Not as fast as I thougt it would be!

[equium]

So I rescued my father in law's boat from rotting away in his garage for the last 15 years. 1975 Galaxie tri-hull with a 165 I-6 Mercruiser I/O. My friend (a mechanic) got the engine and outdrive tuned up. We took it for it's maiden voyage in almost 15 years. According to my GPS, our top speed WOT was about 33 MPH. I'l admit; I'm used to faster boats. My friend checked the carb and verified that it was indeed WOT and couldn't adjust it any further. Is a PROP change my only option? I am not ungrateful, seeing as how he pretty much gave us the boat. (my wife learned to ski behind this old timer). I would just like to get a few more MPH out of her to keep up with others.
Thanks for reading.
danny

 

[bhammer]

Re: Not as fast as I thougt it would be!

Before we can help, we need to now what WOT RPM was for this run. Also, what kind and size of prop do you have. What is the WOT rating of the engine? I am sure someone will know this, but I don't. It's usually on the engine or in your owners manual.

 

[Joe Dirt]

Re: Not as fast as I thougt it would be!

That doesn't seem out of line at all for an older tri-hull with an average sized motor. Run it for the fun and novelty, not the speed. Pics? I love the old tri-hulls.

 

[RyanSS]

Re: Not as fast as I thougt it would be!

I've got a 15 ft 1981 Cajun tri-hull w/50 hp mercury and it will run 32 mph according to both the speedo and GPS.

 

[45Auto]

Re: Not as fast as I thougt it would be!

I think mid to low 30's on a 6 cylinder 38 year old tri-hull is about all you're going to see. My 15' 1980 tri-hull with a 4 cylinder will just break 30 MPH on the speedo (don't want to know what real GPS would be !

Sell it and get something else before you waste any money on it if you're looking for more speed. Otherwise, as Joe Dirt says, run it for the fun of it! Make the others slow down to your cruise speed!

 

[NSBCraig]

Re: Not as fast as I thougt it would be!

Yeah your probably doing the best you will with that package.

I don't no about where you live but most of the waters around here are only 30 mph zones.

 

[equium]

Re: Not as fast as I thougt it would be!

Thanks for the replies. Seems like 34 MPH is about right. I'm not getting rid of the boat because of the sentimentle value. I can live with it. I recall my father in law had two or three props in his garage when I rescued the boat. According to my wife, he used to change props several times during their camping trips (back when she was younger). I'm going to call him and have him save those props for me.
There might be a prop that will get met to 35 MPH.
Like Joe Dirt said, I'm going to run it for the fun of it. heck, it was free.
Thanks again.

 

[xxxflhrci]

Re: Not as fast as I thougt it would be!

The motor could be getting tired, the prob could be the wrong size for speed. Who knows? However, I would think that it would do a few mph more if everything is "right". My 140hp 17.5 ft Galaxy v-hull will do 40-42. By comparison, there is super nice 140hp tri-hull on our lake that I see about every trip out. It easily passes me and walks away at WOT.