wot

quote:
Originally posted by krb260

I useually trim tho outdrive all the way in and use the tabs to the point where handling is compromised

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Does anyone else besides me think that trying to run at wot with the drive in and the tabs down is crazy and probably why his boat doesn't go fast. You are pushing the bow into the water, increasing wetted surface area and adding a whole lot of drag. I bet it handles real lousy too. I tried that once on a 24' SR and was amazed at the size of the bow wake and how quickly a slight movement at the helm became a quick turn.

For wot, get the boat on plane, make sure the tabs are up, and then start trimming out the motor. With my current 23' cuddy, I can usually pick up a couple knots and 50 rpm just by trimming out the drive at cruising speed.
 
I agree with both Scott and zeezer. I know when I was having difficulties with mine, I was trimming and playing with trim tabs etc. all of which helped but still not right. As for zeezer's comments, he is absolutely right about jumping all over the dealer. My boat was previously owned and I had a harder fight because the dealer claimed the previous owner never complained about it. The boat only had 50 hours on it and had been used for the most part in a "no wake" river by a "new to boating" owner. I ended up agreeing to pay a small amount to have my gear ratio changed. Sometimes new doesn't mean it's perfect!
 
Wot with drive trimmed in and tabs full down...bad form, really bad form. [:-paperbag]
 
Drive trimmed down and tabs full down is like pulling an eight furrow plow.......not much fun and very expensive.
 
quote:
Originally posted by PascalG

"top speed is 28-30mph depending on tide at 4600 wot planing speed is 22mph and the prop shop recomended against taking pitch out and said to try them again and get back to them"

something isnt' right here... you should get well over 30kts top speed with a sterndrive 26 footer. it should also stay on plane as low as 15/16kts. are those speeds GPS ?

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And how does tied effect speed unless you're dragging on the bottom!
 
"And how does tied effect speed unless you're dragging on the bottom!"

If you are measuring speed using a gps and you are going out with the tide, your speed will be faster by whatever speed the tide is moving. Doing 20 knots with a 2 knot tide, the gps will read 22 moving with the tide and 18 against it.
 
Good advice above regarding complaining to the manufacturer. I know of at least one instance
where Sea Ray/Merc paid for a gear change. Have the dealer take a spin with you to confirm
you are doing the right things with trim and tabs. Have them confirm it with the mfg.
 
I have the same 2004 350mag mpi b3, 2.20:1, 20" cupped props setup on my 26' Crownline. Requires 24-25 mph to maintain plane at 3500 rpm. WOT is 4900rpm/39mph, when the drive and props are clean. This may sound crazy but it is super sensitive to barnacle growth on the drive and props. I usually lose 5-7 mph every month or so until I clean it off and the performance is restored. The crazy part is that it doesn't happen with the 22"uncupped props.
 
krb,

According to my notes, my props are the 20P uncupped, 2.20:1 ratio on the outdrive.
 
For the record I want all of you to know that I am a good friend of krb260. On friday we splashed his boat for a sea trial with an authorized Merc Rep. Hopefully I can give all of you another perspective without stepping on my buddys toes. As you might know his props were sent to a shop for analysis. Props were in spec but slightly out of balance. The shop balanced and "cleaned" them. Thats it nothing else. The only other variable that was different was the fact that there was no barnacle growth on the outdrive and trim tabs. Boat was cleaned very nicley last fall. I know this because I was the one who did the scraping. With the boat clean it ran at 4950rpm off his tach and the merc reps computer. We checked this at least three different times. All with the same results. The merc rep said the engine was running perfectly. During the acceleration test I felt the boat performed nicely. It jumped onto plane and had a max speed of 31 knots off gps. Keep in mind this was going upriver with the tide going out. You might want to add three or four knots for the relatively strong current in that area.

If this were my boat I would attribute the wot issue with barnacle growth. What concerned me the most was the way in which the boat needed to be operated in a safe manner. When the merc rep was slowing from wot to 3200rpm or wot to 3500rpm the boat had a very bow high attitude! Keep in mind that there were three very experienced boaters using trim and tabs to correct this issue. What we found was that the boat needed to be run at about 3800 to 4000rpm to run correctly at the stated load. Other conditions that might be worth noting outside air temp was 52 degrees very low humidity water was dead calm. With the summer heat and high humidity coupled with two to three footers this boat in my opinion would not be fun at all to operate.

The question that I would like to pose to all you experienced boaters on this forum is at what percentage of WOT should you be able to comfortably cruise at? I think 77 to 81 percent is to high (3800 to 4000/4950wot). What kind of engine life can he expect with those numbers? My boat a 2004 340 Sundancer runs great at 3200rpms (69%). I know it has twins but at least I am not burning up my engines to maintian a nice plane.

I hope that this post answers some of the questions that many of you might be thinking. Any further advice or opinions would be greatly appreciated.
 
quote:
Originally posted by ras737

The question that I would like to pose to all you experienced boaters on this forum is at what percentage of WOT should you be able to comfortably cruise at?

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An old-school, rule-of-thumb... 75%.. though I may have to qualify since I notice you mentioned "comfortably". 75% is usually associated with "max" cruise.
 
quote:
Originally posted by Ted C.

I have the same 2004 350mag mpi b3, 2.20:1, 20" cupped props setup on my 26' Crownline. Requires 24-25 mph to maintain plane at 3500 rpm. WOT is 4900rpm/39mph, when the drive and props are clean. This may sound crazy but it is super sensitive to barnacle growth on the drive and props. I usually lose 5-7 mph every month or so until I clean it off and the performance is restored. The crazy part is that it doesn't happen with the 22"uncupped props.

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ted c thanks and are you telling me that the 22 uncupped props work well for you. Nobody has mentioned this option. kraig
 
On my boat the 22" uncupped is only about 1 mph faster at the same rpm as 20" cupped. Both require 24-25 mph to maintain plane.
 
Boat should be doing much better than reported. Please see my last couple posts in the SRO forum.
 
I have a 1985 26' SeaRay with a single 260 HP I/O. I have to get to around 19 MPH to get on a plane, cruise at about 21 MPH at 3200 RPM. Top end is a disappointing 27 MPH.

The original prop was a 15.25 x 15 though, and I couldn't get over 3600. The first prop guy said the same thing your guy said - according to the book, it's the right prop. The second prop guy had me try a 16 x 14 prop. Now I get up to 4300, although the top end hasn't changed much.
 
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