Prop/Stern Lift???
 

What prop should I try if I want to increase stern-lift? Seems like everyone likes props that increase bow-lift but my boat seems to prefer some stern-lift for top mph.....I am running a Michigan Ballistic which works better at mid-top end. The Mirage planes and accellerates better to about 3500 rpm's....

"Bad-Habit"

If yours has a hook like mine, it would seem it would like bow lift more since the hook is keeping the bow down. I just sent a check for a 21 cleaver to try on mine. I have a 23 cleaver on it now.

Wow; this could be a long talk. In general "cleaver" props develope the most stern lift. Merc. Mirage will give you the most Bow lift. However, there is NO prop that will compensate for a hull problem. BEFORE YOU BUY MORE PROPS, CHECK OUT YOUR HULL!!! Been there-done that!! --- Jer

Now, I'm going to try to make this easy. Just like you can't tune out bad compression on #7 cyl. by adjusting the carb, you can't fix a hull problem by changing props. --- Jer

Well Jp me and "Cuda" have the same hulls. Our Formula's have a "hook" built in. A dead cylinder is probally not a good comparison. I think it would be more like a how some race cars have more down-force than outhers. The built in "hook" provides a more stable ride than some outhers but at the expense of top-end. Wouldn't a hook cause the stern to squat. I would think that "bow-lift" is worthless if you can't get the ass-end loose. Hell isn't it kind of like a stepped hull vs. a non-stepped hull? A cat vs. a deep "v"?

"Bad-Habit"

I'm going with the cleaver because I have been told it will minimize the heeling to port. I haven't really tried out the 23 cleaver that is on there, but when I took it out with 4 people and a full tank, it was a ***** getting on a plane. Now that I have another boat coming, I can afford some down time on the 20, so I might try to take the hook out of it myself. I know I can float a wavy floor out enough that you can sit a marble anywhere on it and it won't roll.

A hook in the hull will cause stern lift. You need a prop with bow lift to compensate for the hook. A 4 blade prop will generally provide more stern lift than a 3 blade. Sounds like you need something like a 3 blade Mirage+. Also, more cup in the prop will cause stern lift, too. This has been my experience.

Cuda, you don't have tabs to compensate for "Heeling"??. Man, we are going to start from the very beginning here. But I can tell you this: When it is all set up right , at WOT the tabs are UP and the boat "HANGS" in the air. About 2 sq. ft. of the a$$ wetted. I cuold send some pics if I need to prove this. --- Jer

Just my 2 cents guys.>> I repowered a 208 Baja Islander with a 502 (500 hp) and had some serious handling problems. I admit some of the problems are in the hull but>>> I tried the whole gambit of Mercury props, Mirage, Vengenance,Bravo I, Trophy, and Lazer II. The prop that worked the best for me was the Laser II. I know it's a prop mainly designed for outboard bass boats but if you want to get the bow up you need a high rake prop to push the stern down ,small diameter 3 blade worked better than 4 blade, smaller diameter worked better than large. If you can get your mitts on one try it Again just my 2 cents

syringa:) :)

I misread the post i thought you were speaking of bow lift.

syringa

Nope, no trim tabs. I may put them on, but as pointed out, it will slow the boat. The strange thing about it is the boat didn't heel before I repowered it.

The only thing that I can think or here is that if more HP created a "heeling" problem then the hull problem (hook) really needs to be addressed. I found that with my hull when it had the hook the addition of more power only made the "plowing" worse and yes; without the use of tabs the hull wanted to lay over. Probaly not what you wanted to hear but "been there; done that", I'm sorry to say. Good luck. --- Jer

If your boat has a hook built in to it then the last thing you need is stern lift. The hook pushes the stern up and the bow down. Just like having tabs in the down position. If you try a prop with more stern lift it will make this condition worse and the boat will tend to bow steer. Look for a prop with more bow lift. Every prop is different but here are some general rules.

More blades cause more lift.

Pointed cleaver style props generally cause stern lift.

Round ear props generally cause bow lift.

The more rake the prop has the more it will lift the bow.


So you should be looking for a highly raked 3 or 4 blade round ear prop that will give you the bow lift need to overcome the hook in the hull. This will get more boat out of the water and you will go faster.

Mercury Marine and or Quicksilver used to sell a book titled "Everything You Need To Know About Propellers" or something close to that. It explains the general principles involved in prop selection.

The only way to know for sure which prop is right for the boat is to test as many as you can.

Ron

Im in the same boat with the built in hook ( in know, not funny). My problem is worse as the drive is an OMC so trying props is a pain. I have a dealer who is willing to change hubs on the new Merc props so I can try them. Does anyone know what it costs to rehub a Merc prop... in case I find one I like I can look for a deal on a used one? I remember somthing about Merc props being sold under another generic name through non-Merc dealers. The price difference was considerable. Does anyone have that info?

Syringa.. i send you a couple emails to the add. listed in your profile. I was just checking to see if you got them. sj