Bow lift

[T_Huff189]

What props have better bow lift than a tempest plus?

[21XDC]

The Yamaha T1 does. Only fits Merc small shaft and Yamaha.

Bow lift can easily be added to the Tempest if needed...

[digthemup]

What props have better bow lift than a tempest plus?

If you add more rake, you will get more bow lift. Get all your running stats at WOT, and send your prop to Mark Croxton for blueprint and balance. When you fill the form on his site, make it clear what mods you want and why. He will email you back if any clarification needed.

[bb45]

i thought added a cup not rake, it helped my Stratos.

[21XDC]

Rake can help lift, But reduces diameter... If the boat/motor likes the bigger diameter with extra cup, The added rake can be less productive.

[Bandone]

If you want more bow and stern lift without doing a lot of dickin around, just get Mark's Razor 4 XL, my triton got so much lift from a bone stock Razor 4 XL its amazing, mph from a tempest done by mark is almost exactly the same

[digthemup]

Rake can help lift, But reduces diameter... If the boat/motor likes the bigger diameter with extra cup, The added rake can be less productive.

OK, let me clarify, adding rake cupping to the tip of the prop blade. If the cup is on the tip of the blade, the blade has an increased rake angle and a higher bow lift. If the cup is on the trailing edge, it effectively increases the pitch size, and the propeller will create more power at the cost of engine speed-lowers rpm.

[21XDC]

Ummmm No... Rake is the angle of the blade swept back... Nothing to do with cup on tips or trailing edge.

[digthemup]

Prop-Cup-2.png

I hope this illustrates what I said on post #7

[21XDC]

Sorry... Adding cup does not add pitch. It might pull rpms down like pitch, But does not add pitch. Adding pitch pushes the boat forward, Cup does not.

Don't be confused with pitch progression... Some may call that "cup"

[digthemup]

Sorry... Adding cup does not add pitch. It might pull rpms down like pitch, But does not add pitch. Adding pitch pushes the boat forward, Cup does not.

Don't be confused with pitch progression... Some may call that "cup"

Mark,
I know about pitch progressing on the entirety of the blade face, but the picture is right from Mercury Racing 'Prop School'.
Perhaps, they look at it that since cupping reduces slip by holding on to the water longer, hence % reduction of slip theoretically would increase travel distance.

Regardless, I don't want you to think I was being a smarty to your knowledge, but Croxton did add rake cupping to increase my bow lift on both my Trophy and Tempest Plus.
Be well and stay safe.

[digthemup]

Mark,
What is your experience in running setups for 25"p Trophy Plus B&B by Croxton with extra rake cupping using ring exhaust and solid PVS? or no ring large hole PVS?
Mark just said keep playing with it, and I am hoping to cut some dial time.
Thank you in advance.

[XingEyeballs]

I’m by no means prop savvy but I sent in the prop on my last boat and added cup to the blades and cleaned nicks. Prop held the bow much better at all speeds and had little to no RPM or top end change. Great information Mike, thanks for sharing!

[21XDC]

MIKE,
What is your experience in running setups for 25"p Trophy Plus B&B by Croxton with extra rake cupping using ring exhaust and solid PVS? or no ring large hole PVS?
Mark just said keep playing with it, and I am hoping to cut some dial time.
Thank you in advance.

I'm Mike

I try to never use a cav ring. It blocks exhaust, and I have seen HP and speed loss from the restriction. I prefer to leave the cav ring off and use the PVS plugs to adjust... If you cant reach the goals, Then use the cav ring as a last resort.

[digthemup]

I'm Mike

I try to never use a cav ring. It blocks exhaust, and I have seen HP and speed loss from the restriction. I prefer to leave the cav ring off and use the PVS plugs to adjust... If you can't reach the goals, Then use the cav ring as a last resort.

Sorry Mike for trying to change your name.
My '02 Cobra 201 DC running a '03 Merc 225 EFI worked, off 10" Slidemaster 2 7/8" P to P currently has around a 7 sec holeshot without ring and full PVS WOT 56-5700ish upper 60's with occasional low 70. Only thing that sometimes if I trim up bit fast during holeshot, may get a quick blowout/grab again at bow over. That's when I reached out to Mark, but he said not to be concerned and play around with PVS/ring set up. Don't seem to do it much, especially with the Tempest Plus, which is set up with large hole PVS.
Can't do much right now, all lunches are closed in NYS, unless you have your own private 1.
Be well Mike,
Frank

[21XDC]

[MaverickPro201]

Good info Mike

[1Holeshot]

Mike and Frank, I appreciate your posts and the images help me comprehend what your posts are saying.

The 4-7 image reminded me of the weed/line cutters on the old 28" Chopper props I used to run. Local prop guy would cut them off if you requested it.

[Bandone]

I'm Mike

I try to never use a cav ring. It blocks exhaust, and I have seen HP and speed loss from the restriction. I prefer to leave the cav ring off and use the PVS plugs to adjust... If you cant reach the goals, Then use the cav ring as a last resort.

I didn't think that prop venting with a ring or not would change top end, I have always thought it was just for holeshot, but it makes sense getting the gases out faster will get you up on plane quicker but top end how ? I might try going that way and see if there's any difference, I'm happy with what I have but another couple on the top end would always be nice

[21XDC]

I explained the HP loss from the restriction of exhaust in the quote. You generally loose speed with less HP.