prop will work on a 2009 Whaler, 13 ft. Super Sport, as the hull may be different. Apparently, this hole shot problem continues with the 40 HP Mercury, as my boat's bow points skyward with wide open throttle, from dead stop. I inquired for exact same prop recommended, but apparently the 12 pitch not available...only a 13 is now listed for sale. If anybody can help, much appreciated.
Jefecinco posted 01-19-2012 09:35 AM ET (US)     Profile for Jefecinco  Send Email to Jefecinco     

I hope things are going well in Harlingen. I remember it well as I spent my first year of school there in 1946, spent many summers there and also went to the 9th grade there.

The speed numbers reported by Awares were not, IMO, accurate. A properly sized four blade propeller will generally improve hole shot but the 45-46 MPH reported in a 13 with a 40 HP four stroke are very difficult to achieve.

We have no idea of your level of boating experience but your hole shot with a load of two people, fuel, etc should be good if your engine trim is adjusted properly for getting on plane. Is your engine trimmed fully in (down) and is the throttle at the wide open position when attempting to get on plane? Those settings will generally maximize hole shot. Once on plane it is usual to trim out (up) and throttle back until steering is easy and ride is about level.

As you gain experience with your boat your actions will become automatic. A bit of practice is always helpful. The front seat is a good place for any passengers you may have with you to help get on plane with minimal bow rise.

If you are an experienced boater please disregard the above.


joedag1 posted 01-19-2012 10:51 AM ET (US)     Profile for joedag1  Send Email to joedag1     
I own a 2011 - 130SS W/ 40hp 4stroke Merc The boat was delivered with a 14"p alu. prop top speed was 34.1 mph GPS I installed a 13"p Trophy sport and gained 2 mph plus a big difference in hole shot.
sosmerc posted 05-30-2012 07:02 PM ET (US)     Profile for sosmerc  Send Email to sosmerc     
Joedag1 I am interested in more performance info with your TrophySport. Specifically, your gear ratio, rpm and speed.
I have been testing Spitfire aluminum 4 blades on my older 15 center console supersport. I have a 1996 F50 Merc with standard gearcase and 2:1 gearcase. Currently running a 10.1 X 15 Pitch and I am still hitting rev limiter at 6200. My main surprise and disappointment is that I am getting around 20% slip at mid-range....meaning I'm only doing about 20 mph at 3800 rpm....was looking for a bit more efficiency. Acceleration is fine. Don't have solid top end speed numbers yet.
My engine is up pretty high (can only go one hole higher) but I am not getting any ventilation...the Spitfire does hold well, as I would think the TrophySport will do as well.
How high is your engine?
Thanks for any info you can provide.
joedag1 posted 06-01-2012 11:00 PM ET (US)     Profile for joedag1  Send Email to joedag1     
My gear ratio is 2:1 , I have not changed the hight of the motor the cavitation plate is even with the keel of the boat .
sosmerc posted 06-16-2012 11:22 AM ET (US)     Profile for sosmerc  Send Email to sosmerc     
Finally got a chance to make some WOT runs this week. Best speed was 36.8 mph @ 6200 RPM. Nice ripple on the water. I was hitting the rev limiter and actually had to back off just a bit to get a steady 6200 rpm.
The Prop Shop in Seattle is going to lend me a Trophy Sport 10 5/8 X 14 to try. They didn't have a 15, but at least I'll get to see how the boat handles.
The Spitfire has good acceleration and handling, but it doesn't seem to be very efficient (too much slip). I'm eager to see if the Trophy Sport has less overall slip in the mid range and top end. If it is not a big improvement then I will most likely get a Vengeance 15 or Silverado 15.
I am pleasantly surprised at the power of this little 4 stroke. I might even be able to ski behind it :)
joedag1 posted 06-16-2012 08:16 PM ET (US)     Profile for joedag1  Send Email to joedag1     
The Trophy sport I'm running is 10 5/8 x 13p = 36.2 mph @ 6000 rpm . I'm no light weight 230lbs. plus gear and bimini. I'm very pleased the way the boat runs and handles .
sosmerc posted 06-16-2012 08:42 PM ET (US)     Profile for sosmerc  Send Email to sosmerc     
That works out to about 19% slip......similar to the Spitfire.
I'll bet you could improve on that by raising the engine at least 2 holes.
When you get a chance, I'd really like to know what your speed is at 3500 and 4000 rpm.
joedag1 posted 06-17-2012 11:21 PM ET (US)     Profile for joedag1  Send Email to joedag1     
Next time I go out I'll get some numbers.
Tom W Clark posted 06-18-2012 11:37 AM ET (US)     Profile for Tom W Clark  Send Email to Tom W Clark     
Instead of resurrecting a 11 year old thread in the POST-CLASSIC section you guys should start a thread in PERFORMANCE where this discussion belongs.

Trust me, a propeller does not know if it is pushing a Classic or a Post-Classic Whaler.

sosmerc posted 06-18-2012 06:33 PM ET (US)     Profile for sosmerc  Send Email to sosmerc     
good point Tom. When I get the results of further testing that's where I will post it.

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