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Discussion Starter · #1 ·
I bought this boat new in 03, when I put in the water for the first time, it blew out real bad about 5100 rpms, maybe 5200. 20" four blade ss prop. The dealer gave me a 18" 3 blade ss, that sent the rpms though 6000 rpms when it blew out. I think the correct term is ventilation. I put the four blade back on with some added cup and this improved it a little. Then we dropped the motor on the transom, all the way (1"), this gave the biggest improvement, but still blew out a little. So I cupped the prop some more and it went away, but at a loss or rpms. The boat runs 49 mph with a light load 47 with a normal load. I have been told the cavatation plate needs to be within an inch from the bottom of the hull. Now the problem is I am about 5". They tell me the transom is keyed and the cavity fills with water and feeds the prop. I can't drop the motor any more so what do I do. Repitch the prop jackplate to lower the motor or both, mpg suck. Bluewave 213 Pulse 150 vmax. I know there is more speed and mpg if it's right.
 
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Discussion Starter · #3 ·
I just registered on that forum and I guess it will take a while to let me on. What does he mean by motor 1 3/4" above pad or 2 1/2". I think that is where my problem is, motor heighth. I never should have took delivery of it. I do like the boat but this needs to be fixed. Not to much help from Manufacturer, and no help from dealer.
 

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Roll Tide!
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A couple of thoughts. I have a 23' Fishmaster that has a similar hull and transom design as the Bluewave. I have a 200 hp Johnson with a 19" 4 blade, hydraulic jackplate with a 4" setback, and a Nedski foil compression plate. It's setup to optimize my shallow water performance not top end. WOT is 46 mph, but it get's there quick. Without the Nedski, I start to get cavitation when the jack plate is about 2" from the top. With the Nedski, I can run it all the way up with no problems. A compression plate and a hydraulic jack will solve your cavitation problems, but the plate adds drag which will cost you a couple of mph.

However, if maximizing your top end is your goal, I would start with a call to Baumann's. They can usually solve these problems with the right prop setup.

Also, how are you trimming it? That type of hull doesn't need to be trimmed all the way up. Mine runs best with a neutral to slight up trim depending on conditions. If I trim it up too far, even with the plate, I get cavitation.

BTW, 49 mph on a 21' boat with a 150 sounds pretty fast to me.
 
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Discussion Starter · #8 ·
Alright lets hit the high points, I once had a 21 Kenner that ran 62mph @5800 rpms with a 200 Johnny, no JP or 4 blade prop, just 21 inches of pitch, it didn' t cavitate,or vent,it just ran the way it was supposed to, just like all other boats I've had(5). I have no jackplate, My cavitation plate is 1.5-2.0 " above the water line at speed. No tunnel straight vee bottom and as far as speed , if the motor can run at optimum rpms without some much cup in the prop, this should be the most efficient setup. Cupping the prop is treating a symptom. The problem is venting. Not speed, or lack there of. Why is it venting? Is the motor to , did they put the wrong motor on just mine . It's a 20 " shaft. Top of transom to bottom of hull is 25".
 

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Ankle Deep Custom Rods
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3,467 Posts
a 20"shaft on a transom height of 25" doesn't sound right to me. I think you might of found your problem, with trim and up and running on plane you might have to much motor out of water. The cupped prop is keeping a bite even with it running in a surface piercing situation, the bad mpg is probably because of to much cup and your lugging your motor down. On my old promaster I ran a heavily cupped prop to help with my shallow water capability and and I raised my motor as high as i could on the transom (no Jackplate), but I lost rpm's and fuel mileage. Just my $.02 worth
 

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Roll Tide!
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15,787 Posts
If I'm picturing what you describe correctly, your prop and the cav plate are too high and/or too close to the transom. At 2" above the water line the cav plate isn't getting enough water pushed up to feed the prop. The step in the bottom of the transom will funnel water upward at speed, but there needs to be some distance between the back of the transom and the prop to be effective. The water doesn't come straight up, it comes up at an angle. The higher you run the prop, the more distance you need.

If I understand your situation right, a jack plate with about 4" of setback should solve the problem. If you don't want to invest in a hydraulic unit, get a manual one one play with it until you find the right height. The cav plate should be on top of the water, not in it when you are on plane (Sorry if you already know this, don't mean to be insulting)

Otherwise, I'd take off the Cav plate and find a way to lower the motor to get about 4 more inches of motor in the water.
 
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Discussion Starter · #11 ·
Thanks, I think I already knew what the problem was but, I'm sure my boat wasn't the only one that did this, and why should anyone have to run a jackplate on an unmodified boat to make it right. Guess I should be asking Bluewave that. Well I did but they said its a prop issue, and I do need to repitch. This will be my last Bluewave. I can lower the motor with a jp, right?
 

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Ankle Deep Custom Rods
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3,467 Posts
The Jackplate is going to mount into your existing engine mount holes, but then you could mount the motor lower on the jackplate to get your motor down. I would try a manual jackplate before you invest alot of money in a hydraulic one. I don't see it as a prop issue as much as a issue of the motor mounted to high on the transom or a short shaft, which either of these are a dealer issue not a blue wave issue.
 

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If your gonna run in the bays you might as well get the jackplate. Its the best thing I ever got for my boat. I can run much shallower now, and my boat is also faster, not as fast as yours. I have hit 51 mph on the best of days. I have a Blue 220 with at 150 Yamaha. I run a 19" power tech prop. My boat is lighter than yours but I have no problems. No tunnel.
 

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Flatfishr... sorry I didn't post any sooner. He meant that the propshaft is 1.5-2 inches below the bottom of his hull. That's where that particular prop liked to run. Different props seem to like different heights whether they are buried or barely piercing the water. I agree that you shouldn't have to buy a JP to make that rig run right, but sometimes the manufacturers don't realize what they are doing. Like I mentioned they told that guy that 60 would be the best he could ever get. A little tweeking and he's got that thing at 70.
 

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Roll Tide!
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15,787 Posts
Try calling Bauman's to get their thoughts on the prop. I've heard they are pretty good at solving these types of problems.
 
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Discussion Starter · #18 ·
Thanks Trim Change, Charlie seems pretty sharp, he did say that there was nothing wrong with the design, it has more to do with the operator. Charlie said that particular hull is a performance type hull, and performs differently than traditional hulls. Some venting is OK as long as its not causing dramatic speed loss. He thinks adding a JP and or removing some of the cup will get me where I want to be. I guess I'll try the JP first and go from there. Thanks for the help Ya'll. If you see a bald headed guy in a Pulse in the Gulf out of Sabine this weekend pull up and say Hi. Had a blast last weekend, big Kings, shark, spanish and one snap at a big weed line 15 miles out. Thanks again, I'll keep you posted on the progress.
 

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I'll bet it's the motor length. I had the opposite problem - 25" shaft on a 20" transom. The motor would overheat and then would slow down after about 5-10 minutes on plane. I finally found out when I was having a jackplate installed. Long story short - new motor was put on after I had owned the boat over 6 months and the problem went away.
 
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Discussion Starter · #20 ·
Would have been nice to work out a swap, but I think we have a handle on it now. Just need a JP and a littler prop work , thanks Ya'll and see you out there.
 
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