Help with my new boat

[muskiemike12]

I just took my new 2018 Tracker Pro Guide V 175 Combo out for the first time. I did the break in properly on the Mercury 115 4 stroke. I have 7 hours on the motor now. It came with a 17” black max propeller. Wot rpms are 5200 with a light load. 1/4 tank of gas and me. Heavy load I can’t hit 5000 rpms. The boat weighs just over 1900# on the light load. Hole shot is good and top speed with a light load is 38 mph Heavy is 32 mph. Can someone help me chose a new prop to get my rpms up closer to 6000 with a light load. Thanks!

 

[Sea Rider]

Will you be constantly shifting load from light to heavy loaded ? A fixed load is much better and faster to dial a top prop.

Same black max prop with 15 pitch should put OB close to stated wot rpm when lightly loaded, will need a water test to check that out. Bear in mind that when adding extra load wot rpm will drop accordingly.

Happy Boating

 

[muskiemike12]

Yes, unfortunately the difference in loads will be an ongoing thing. I do have a 4 blade Rubex 13.25x13 that i plan to test with next weekend. I might end up switching props as need be. If i went with a stainless like the Titan would i turn more rpms than the aluminum black max?

 

[Sea Rider]

What's the min-max wot rpm range factory stated for that engine ? If 6 K is the max wot rpm range, why would you like to prop it right to achieve that rpm when lightly loaded ? I see this scenario : When engine is propped right to run say max wot rpm range lightly loaded when over loaded max wot rpm will drop towards the middle or even to the lugging side depending on how much load was added.

Better will be to prop it right for engine to rev towards middle wot rpm range when middle loaded, that way can play with wot rpm and load up or down much better and safer for engine.

Yes, shifting loads is a big issue for any given boat/engine combination and will be bored very soon if need to shift props for engine to run middle to max wot rpm range factory stated when playing with load, that's if you like boating on plane rather that going just for fast displacement speeds. In cases where load varies so much a variable pitch prop will be the way to go, but are expensive if they are still being fabricated. Load is a serial rpm killer LOL!

Is the current installed prop a 3 or 4 blade one ? Will need to make a water test on flat calm water cond to test the other 4 blade Rubex and check which rpm achieved to compare performance with current one if it's a must pick one between both.

Happy Boating

 

[muskiemike12]

Recommend range is 5000-6000. Current prop is a 3 blade 13.5 x 17. Will a vented prop like the hustler increase my rpms or is that just for hole shot? I will post my results after testing.
Thanks!

 

[Sea Rider]

Impossible to know on a theory basis, a wot water test will tell. Post wot results if testing the 4 blade Rubex, will be interesting to know which rpm was achieved when lightly and fully loaded.

Happy Boating

 

[WesNewell]

With a 17p prop, you should be turning 6000rpm with such a light load. My guess is that the engine is mounted way too low causing tremendous drag. Specs on the boat are 1525# dry weight. With 400# people and gear and 8 Gal. gas, recommended prop is a 19.48P prop turning 5500rpm @ 41 mph.at a total weight of 2330#. A 17P prop is recommended for 1000# people and gear with 25 gal, gas for total boat weight 3030# @ 5500 rpm and 35.7 mph. Having just gone through some reseacrh on factory mounted engines, one of my own, and my brothers 4 year ols ranger, and looking at some trackers at a dealership, all were mounted too low in the water. Raising mine just 1.5" increased mt speed by 10%. From factory prop/engine postion I went from 31 mph to 38 mph with smooth ride to over 40 mph with some porpoising on 1 1000# boat and 60hp 4S.

 

[Faztbullet]

Are you using the trim????

 

[muskiemike12]

Yes I’m using the trim. I trim up until the prop ventilates then down a hair. So I’m totally trimmed out. It doesn’t look like the motor is mounted too low. It’s a deep v so if I look at the anti ventilation plate it’s slightly above the bottom of the hull.

 

[Sea Rider]

Why is it that near everybody here likes to trim up, trim down excessively when under way from the hole. Have read tons of Owner's Manuals from near every OB manufacturer. The general consensus for recreational boating with hydraulic trim OB's is :

-Distribute weight, passengers weight evenly on deck.
-Trim OB one less setting from neutral position.
-Apply throttle, once combo is on plane, trim back to neutral for combo to ride parallel to water level, same position as when combo floats by itself.

If we add to this formula :
-OB sitting at the sweet OB/transom height for water flow to skim right under upper splash plate at plane.
-A maximized prop for OB to rev towards max wot rpm range factory stated as loaded,.

Won't need to play with trim nor move it from neutral position at all. The hole shot with instant plane that will be achieved if stated 5 points are dialed spot on is a day/night difference compared to doing nothing, that's boating as you have been doing so without knowing the extra boating fun you're missing.

For this scenario to happen need an OB in excellent running shape. Same principles applies for manual trim OB's with same excellent results.

Try this suggestion and report if went much better than before..

Happy Boating

 

[Faztbullet]

Sea you need to watch the video below as you have no idea about what your talking about when it come to power trim,its usage and effects.

https://www.youtube.com/watch?v=ljJ2nB3sA60

 

[WesNewell]

If you've got a 4" jack plate, the av plate should be a couple of inches above the bottom of the hull. Maybe higher on a V hull. With the engine mounted at the proper height, you shouldn't need to do much trimming at all with balanced load. Trimming an engine up that's mounted too low to begin with just causes porpoising.

