PROP SIZE

[1bigdog1]

I have asked this question here before and got very different answers.. Some recomended a 19 pitch and others all the way up to 26....<br />The boat is a V-hull 19' with an old 78 Evinrude 235. It does not have a prop on it at this time and I want to know what size would be good to start out with. Im mainly concerned with fuel economy and a nice top end. I wont be pulling up a lot of heavy skiers but will pull a tube on occasion.<br />Please give me your thoughts. I have looked at all the sites that people in here have recommended but Im still pretty much at a loss.<br />Thanks,

 

[ob]

Re: PROP SIZE

According to the OMC propeller guide and not knowing the exact weight of boat and gear it looks like a 14 1/4 X 21 is a good starting point.Is that the motor that fell off of the truck?

 

[1bigdog1]

Re: PROP SIZE

Thanks, I appreciate your answer. Will be doing a test run soon I hope.

 

[ob1jeeper]

Re: PROP SIZE

Some suggestions: But in almost ALL cases, you will need to be able to provide weight, hull design, etc. OR... be able to provide the boat for inspection, or minimally photos of it, so they can assist you...<br /><br />1- Hopefully you have a dealer in the area, who originally sold this boat combo, and or something similar. Ask thier advice on a prop for that combo.<br /><br />2- Also, many of the larger towns, have shops that specialize in props and prop re-builds, who would be a good source of advice.<br /><br />3- There are several web sites, who can help you, as they have prop selection guides. (MICHIGAN WHEEL, is one that has a GOOD guide to prop selection)<br /><br />Last, but NOT least, you should be aware, that if you intend to operate on water of differing elevations, (like a lake at 4000 ft elevation, and at sea level) you most likely will need a different prop to accomdate the differences in available power, due to different air densities.<br /><br />Good Luck, Obiwan Jeeper

 

[1bigdog1]

Re: PROP SIZE

<br />OK theres a pic of the boat,

 

[1bigdog1]

Re: PROP SIZE

or better yet here is a link<br /> http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=2400483338

 

[ob]

Re: PROP SIZE

1bigdog1,The boat pictured is a 1983 18 ft del magic walk thru windshield.I'm guessing the top rated hp for a rig like that to be in the 120 hp range.235 is way too much motor for that boat.Considering he's willing to give the boat away along with the trailer raises questions as to the structural integrity of hull ie the transom.Don't know whether you have other motor options at this time however I am going to recommend against hanging a 235 on the back of that rig.

 

[ob1jeeper]

Re: PROP SIZE

The guy you are purchasing the hull from (Chuck) has been around boating for "a while", and I am sure that he can provide a pretty good estimate of what would be a good prop to start with, if you tell him what motor you bought, and what elevation waters you intend to operate on.<br /><br />I had an almost identical hull until a few years ago, which I used for fishing & "family boating". It was powered by a 140 HP which needed a 14x19 (inches dia x inches pitch) from sea level -up to- 2500 ft elevation, and a 14x17 from 2500 -up to- 5000 ft elev.<br /><br />Just realized (re-read your post on motor size...) I agree with ob regarding the motor. That's a LOT of motor to be hangin on this hull.<br /><br />However, if you INSIST on using that big a motor, my guess is that a 3-blade prop in the 15x23 range would be a respectable place to start. you MAY be able to get by with more pitch, if the motor has good compresion, etc. or need less pitch if it's a tad tired, or you go to higher elevations.<br /><br />in either event with this 235, I can relate to you from personal experience (BAD experience) You DO NOT want to be turning too slow (under 4700 at WOT), nor too hi an rpm (over 5200 @ WOT) on this motor, or else you will be buying a rebuild "P.D.Q.", as it has a tendency to break rings when turned too hard.<br /><br />But if I were in your shoes, I'd be asking Chuck, about motors AND props. I'm confident he'll steer you in the right direction for a starter motor and prop, and may even be willing to trade in or exchange your 235, for something a tad more suited to the hull.<br /><br />I also believe he would give you some pretty good advise on maint, fuels & oils, etc to keep from "shaking the rings" out of whatever motor you end up with...<br /><br />Good Luck, Obiwan Jeeper

 

[1bigdog1]

Re: PROP SIZE

LOL, so you know Chuck also, good guy he is. He recently described a blowup to me as looking like it was grenaded, lol. He is the one puting the motor on for me and Im sticking very close to what he recomended for the prop, just seeing what others had to say. Im glad to hear Chuck is well known as he has done me very well and would recommend him to anybody.<br />Thanks for your reply

 

[ob1jeeper]

Re: PROP SIZE

While I still think that's a lot of motor for this hull, Chuck has WAY more experience with boat & motor set ups than I, so I'm going to defer to him on this one...<br /><br />Good Luck, Obiwan Jeeper