18ft dixie pushed by 115 evinrude

[Carpenter2486]

hello everyone, i have an 18ft dixie boat, somthing like a bassboat type hull, and powering it is a 1981 115 evinrude, motor seems to run perfictly fine, i am wondering,, at wot it only hits 39mph, trim up and glass water, only myself in the boat 170 pounds, im wondering if that is normal speed for that boat, or if i have to look into water logged foam and whatnot.. im curious about this becuase my father has a 90hp evinrude on a 19ft boat and he is slightly faster than me.. just wondering what you experts thing of this situation...

 

[Part-time]

Re: 18ft dixie pushed by 115 evinrude

First off, is that GPS speed or the boats speedometer?
What pitch prop are you running?
The only way to tell is take your WOT RPM's, GPS speed, prop pitch and the gear ratio in your lower and input here.
If your slip is under 15% you're ok, but below 10% is really where you want it to be.

Also... what year is your father's motor? Your '81 will be crank rated, if his is newer it will be prop rated, a good 15% difference.
Basically, your 115 would become a 90hp when rated at the prop.

 

[Bob_VT]

Re: 18ft dixie pushed by 115 evinrude

Yes you are running at speed maybe a MPH slow but fine.

 

[Carpenter2486]

Re: 18ft dixie pushed by 115 evinrude

my father's motor is the same year as mine, if bob is correct and my boat motor combination is just abit slow,, how can i gather abit more speed,, its just abit discouriging when a bigger boat with smaller engine is going faster than your sleeker boat with bigger engine,, the prop is a 17 pitch.. his aswell is a 17 pitch.. what would be something good to switch too.. im asking because im completly unsure..
:facepalm:

 

[Chris1956]

Re: 18ft dixie pushed by 115 evinrude

Well, do you have a way to get a max RPM reading out of the motor? You might (might) be underpropped. Of course, if the prop is on poor condition, that could cause a bit of speed loss. Without going to a larger engine, you are not going to change your speed very much. Likely a few MPH, if you can find the best prop and trim combination. Are you trimming the motor? If you don't have power trim, you could move the tilt pin out one hole and see if that helps or hurts top speed.

 

[Bob_VT]

Re: 18ft dixie pushed by 115 evinrude

Considering the boat is a 1981.......the flotation could be water logged and the extra weight is horrible on performance.

 

[steelespike]

Re: 18ft dixie pushed by 115 evinrude

We need your wot rpm and speed.How is the hole shot in seconds.Does your boat respond to up trim?
Is your antiventplate (just above the prop) even with or slightly above the bottom of the transom.Does the boat have a
pad?Is it a glass boat?Is your throttle opening all the way?It would seem that a 17" prop is a little light but can't tell without a tach.

 

[Carpenter2486]

Re: 18ft dixie pushed by 115 evinrude

the boat dosenot have a tach,, unfortionatly.. but the holeshot is not to bad, from dead stop maybe 5- 8 seconds to get up to plane. and yes, trim gives me aprox 3 mph faster. my prop is brand new, maybe a season on it with not a ding, i just ordered the exact replacment for the one that was on it... and the antiventplate is just above the bottom of the boat...

 

[Texasmark]

Re: 18ft dixie pushed by 115 evinrude

I don't know the hull shape of that boat, nor that of your fathers. I had an 85 engine rated Merc on a 16' pretty flat transom area and 39 was tops. Had a 125 Johnny, also engine rated, on an 18' heavy tri hull with a fairly good dead rise and 39 was tops for it, but I had a reduced pitch prop for water skiing. I was running either a 17 or 19 SST prop; don't remember. If I wasn't skiing I could have come up to the next pitch and coaxed a couple more mph out of it.

The shape of the hull will make a difference. Your plane out time sounds like you are pretty well matched to your prop. If pitch was too low hole shot would be really fast, too high, really long; again hull shape makes a big difference.

As the other guys said, numbers would help and so would a picture of the transom area of the hull.

My 2c,

Mark

 

[emoney]

Re: 18ft dixie pushed by 115 evinrude

Just curious, but have you been "side-by-side" with your Father-in-law and watched him literally pull away from you? If not, and don't let this shock you, but folks have been known to "over exaggerate" their top speeds when it comes to boats. As a matter of fact, it's safe to assume EVERY boat owner has (some still do) fudged their numbers. Not sure why, it just comes with the territory.

However, even if you've seen it, you've got to know that you're not comparing apples to apples. Back in 1981 manufacturer's didn't have the same requirements as they do now when it comes to horse power rating. Some were known to, again, "exaggerate" or fudge a little where it's measured. I'd never compare my boat's motor to someone else's that has a different make/model all together. It's not the same and they're not the same. You can probably take comfort in the fact that yours shifts into gear a lot smoother than his does, so you've got that going for you, lol.

