scottgjerdingen

When I picked up my 32 AT the props had been stolen and I had no reference points on what should go on the boat. Back then I had posted here for recommendations and came up light...that is probably to be expected, I guess there are not a lot of 32 AT and I thing only 170 or so HP 450 were build (if the range of serial numbers for the engine is an indicator of how many were produced). I put my prop guy in the awkward position of putting in a prop order for a boat I had owned 2 days and had yet to even put it in the water. I told him I was thinking/guessing 4 blade ss 25p, but I was more interested in a getting a set of loaner props to get the boat on the water than I was in discussing the intricacies of options. 1 month later and with a manufacture backlog I mentioned 24p's would work if we could get them faster. About 3 weeks later my props finally arrived and I picked them up tonight. Until tonight I did not know what was ordered so it was kinda exciting to see what arrived. What I ended up getting was a set of Powertech OFX4's, 24p


[ATTACH=CONFIG]558959[/ATTACH]

If for some reason the link doesn't work, here is how powertech describes the prop - 15.25" DIAMETER, AVAILABLE IN 15"-28" IN PITCH, 4 BLADES, RIGHT- AND LEFT-HAND ROTATION, MODERATELY HIGH RAKE, HIGH ASPECT RATIO X-CUT GEOMETRY, AGGRESSIVE CUPPING FOR EXCELLENT LIFT AND GRIP CHARACTERISTICS, BETTER MOTOR ELEVATION CAPABILITY THAN OFX3, USED ON MANY HIGH PERFORMANCE FLATS, ESPECIALLY WHERE GRIP IS AT A PREMIUM - POLISHED FINISH ONLY

Side note - What does HIGH ASPECT RATIO X-CUT GEOMETRY mean? Should there be a comma between high aspect ratio and x-cut geometry, if so, then what is x-cut geometry? Also, what does "better motor elevation capability" imply? if this possibly an improper use of motor s engine? and if so, is it saying it helps the engine ride higher? and if so, does that tend to contradict the moderately high rake statement which I dumbed down to mean it will make the boat will want to plant it's ass and put it's nose way up in the air? Obviously some over thinking going on here on my part, and on top of that it is probably all wrong. Anyways, back to my story

The AT has twin HP 450's and I had asked for 25p's thinking that was enough hp to spin them, but a match set of 25's apparently either would have taken longer to arrive or my prop guy jumped on the opportunity to downsize a bit when I offered that as a concession to get the props faster. These go on tomorrow and i'll see where I stand...

I've never run a 4 blade prop before using the 21p loaners which looked like nice props, but they went on the boat so fast I couldn't even tell you what they were beyond 21p, 4 blade they were shiny going on (SS), and green coming off. To date I have not pushed the boat and I wasn't all that interested in doing this with loaner 21's. My only speed/rpm based reference I have gathered to date was an incidental observation where I found myself doing a touch under 50 @ a bit under 3500 rpm in a typically (over) loaded rig that was about the complete opposite of trimmed out.

Tomorrow i'll have to crank this up a wee bit.

What's the word on these props; brand, model & pitch? Do you think we chose a reasonable starting point? Any thoughts of the pairing of these props to the boat and the hp 450's? Any positive or negative behaviors I might want to be aware of? If doing a bit under 50 @ a bit under 3500 rpm with the loaner 21's, where do you think these Powertech's will put me under similar 3500 rpm circumstances? BTW - any insight into a redline/max rpm on the hp 450's? I am guessing 5-5,200 rpm?...i'm not going to push the boat any harder than this on the high end or even attempt to come out of the hole hard until I get some work done to it (and boy does this take extreme patience!), but where do you think this would put me at a top end speed? and also at coming up on plane?

Anticipating it matters for my top end question, I looked up the bravo gearing info a couple months ago and if I remember correctly I have the middle of 3 1996 bravo options (if this makes sense), would something like 1.50 make sense here...it seemed to be meaningful to my prop guy?

One last question. The manufacture tag in the pic references 135 to 350hp. How should this guidance be used? I can't imagine 135 hp being a low hp reference...is that enough to even spin these props properly? is 350hp some form of high water mark where more hp will cause to slip wildly?...or maybe this is just some form of cya/legalize?

Thanks in advance for your feedback!

- scott -

Griff

Where did you ask about props for a 32 AT????
Those are going to be way too small if you have 1.5 ratio drives which is 99% most likely the case. Chances are they have rubber hubs and thus the 350hp rating.

Stock props would have probably been 28" Bravo 1 4 blades. Most HP500 32's run 30" Bravo 1's.

With 502mpi's and 1.36 ratio drives, I spin 24" Bravo 1's at around 5100 rpms. If I had 1.5's I would need something around a 27" Bravo 1.

