Prop Sizing Questions....

[thompsdw]

It appears as though I have spun my SS prop on my 18' Searay. I am now convinced that I should have a spare prop (duh, a little late now). My boat specs out for a 14.25x21 pitch prop.<br />I am looking at a 14.5x19 black max prop for a spare. I have plenty of room for the extra 1/4 inch, but the lowest pitch that I have seen speced on my boat with the big 4 cylinder is a 20. Will the 14.5x19 work fine on the ray? How sensitive are boats (caviation, etc.) to pitch and diameter? I am treading on new ground here...<br /><br />On another topic, anyone know of a good prop shop in Houston?

 

[sloopy]

Re: Prop Sizing Questions....

try to get your same prop in aluminum form! skips props in Pittsburgh is a great place.

 

[OBJ]

Re: Prop Sizing Questions....

Sloopy's right. Generally speaking, package boats come propped out for best overall performance. Dropping prop pitch, in your case down to 19 degrees, may put your engine on the red line for tach at WOT. Not a good thing. On the other hand, increasing pitch will slow the motor revs down and most likely speed. If memory serves, and sometimes it don't, general rule of thumb is for every degree added or subtracted from prop pitch, add or subtract 200rpms at WOT. I hope someone will correct me if I got that screwed up. Skips in Pittsburgh, as Sloopy said, may be able to fix ya' up with a spare aluminum prop. I deal with them and they are good people to work with.

 

[sloopy]

Re: Prop Sizing Questions....

Skip's is the best!

 

[sloopy]

Re: Prop Sizing Questions....

heres the phone number of Skip's<br />412-469-2160

 

[radsrh]

Re: Prop Sizing Questions....

OutboardJim you are correct each 1" of pitch will change the rpm by 150-200, if this is only going to be a spare prop what about one of the composite props out there it would save you a couple of bucks.

 

[Hooty]

Re: Prop Sizing Questions....

You could use the 19" as a spare, just be careful and don't over-rev.<br /><br />c/6<br /><br />Hooty

 

[Boatist]

Re: Prop Sizing Questions....

Txboatboy<br />OutboardJim is right on about the RPM gain. The 19 should GAIN about another 400 RPM's. So here is the question, with you 21 inch prop were you at the top of your rpm range for your motor?? <br />I have three props for my boat and I use two every year. I have a 19" and 17" Stainless Steel and a 17" aluminum. I keep the Aluminum in the boat with a spare nut, thrust washer and carter pin just in case. Both the Stainless steel props will put my motor in recomended rmp range. The 17 right at the top and the 19 about 400 rpms down but still in the recommended rpm range. When we go fishing in the ocean range and fuel mileage in important so I use the 19 pitch. Also my motor is tuned for sea level and makes a little more power there. In the river and lakes where starting and stopping is more important I use the 17. Many of my friends also change to a lower pitch prop for water skiing or pulling tubes with a full crew.<br />Fact that I change the prop offten also ensures prop shaft get greassed.<br />So if you know what your current WOT rpm range was you should be able to tell if the 19" will work for you. One last thing about my props, the highter pitch prop on my boat is faster ever though it is down about 400 rpms form the top of my rpm range.

 

[OBJ]

Re: Prop Sizing Questions....

Thanks to radsrh (whats that mean?) and boatist for keeping my gray cells in line. Rad has a point on the comp props. The are inexpensive when compared to metal props and give near the same performance metal props do. Least they will get ya' home if the main prop or parts there of go south. Taking for granted that we are all being pushed around by some big gas hog on the back of our floaters, I'd like to ask boatboy about his rig, mainly how his mixmaster is setting as compared to the keel. ie...where his vent plate is as compared to the keel. Are you running a jack plate?<br /><br />Boat - A definition - A fiber glass or aluminum hole in the water into which you throw money.

 

[Jim@KSC]

Re: Prop Sizing Questions....

Over the years I've spun 5 SS props and they all idled me back to the dock. Once it was 16 miles. <br /><br />Will a SS prop spin to where it won't even idle?<br /><br />The other comment I'd add is that you can effectively get a 20" pitch with a cupped 19".

 

[DocDan]

Re: Prop Sizing Questions....

