Bow Lift

[JFZ]

What prop would have better bow lift a Tropy Plus or a
Tempest?

How would motor height affect lift?

Thanks for the help!

[REW]

The Tempest Plus has a heavy rake angle which equates to a lot of bow lift:

https://www.mercuryracing.com/prop-s...-3-blade-rake/

https://www.youtube.com/watch?v=bBE15dmC6cs

The trophy plus also has a very high rake angle that leads to excellent bow lift.

https://e-ribbing.com/en/propellers/...teristics.html

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I expect that the biggest difference is that the tempest is a 3 blade prop and the trophy is a 4 blade prop.

Try one of each in 4 different pitches each and see which ones work best for you.

You can theorize all day long, but the only way to know for sure is to put on the first of a dozen props and use each of the dozen props on a test day and get information for your rig, load and motor.


And - info:

https://www.youtube.com/watch?v=1e27rk-byOI

[Ltrain]

Always been able to get ample bow lift from a Mercury high 5 prop

[SLE]

One of the best bow lifting props is the Tempest, it's the reason that prop is so popular. if anything will get the nose of your boat up, a tempest will. It however doesn't offer much in the way of stern lift and sometimes can be too much bow lift which makes bow control in rough water difficult as the bow will hang up as you come off a wave causing the boat to slap down on the next one instead of cutting through the next one with the nose. The Bravo FS would probably the next best but will provide better control and some additional stern lift. The Rev 4 will provide the best whole boat lift from stern to bow and definitely offers the best control, it will likely cost you a few mph on the top end as it's a big wheel to turn and usually run a couple hundred rpm than other props of the same pitch.

Can't say you here much anymore about the trophy anymore since the merc reinvented the bravo and came out with the Rev 4. I tried a trophy several years ago and can't say I was impressed with it, ended up with a Tempest on that particular boat with a high-five as my back-up prop. The trophy kinda had that sling shot effect where it would spin a ton of rpm at take off but really wasn't grabbing a lot of water to move the boat untill the boat picked up speed. was terrible for working rough water. it was also a heavy boat.

If you post your boat year & model, engine, and what you get now for speed and rpm you will probably get the best help dialing it in. should also include what your trying to accomplish for performance goals; ie, top end speed, hole shot, overall good performance, slow planing speed, etc etc ect.

[JFZ]

I have a Lowe 1710FM and a 115hp CT Mercury. WOT is 32 mph at
5800 rpms. It seems like the boat is a little low in the water
especially the bow. I can't move any weight back.

Currently I'm using a 21 pitch Trophy Plus. The motor should be faster.
There are some waves in the hull 1/16th is about the biggest but that sure can't be any good. At $600 I can't afford too many props to try out

I just put solid plugs in the pvs holes I don't like the handling with the vents.

Trying to plane at a lower speed is impossible.
I was thinking maybe a little more lift would help and filling the pvs
should improve the lower speed planing.

I'll probably get out on Mon. or Tue. I'll Give the results.

[muskyed]

Something is not adding up with your prop pitch, rpm's, and speed. With a 21" trophy at your rpm's, you should be 50 mph plus. Are you sure your engine is not mounted too high, and you are not getting massive prop slip? Just as an example, on a second boat I had a few years back, Lund 1775 Pro Guide with 90 hp mercury and a 17" spitfire prop, I think I was about 5600 rpm and 43 mph. Thats with a boat about the same size, less rpm, 4" less pitch, and less HP. It looks as though someone put the wrong prop on and raised the engine too much to try and get the rpm's back. You need to worry more at this point about the correct prop pitch and engine height. Bow lift is somewhat meaningless at this point untill you can correct your other issues. Not sure what engine a CT version of Mercury is, but if it is a 4 stroke, you need to drop your proppitch first by at least 4". Also if it is one of the newer 4 strokes The Mercury Spitfire props are a fantastic prop. Tempest props are great for bow lift, but keep in mind that most boats correctly proped for a 21" Tempest prop, are running the high 50's to about 60 mph. Bow lift for now, is not your problem, the correct pitch prop and correct engine height is. The fact that you can't plane at slow speeds,also points to the wrong prop and or engine height.

[JFZ]

It's a four stroke with command thrust. A 150 horse lower and a
2.38 gear ratio. A 19p trophy just spins and over revs.

The hull does have some waves in it. The slip is about 30 on Mercury's
slip calculator.

On the bow is a 112 lb thrust trolling motor and 3- 29 series batteries and
on board charger mounted almost even with WT windshield.

I was thinking too much weight up front and plowing or maybe it's the hull
waves. The welded seam on the back of the transom doesn't. help either.

Thanks for the replies.

[muskyed]

How high is your cav plate in relation to the bottom of the hull when your boat is on the trailer and motor trimed level? If you are above the bottom of the hull, lower the engine and try the 19" again. A 30 slip factor shows the engine height, and or prop is wrong. That is massive amount of slip. A slight increase in bow lift with a different prop is not going to correct the other setup issues you now have. While a Trophy prop may not have quite as much lift as a Tempest, it should easily carry a trolling motor and 3 batteries on a 17' boat.

[JFZ]

The motor was in the highest hole, lowest down it would go
when I ran the 19 pitch.

The 21 pitch I am currently running in the second hole from the top.

The boat is 17' 10".

[Ltrain]

Originally Posted by JFZ

It's a four stroke with command thrust. A 150 horse lower and a
2.38 gear ratio. A 19p trophy just spins and over revs.

The hull does have some waves in it. The slip is about 30 on Mercury's
slip calculator.

On the bow is a 112 lb thrust trolling motor and 3- 29 series batteries and
on board charger mounted almost even with WT windshield.

I was thinking too much weight up front and plowing or maybe it's the hull
waves. The welded seam on the back of the transom doesn't. help either.

Thanks for the replies.

That shouldn't be too much weight up front- I have 4 series batteries, a dual pro 4 bank charger under my bow deck and a 72" trolling motor on the nose and still get good bow lift running a 19p high five with my Yamaha f150.

As was stated you might have to correct motor height