Bob's nose cone = not a good choice?

[croSSed]

I just sunk $1000 + into a beautiful Bob's nose cone, and I'm disappointed. Here's where I was, and where I'm at.
Where I was:
2.4 175 on a 17' Cee Bee Avenger Mach II, all solid mounts, Sea Star hydraulic steering, stock 2:1 lower with the top three holes plugged, jack plate up as high as it would go before sucking air, 28P big ear Chopper, 78 mph at 6400 rpm, about 8% slip.
Now, same rig, same prop:
2:1 coned by Bob's, was able to get the jack plate up about another inch (see pics). 72+ mph, 6600 rpm, about 18% slip.
Not what I was hoping for. I have a couple options I think: Buy some set-back plates to mount the motor higher on the jack plate (there's no way now to get the plate or motor any higher; they are both as high as they can go) to take advantage of the LWPU and scrub drag from the extended lower. MAYBE I can reclaim the speed I did have. The other option I have is to swap the nose coned lower for a spare stock 1.87 lower to see how that performs with the chopper. I do not like the idea of adding set back plates to the jack plate as I'd be adding more weight to the transom, and giving more leverage to the motor against the transom, which is already a little stressed. There are some slight stress cracks in the gelcoat at the transom that started to appear after installing the jack plate. One of the other things I'm thinking is the 2:1 lower is now coned. It's permanent. If I don't like the way the 1.87 lower performs with the Chopper, as in, I'm getting something less than 78 mph, I could have all the gears swapped out. Turn the Bob's lower into a 1.87, and the stock one into a 2:1. Then, sell the 1.87 lower. I'm calling Bob's tomorrow (Monday) to get their thoughts.
I would appreciate your thoughts. Thank you.

Sorry about the upside down pics. This site just will not let me post pics properly. They are oriented the correct way on my computer, but they won't post properly here. I even tried turning the original pics upside down to see if they'd post correctly. They would still post here upside down.

[skialot2]

You are right on the verge of needing a nose cone. They do slow you down when you add them. But you can go faster with them. Looks like you are about 2" below the pad. If you can jack up the motor more, you may get the speed back. But that may not be easy with your boat. Looks like you really need a 15" mid. But they are not cheap.

It looks like you have a washer between the wedge and the motor mounting bracket. That can break the bracket. The bracket should lay flat on the wedge.

[XstreamVking]

IMO The longer gear case is increasing stern lift, pushing the nose down. ( I see a lot of trim in your pic) Your boat likes a chopper, that says it needs the bow lift to run good. On most rigs the longer gear case only works to your advantage above about 80 mph and raised sky hi.

[croSSed]

You are right on the verge of needing a nose cone. They do slow you down when you add them. But you can go faster with them. Looks like you are about 2" below the pad. If you can jack up the motor more, you may get the speed back. But that may not be easy with your boat. Looks like you really need a 15" mid. But they are not cheap.

It looks like you have a washer between the wedge and the motor mounting bracket. That can break the bracket. The bracket should lay flat on the wedge.

A 15" mid is off the table. Yes, there is a washer there. I installed those because the angle wedges were keeping me from getting the up-trim I wanted. I didn't consider that it could break the bracket. That would be bad. But, I like the down trim the wedges provide. Makes it great for skiing or hauling a load. My boat has trim tabs because it has a tendency to porpoise. Even with the tabs it would still do that when I was loaded down, so I added the wedges. Problem solved. I've been considering having a custom jack plate bracket fabbed, the part that the motor bracket bolts to, a bracket that's maybe 5" longer and has slots that would allow about 4" more up travel. But then I'm worried about moving it out of the operating range of the lift motor/pump. Which begs the question, does the motor/pump HAVE an operating range, or will it just continue to lift until the stop bolts on the plate stop its travel?
I have a lot of seat time in this boat, and FOR SURE it needs a lot of bow lift to get its best top speed. This Chopper is the best speed prop I've tried on my boat, and I've tried over a dozen of them.
I talked to Bob's yesterday. I talked to someone named Robert (Bob himself?) and he was SHOCKED at my situation. He really didn't know what to say other than that it SHOULD be faster - sharper leading edge, sleeker design water should flow over it better, etc. I suggested that the length of the torpedo now might be the problem, that it now has more surface area to cause more drag. He rejected that idea. Beyond that he was at a loss.
I wonder if the wedges are creating an angle that in essence shortens the up travel? Thoughts?

