What is the topspeed from a lund explore 1725 with a optimax 115

[LUNDJE]

What is the topspeed from a lund explore 1725 with a optimax 115

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Hey, I have a lund 1725 expolre with a Mercury 115 optimax, what prop do I need? Lund specification says that I need a pitch 16, this is way to small, and get about 6000 rpm I have a prop youse 19 engine to 6000 rpm when I trimt is out for 100%
I treyed a prop 21 the boat go's to 42.5 miles top speed with a 5150 rpm 100% trimt out
Yesterday I treyed a prop pitch 20 the boat go 44 miles top speed with a 5600 rpm 100% trimt. Can you tell me what is the best prop for my boat. Do you know what top speed I can aspect from this combination boat/engine. The original owner told me that this combination go's 50 miles top speed. Pleasse response r.smeets@telenet Belgium sincerely Thanks Robbie
The speed is from my gps so I think this speed is correct information

I do not know whether this is the right path to this is the first time in this forum and sorry for my Englis we speak Flamisch

Robbie

 

[sschefer]

Re: What is the topspeed from a lund explore 1725 with a optimax 115

Robbie, the prior owner was not fooling you. He probably read 50mph with a 19 or 20 pitch prop on a regular spedometer. They tend to read 5 or more mph higher than the more accurate GPS speedometers.

Your motor should run steady around 5800 rpm with a 19p 3 blade prop at sea level and that's right where you want it. Drop an inch in pitch for every 2500 feet of altitude. With that setup, your boat should see 43-45mph on the GPS..

Different prop styles can add different results but on that boat, stick with a good general purpose stainless steel prop like the Quicksilver Silverado (Formerly Vengance) and you'll have the best all around results.

 

[LUNDJE]

Re: What is the topspeed from a lund explore 1725 with a optimax 115

Thanks Sschefer,

That is the correct information I need, know on the moment I have a pitch 20 a quiksilver laser 2.
If I can find this prop in a 19pitch, wil bring me that to a perfect speed? Becausse I already tryend a 19 pitch it was a stanless steel solas it brings me to a speed on gps about 42.5 mph white 6000 rmp(isn't that to mutch)can make an other prop the differance?
What is the best prop on the market, do you know the fury(mercury prop, Kevin van Dam has one on his boat and I read some revieuws about)

But the 16 pitch vangence prop origenal on that boat is mutch to small, this was what Lund recoment for this boat!

Look out to your replay, and your advice.

Sorry for my bad English

Kindest regards
Robbie

 

[sschefer]

Re: What is the topspeed from a lund explore 1725 with a optimax 115

Robbie, if a 20 Laser has your RPM at 5800 then that's what I would run on it.

Van Dam is running a different hull style than you and he's also got a sponsor paying him to say nice things. If there's one thing that will eat your money up faster than anything it's chasing props. I've come to the conclusion that chasing a couple of miles per hour is just not worth it unless you're getting paid to go faster than the other guy.

 

[LUNDJE]

Re: What is the topspeed from a lund explore 1725 with a optimax 115

Dear sschefer, thanks for your positif advise, how comes you kwow so mutch abouts setting a prop?
Dou you have also a Lund are do you have the expertise from Mercury?
This forum is New for me, and I trey to figure out what every one use on the wather.
Is it inportend how high the motor is hanging, I think the motor is 1 inch higher about the bottom off the boat.

The laser is it a good prop? What is the differece between the mutch more expencife prop from vangence?

Look out to you response
Robbie

 

[sschefer]

Re: What is the topspeed from a lund explore 1725 with a optimax 115

Robbie, I have a 18' Fish/Ski simmilar in style to your Lund. Mines heavily loaded with three big batteries and the 20 gal gas tank. With my 200+ lbs and my buddies 250+ lbs, I manage a comfortable WOT 44.9 mph.

I'm running a 135 on mine with a 17p Mercury/Quicksilver Silverado general purpose prop. Merc replaced the Vengance model with the Silverado model but they are pretty close to the same. I have my engine timing set low and she runs cool and sweet but probably isn't producing more than 115hp.

My max RPM is 5200 RPM and I hit it right on the nose. Your inline 4 is rated at 5800 RPM and that's the number you should shoot for. 2 stroke motors don't like to run under a load and the way to prevent that is at the prop.

I'm just a hobby boat and engine builder and I've learned a lot from folks on here and I have a number of other resources that I study. I currently have a project motor going on called the 2010 Frankenmerc project. FrankenMerc is a term used for a motor that comes from parts of several different motors. A fun project for sure but it's killing my bank account. I don't recommend anyone try it that doesn't want to do it just for fun.

Ill post a link to the thread but you have to promise not to try this at home..

http://forums.iboats.com/showthread.php?t=369265

 

[LUNDJE]

Re: What is the topspeed from a lund explore 1725 with a optimax 115

Hey sschefer,

I look to the link you send me, pffff that is serieus work what you are doing!!!!
Now I understand than engins/motors dont have anny cind of secreds for you.

Sschefer How can i put a picture on this topic?
Do you have pictures from your boat?

Sschefer, what dou you meen with(Your inline 4 is rated at 5800 RPM and that's the number you should shoot for. 2 stroke motors don't like to run under a load and the way to prevent that is at the prop) is it better run at 5800 than running on 5400rpm( is it better for the motor are does is give better results?



Kindest regards

 

[LUNDJE]

Re: What is the topspeed from a lund explore 1725 with a optimax 115