Hello to everyone. I have been reading these forums for a few months and gaining a LOT of great information, but I have not registered before now.<br /><br />QUESTION/PROBLEM<br />I registered and am writing this since I guess I don't understand how this all works very well. These forums are obviously offered by the iboats.com company. They give us (I'm including myself) these tools FREE so that we can help eachother and get great information on all aspects of boating. Yet I asm guessing that they are in business to make money. So here's my question...why don't the users of these boards mention iboats more as a potential supplier? Take this board on props. SLOOPY .someone called an "Admiral"...then promotes some other prop site/company several times, even giving their phone number, with no mention that the site we are all on...iboats.com...also sells props. They seem to have a very good selection. So why no mention of this site? Don't they have good prices or products? Are we...and yes, I am including myself...cutting off the hand that is feeding us by not even mentioning them as a possible supplier? Or am I missing something? Does SLOOPY work for that other company? <br /><br />I for one would NOT like to see these boards go to a fee for use basis because we did not even consider supporting them with our boating purchases! Again, am I missing something? Why should we not at least throw a bone to these guys in the form of a good word to readers like me...and help them to keep this site up and free? What am I missing?

 

[DocDan]

Re: Prop Sizing Questions....

bump

 

[DocDan]

Re: Prop Sizing Questions....

Bump

 

[evin300]

Re: Prop Sizing Questions....

DocDan, I think you make a good point. However, if more people were to plug iboats, I am afraid that others would deem this message board as suspicious, and possibly question their motives.<br /><br />It's kind of a double-edged sword, if we all plug iboats then the site may seem advertisement driven, and there is plenty of that already on the net.<br /><br />I say, let the iboats business speak for itself, and keep the forum as free and open to differing opinions as possible, (that, IMHO is was makes it so good.) PS Welcome, DocDan!

 

[Forktail]

Re: Prop Sizing Questions....

"I for one would NOT like to see these boards go to a fee for use basis because we did not even consider supporting them with our boating purchases!"<br /><br /> Fee for use? Give us a break DocDan. Most of us are aware that iboats sells props, and obviously you are too. It is your poor asumption that "we did not even consider supporting them (iboats)". Of course we did. There is nothing wrong with a member passing on a good experience with another prop distributor. It's called word of mouth, and it has helped many here in the past. Any of these posts can be taken with a grain of salt, and we as human beings with a brain can make up our own minds on who we want to buy props from....whether we support iboats or some other place. I for one would go crazy trying to support the web sites I visit with my various purchases. <br /><br />"iboats retains the sole right to determine what will and will not be posted or transmitted on its sites. You are prohibited from posting or transmitting to or from this Site any unlawful, threatening, libelous, defamatory, obscene, scandalous, inflammatory, pornographic, or profane material, or any other material that could give rise to any civil or criminal liability under the law and you will be solely responsible and liable for those postings/transmissions."<br /><br />Sloppy doesn't work for the prop place, so I don't see anything wrong here Doc. Besides, the original poster asked for prop shop references. You've pulled the original topic way off base.

 

[OBJ]

Re: Prop Sizing Questions....

To Jim@KSC....I spun mine to the point where it just about wouldn't Idle out. And this was my old reliable 84' Johnny 50hp on my toon. And I was going with the river current. (yeah I know, big time boater like me with no spare, Duhhhhhhhh) I would guess if they are spun enough that the bushing is totally totaled they wouldn't work at all.<br /><br />To DocDan....I would have to surmise that the folks at "iboats" would know that sooner or later that some reference to the "competition" would sooner or later be thrown out in these forums. But if you take a good look at the posts, you will see that references to other companies is not the general rule. What I see is a bunch of folks that really care about boating and about the next guy out on the water. And it don't get no better than that. My hats off to the folks in the forums and to iboats for making it possible.<br /><br />Jim

 

[DocDan]

Re: Prop Sizing Questions....

Thanks to ForkTail and to OutboardJim for their replies. I agree that from what I have read so far the people on these boards seem to be genuine in their efforts to help others. And that kind of helping others without looking for gain, in today's world, is rare indeed! Thanks to all those who help the rest of us, even with suggestions of competitors. I guess I just don't want this golden goose to get killed. I hope to be able to add to the good information when there is something I know about, and if I find a good deal I'll buy it from these folks. Happy new year to all.