[Jim Speros]

The wedges absolutely take away from how far engine can be trimmed out. I am not familiar with your boat and don't know specifically whats best. I do encourage you to do your own testing and not rely on third person hearsay. There are so many variables in a set up and driving ability.

[skialot2]

I would get rid of the washer. It can't make that much of a difference in trim angle. If it's that necessary, I would shave down the wedge angle. I have had a bracket brake while running. On an Evinrude, not a mercury. But it is not something you want to take a chance of happening.

The lift ram and the bracket are usually designed with each other in mind. If you make a bracket with longer slots, the lift ram will run out of travel. But I don't think you need more travel. You just need more height. If you can find a jackplate where you can get the propshaft level with the pad at full height, when you lower the plate, you should be plenty below the pad for a holeshot to ski off. I also think getting the motor higher will help with the purposing. I also think you won't need to trim as high to go fast. Right now, you need to over trim to get the gearcase out of the water to get the best speed. If you jack up straight up, you should get more bow lift with less trim. You should run faster with a more level gearcase. Making the gearcase run through the water at an angle adds a lot of drag. The fastest boats run with level or slightly negative trim. Look at the gearcase angle in this picture.



I don't know why Robert (Yes, I believe that is Bob himself) would reject that more surface area causes more drag. It definitely does. I lost a nosecone off one of my lowers. So, I added a transom mounted water pickup. No other changes. Same lower unit. Same prop. Same propshaft height. Same trim angle. Boat was 5 mph faster without the cone. From 65 to 70 mph. Problem is if you start going over 80, without a nosecone, you going to have a blowout.

[NICE PAIR]

I just sunk $1000 + into a beautiful Bob's nose cone, and I'm disappointed. Here's where I was, and where I'm at.
Where I was:
2.4 175 on a 17' Cee Bee Avenger Mach II, all solid mounts, Sea Star hydraulic steering, stock 2:1 lower with the top three holes plugged, jack plate up as high as it would go before sucking air, 28P big ear Chopper, 78 mph at 6400 rpm, about 8% slip.
Now, same rig, same prop:
2:1 coned by Bob's, was able to get the jack plate up about another inch (see pics). 72+ mph, 6600 rpm, about 18% slip.
Not what I was hoping for. I have a couple options I think: Buy some set-back plates to mount the motor higher on the jack plate (there's no way now to get the plate or motor any higher; they are both as high as they can go) to take advantage of the LWPU and scrub drag from the extended lower. MAYBE I can reclaim the speed I did have. The other option I have is to swap the nose coned lower for a spare stock 1.87 lower to see how that performs with the chopper. I do not like the idea of adding set back plates to the jack plate as I'd be adding more weight to the transom, and giving more leverage to the motor against the transom, which is already a little stressed. There are some slight stress cracks in the gelcoat at the transom that started to appear after installing the jack plate. One of the other things I'm thinking is the 2:1 lower is now coned. It's permanent. If I don't like the way the 1.87 lower performs with the Chopper, as in, I'm getting something less than 78 mph, I could have all the gears swapped out. Turn the Bob's lower into a 1.87, and the stock one into a 2:1. Then, sell the 1.87 lower. I'm calling Bob's tomorrow (Monday) to get their thoughts.
I would appreciate your thoughts. Thank you.

Sorry about the upside down pics. This site just will not let me post pics properly. They are oriented the correct way on my computer, but they won't post properly here. I even tried turning the original pics upside down to see if they'd post correctly. They would still post here upside down.

[croSSed]

FOLLOW UP: I found a stock 2:1 lower at a salvage yard, good price, had it painted and plugged the top 3 holes, and I'm back to where I was, which is good. Anybody want a basically new Bob's coned 2:1 20" lower?

[KIRCHNER]

your first post, u raised the motor 1'' more, and more slip w/ cone. why not put it back where it was before the cone? with the low slip #s?

[croSSed]

I don't understand...
I had to put this Bob's lower back on because my other two stock lowers took dumps on me in two week's time. The 2:1 now won't shift and stay in reverse gear; it's at the shop waiting on a repair. The 1.87:1 which I put on as a spare so I could get on the water, the pinion nut came loose. So I had no choice but to put the Bob's lower back on just so I could get on the water. I went out to the lake and did a 77 mph run at 6600 rpm! Now I'm working on fabbing new transom plates for my jack plate that will raise the engine 3". Pics to follow probably on another thread.

[skialot2]

You are probably running it at a better trim angle this time. When you over trim with a nose cone it adds a LOT of drag compared to over trimming without a cone.