 

[crb478]

Re: 18ft dixie pushed by 115 evinrude

You are about at the speed you should be. Dixie boats were generally built on the heavy side which will slow you down a little. You really should add a tach to maximize your set up. I would tach that motor at 5500-5800 rpm since they seem to like rpm then you can get the best prop and motor heigth.

 

[Carpenter2486]

Re: 18ft dixie pushed by 115 evinrude

i think i see where im stood still here, this weekend i will install a tach on the boat, just so we can get to the bottom of this.. also "" emoney """ i was direct beside my father on the lake when we were both full pin.. i will also get a photo of both my hull and fathers just to compare.. il repost in a few days when i have all the new info and photo;s Thanks alot guys

 

[Rebait]

Re: 18ft dixie pushed by 115 evinrude

I am new to the forum but not to boating or owning a Dixie. I bought my 1980 185 Center Console new, February, 1980 at a boat show. It was originally powered by a 115 Horse Merc. I replaced the 115 with a 125 Merc in 2003. This boats runs a lot faster than 39, no exageration. ( I agree with you on that emoney) I have a 13 x 19P Aluminum Prop. (in case I hit something) I will attach a picture to see if your hull is the same. I remember their bass boats had a hull almost like mine.

 

[jigngrub]

Re: 18ft dixie pushed by 115 evinrude

I get 32 mph in my 17' tinny with a 50 hp 4 stroke.

It never hurts to check your boat for waterlogged foam and rot, as a matter of fact it is a very good thing to do.

 

[Solittle]

Re: 18ft dixie pushed by 115 evinrude

I take it that your goal is to beat dad. Easy - swap out your 115 with a 140 keeping the cowl of the 115. He will be busting his chops when you walk away from him in your "115".

 

[Frank Acampora]

Re: 18ft dixie pushed by 115 evinrude

If you want more speed, you would be better to go to the OMC forum. The 4 cylinder engines may have used different lower unit gear ratios for different horsepower ratings and you may be able to swap one in. Then a re-prop will give more speed. Switching to a stainless prop of the same pitch will usually yeild200 RPM and 1-2 MPH more. This is because the stainless has less parasitic drag so more horsepower goes into driving the boat rather than spinning the prop.

Some people swear at aftermarket reeds, some swear by them.

Comparing your two boats is like comparing apples and orages. There are so many variables that it becomes impossible to say why yours is slower than your dad's.

 

[Carpenter2486]

Re: 18ft dixie pushed by 115 evinrude

i opened up my floor, i found 500 pounds of soaked fotting foam and plywood, after that dirty job i re plywooded it with marine grade and re foamed it closed cell, i took it on the lake this weekend and on GPS i hit 46MPH just myself in the boat, i was quite amazed, i beleve il invest in a 13.19 prop, and i will have more updates from their! rebait my under hull is the same, but my side walls are abit differnt, yours go straight up it apperes. mine make the boat wider, their on more of an angle.. but they are simular.

 

[Rebait]

Re: 18ft dixie pushed by 115 evinrude

Carpenter, when I read 39 mph, I thought no way! Look for speeds in excess of 50. When I first got the boat I could not believe the speed and performance, for I went from a 25' wooden Eastern Sea Skiff. I redistributed my weight through the years to get the weight off the transom. In 2003, when I had the new engine installed, the dealer checked the transom and could not believe that there was no rot. He could not believe the overall condition. He told me that he never had a center console jump up on plane so fast and perform the way it did. I had the same competition with my dad until he died in 1998. Good Luck.

 

[Solittle]

Re: 18ft dixie pushed by 115 evinrude

i opened up my floor, i found 500 pounds of soaked fotting foam and plywood, after that dirty job i re plywooded it with marine grade and re foamed it closed cell, i took it on the lake this weekend and on GPS i hit 46MPH just myself in the boat, i was quite amazed, i beleve il invest in a 13.19 prop, and i will have more updates from their! rebait my under hull is the same, but my side walls are abit differnt, yours go straight up it apperes. mine make the boat wider, their on more of an angle.. but they are simular.

On the 13.9 prop - You need to check your rpm''s at WOT and see how this compares to the max recommended by OMC. My guess is the max recommended rpm for your engine is around 5,500 rpm. A 13.9 may get you quite a bit over that. I suspect a 15" will get you max performance.

 

[kawakx125]

Re: 18ft dixie pushed by 115 evinrude

On the 13.9 prop - You need to check your rpm''s at WOT and see how this compares to the max recommended by OMC. My guess is the max recommended rpm for your engine is around 5,500 rpm. A 13.9 may get you quite a bit over that. I suspect a 15" will get you max performance.

he originally posted 13.19 prop, i'm assuming he probably meant 13x19 given he thinks his prop is a 17p currently