 

[Sea Rider]

Sea you need to watch the video below as you have no idea about what your talking about when it come to power trim,its usage and effects.

Come on don't make me laugh. That video doesn't say a thing as we don't know if that large OB sits at the sweet OB/transom height which is the first thing you need to consider, check and modify if needed to start with. If OB sits at any other height than the sweet spot need to play with the trim button, worse if you don't care all about correct deck weight distribution for a fast hole shot.

If any OB sits at that precise transom height spot what described works spot on, the issue is that nobody knows, cares about it, all go rigging their boats like zombies per the idiotic rule of thumb that states AV plate even with aft hull bottom which ain't so as each OB brand has it's own particular height to consider which is stated in every new OB Owner's Manual. independently of its size and HP.

Hey Fazt, should have passed that video link to the OP instead than to me. Let's let the OP test what's been suggested and report back his findings. He's the one interested in solving his boating issues, independently of out boating disagreements that we often have.

I once made this question : how do you know this OB sits at the sweet transom height spot to a Yam techie with 20 years of experience rigging boats, his answer was : Yam always manufactures their OB's to work properly. So if you like sitting your OB on top transom and boating that way while playing excessively with the trim button be my guest...

Happy Boating

 

[jimmbo]

The video only mentions trimming out until Ventilation occurs. It should have also mentioned trimming out until porpoising occurs then trimming in till it stops.
Max trim will be affected by engine mounting height. Higher heights will of course ventilate sooner, and will also reduce bow lift as the leverage is reduced.
I put very little faith in the ‘best performance is when the prop shaft is parallel to direction of travel’ statement. Almost all boats appear to get their best speed when the Trim is higher. Exceptions to that would be with very high mounting heights where with any positive trim the prop would blow as it is already running 1/3 - 1/2 out of the water
Regarding optiminal engine height, it varies with hull and/or prop choice and top speed potential.
While Yamaha may very well manufacture their engines to work properly, that 20 year rigger has his head up his behind, because not all boat manufacturers build their transom identically.

 

[jimmbo]

Since it is new, take it to the dealer to verify the tach is accurate, and that the carbs are opening fully. Going to a 15 will probably add 400 - 500 rpm.

 

[muskiemike12]

I did hit the rev limiter fairly easily with the 13 pitch 4 blade with a light load. I could trim up higher and got more bow lift than I did with the 3 blade. I was running at 34 mph at 6000 rpms. Hole shot was very quick. Fully loaded with 900# of extra weight over the light load I was still able to hit 6000 rpms and 33 mph. I ordered a turning point 4 blade 15 pitch. Hopefully I’ll get to test that out next weekend.

 

[WesNewell]

Did you verify the tach was set right? long story short, my bother has a 2015 ranger rt188 with a 115 optimax on it. He was turning 6200-6300 rpm with a 20p laser prop. Ran it like that until last year when we discovered the tach was in the wrong setting from the factory. Set properly he was maxing out at 5600 rpm. A 15p prop on that boat will be way under proped imo. First thing you need to do is find what the proper setting is for your tach for your engine on line and then verify it's set right. Check engine mounting height with bottom of hull and av plate, and if you hull has a center stringer about an inch wide and deep, don't count that as the bottom. The bottom is the flat part just to the side of that. If you have a jack plate on the boat, add about 2 inches of rise for a 4" jack plate. And I'd still bet your engine is mounted too low.

 

[muskiemike12]

The tach is set right. The rev limiter hits in at about 6100 rpms. Motor is mounted at correct height. The av plate sits about 3 inches above the bottom of the center stringer. This is a very deep v. The flat spots are at the reverse chines on the sides of the boat. There is no "pad"

 

[WesNewell]

6100 rpm with a 17p prop sounds about right with light load. And that's to0 high and why a 19.48P prop is the recommended prop for a 400# load with 8 gal. of fuel, and a 17P prop is recommended for 1000# load with full fuel tank. Personally, I'd go with a 19p peop unless you carry a heavy load most of the time and then I'd stick with the 17p prop you have or go to a ss 17p prop. to check engine height, trim engine with av plate level with hull, get to full speed and then lok at position of av plate to waterline, It should not be below the water line. If it is the engine is mounted too low.. If you need to adjust engine, I'd recommend an adjustable height jack plate, they can be had for <$200.

 

[Sea Rider]

Making any boat to perform top is a nightmare. There are too many tech variables to deal with such as hull design, drag coeficient, engine height, transom angle, trim angle, prop, load, and personal boating tastes and tricks.

In plain agreement with Jimmbo, as we have seen all boat transoms are not built with exact same heights doesn't matter if being short or long ones, varies from manufacturer to manufacturer. Will add that same applies to outboards, all brands vary in lower leg lenght between them no matter is being S, L sizes.

Regarding the high tech illustration, asked the questsion soon after he finished installing a brand new 60 HP Yam on a boat. Owner was not happy with combo performance, so he asked my opinion. Went on a wot water trial on flat calm water cond, visually checked what was going on at back transom, OB was found sitting to high and prop aerating on close turns or at choppy windy water cond. To correct prop aeration a bit, OB was trimmed down.

With those parameters my fiberglass techie chopped 1 1/4" transom down. Bingo, now combo performs top on all water cond while water flow at speed skims right under upper small plate while at neutral trim. That's why I don't believe in those big shots "expert riggers"" that sits engines on transom and don't care after collected their money if combo performed OK once running on water which is a different and much more complicated story from a dry installation one.

Happy Boating