Strange Results from New Bravo LT

[rpr]

I just received a new 22p Bravo LT prop. Mercury is making these upon request, so this is fresh from a Mercury.

I got very disappointing results, not what you would expect based on the results I got with a Bravo XS.

Reducing pitch from 24p (Bravo XS) to 22p (Bravo XT) and I only picked up ~140rpms, and I lost 1 mph top end. The claim to fame for the LT is that is keeps the bow down. My bow was actually kept down better with the XS, which makes no sense. It also feels like it’s cavitating in turns and blowing out a bit at full trim.

I noticed one of the blades has some bad ripples in it. If I can figure out how to post this pic, take a look at this and tell me what you guys think.

[grout-scout]

I thought the lack of belled end was a bow lifter. From my understanding the bell on the xs is to keep from lifting the bow??? Are you certain that you don’t have it backwards?

[rpr]

There’s seemingly conflicting info out there in statements from Mercury Racing that claim enhanced bow lift as well as enhanced stern lift from the flared tube of the Bravo LT. However, the longer barrel is supposed to help keep the bow level and to prevent it from hopping (i.e.: porpoising) as they say it acts like a small trim tab. Example:

“The LT has be known to help with heavier boats such as yours, especially when loaded up with a kicker and gear. It will offer better planing as the flared tube acts as a small trim tab. If you’re looking for more improvement in the lower to mid range, then the LT is worth a shot. However, on top end the flared tube may give too much stern lift...”

[Savage]

A prop can't fix "hopping" and "porpoising", that is a trimming issue.

[rpr]

Props cannot fix porpoising from over trimming, but props absolutely do have an impact on a hull’s tendency to porpoise. I’ve had numerous props on my rig and they all react to trim differently. My hull has rockers which make it prone to porpoise in areas where the next model year has hooks. Known issue with my model year boat that Triton fixed in the subsequent model year, and then ultimately changed the hull design completely and moved the console forward 1.5’ to make the bow heavier and completely eliminate the hull’s tendency to porpoise.

Light bow with rockers as opposed to hooks in the hull = not good for rough water handling. Very difficult to keep the bow down. That’s what the Bravo LT is supposed to “help” do, but there’s no magic bullet that will completely solve this.

[grout-scout]

But if you read the merc racing page about the LT it’s saying the opposite than what you are. I wish yours was a bit bigger in pitch, I’d love to try one out just to see what difference it has on my Champion.


as far as the rippled blades?def seems odd.

[Bullet 20cc]

Two glaring differences between the two props (LT vs XS) is the bell vs the short barrel (no bell). The bell provides stern lift and makes it more difficult for the bow to rise. Best for heavy boats that plow more or boats that like to run flatter with no bow lift...like big heavy center consoles or my Bullet (likes to run flat) . The short barrel (no bell) promotes bow lift by not pushing up on the stern. It is for lighter hulls that like to run on the pad and/or hulls that like to run higher bow lifts...like Allisons, Rangers, Champions, Strokers, Skeeters and Tritons.

Your results make perfect sense for sure. I believe your boat would do better with the XS cuz your boat is not that heavy and likes to run on the pad and even get the bow up while running. It makes sense that you are slipping more in the turns since the LT is pushing the stern up more than the XS which is raising your prop up higher with it...hence less bite on the water. Speed is lower and rpm's are too comparatively cuz the stern lift is keeping your bow from rising which is keeping more of your hull wet (more hull surface to water friction or drag). You should be able to still use the LT but I'm afraid that the size of the bell on back would have to be cut down or off completely to look more like the XS. Otherwise the XS will be the better running prop of the two.

I have done lots of work on my Bravos to get them tuned just right for my boat...so I have learned a lot about them going through that process. They are awesome props and very tunable to your hull...no matter how big or small. Mine look nothing like what Merc sold them as and intended them to be...but they are perfect now.

[mdtritn21]

If you can feel the ripples I'd return the prop to Mercury for a new one.

[rpr]

To oversimplify this, Mercury Racing says a shorter barrel like the Bravo XS settles the stern and raises the bow, while a longer barrel with a bell like the Bravo LT raises the stern and the bow (the whole boat). Since I was looking to lower the bow, and since I have a kicker in my rig (heavy stern), Mercury thought the Bravo LT would work better than the Bravo XS.

Unfortunately, that theory just didn’t work or I have a bad prop. Bullet might be right in his analysis. While the “bell” on the LTs provide stern lift and keep the bow lower which is what I’m looking for to improve rough water handling (my bow rides too high), my results imply that my boat just does not run very well in this manner
amd needs to ride bow high to minimize drag.

Regardless, the prop should not have these ripples in the blade so I’m going to try to return it for a new one.

Thanks for all the feedback.