The HP450 rev limiter should be around 5350-5400 rpms.

scottgjerdingen

Hi Griff - now that you have me thinking a bit more about where I posed questions for a prop recommendation, I actually did not post the question, I had PM'd a couple people here I had been talking to and getting feedback on the boat before I bought it (heck, at that time I don't even think I was aware of this AT forum....and your insights. Where is the emoji of a guy kicking himself in the ass when I need it :-)

So, now that my bubble has been burst, here comes the back peddling :-), given top end speed is not yet my #1 goal here and I knew these would be a starting point in nailing the right props (I just didn't think I would be so far off)...is there any benefit at all to running these props besides serving as a prop to move my boat in the water over the end of summer holiday weekend and for the remainder of the season? (I have returned my loaners so w/o these I am propless). I think I just answered my own question & it sounds like I will be running these until I can pick something else up (but i will make a quick call to see if I have some exchange options).

SO, having just learned a $1+k lesson I don't wish to repeat, it seems reasonable that 28" Bravo 1 4 blades would be the OEM option, are there other options that should be considered ahead of these? Or, as I mentioned, with top speed not being a goal (heck the lake I have this docked at even has a 45 mph speed limit which is enforced), should I not even bother doing anything yet this year and so some research and bargain hunting during the offseason? OR, Now here is a rationalization, is there any chance I could argue the 28" bravos (or other suitable recommendation) would give me better gas economy over distance traveled? Might the cost of a used set of 28's be offset in savings on my $600 a week gas bill? Like I said, its a rationalization, the $600 only gets me 120gal @ lake prices, so it would probably take quite a few tanks even if this were possible.

Lesson 2 - yea, it is a rant. It sure seems difficult to get good local advise. Especially for a state boasting 10,000 lakes. Last fall I wanted to change up the drive on my old Monza and I was advised to replace the vp 280 drive with a duoprop would be pretty easy. Over the winter I acquire the drive, spent another chunk of dough on a prop for that and now the shop that advised this and was to install this the duoprop and who has had that boat since march comes to me and tells me it isn't going to be an easy install because they need to cut a bigger hole in the transom to fit this and when that is done it will be pretty close to the exhaust so they are thinking the transom needs to be somehow re-enforced and the exhaust should be moved. Now this has been deemed a "winter project" because soon they'll be pulling the boats out of the water & doing minor summertime fixes to other boats is more lucrative. And the estimate to do the work has increased by somewhere between 3 & 5x (with final determination to be done later) SO, now I am confronted with scrapping the project, having a drive I can't use, and paying to put the boat back together the way it was, or realizing this project is probably going to cost me about the value of the boat and there would be no chance of recouping this if i were to sell it. Furthermore, if I keep it the way it is, I'll continue to bust shear pins (at best) or twisting the drive gears (both of which have been done a couple times ..argh & apologizes for the off topic rant. Heck, while on a roll, one last statement. It sure seems that in general, over the last 5 or so years, many areas in service industry (not just boat related, this is a broad statement) are proving incompetent and it has become difficult and/or a crap shoot locating competency. Example, I need transom work done on the AT, should I really have to ship the boat a quarter of the country away to someone like glassdave to get the job done properly? Could be i'm not doing my homework, but there was a time this homework really wasn't required. If someone said they could do a job, they actually could do it properly, on time and on budget - it was a pride thing. Now it appears the process is; a) get the job even if confidence in doing it right is uncertain, b) simply do it for the $. I guess I am dating myself. END of rant :-)

VoodooRob

As Griff stated you need to know what drives you have. Most likely 1.50s and your new props are way small.

scottgjerdingen

the drives are 1.5, I am certain of this.

I sent the vendor who made this recommendation and sold me the props an email making them aware of this feedback and a few other things. I also will be calling them today.

When I purchase these I did inform them that this was a 1.5 with HP 450's. I get the vendor is probably not as knowledgeable of the boat than you and what others are running, but is it reasonable to expect that they should have at least come a bit closer to what you guys are suggesting?

One other follow-up question. Does this statement - "Chances are they have rubber hubs and thus the 350hp rating" in response to my question about what this rating means, does this imply that I am going to spin the hub? If not, what are the implications of this?

Thanks again!

VoodooRob

[QUOTE=scottgjerdingen;4477395].......One other follow-up question. Does this statement - "Chances are they have rubber hubs and thus the 350hp rating" in response to my question about what this rating means, does this imply that I am going to spin the hub? If not, what are the implications of this?

You do run the risk of spinning the hub insert. Return your props and call Brett at BBlades. Brett will work with you and get you the best price he can PLUS he will advise of any knowledge he has on your set-up. Worth it even if he is a few bucks more. Plus I would stick with more mainstream prop manufacturers, my 2 cents.

phragle

iTrader: (3)

BBlades will get you close and send you props to try before purchasing them....... for MUCH less than cost of collecting shiny stainless shelf sculptures..

scottgjerdingen

ha, the only blades I collect are dinged beyond repair, they tend to make good paperweights (although they take up a fair amount of space). I tend to view these almost as battle scars :-) ...don't get me wrong, over 40 years I only have 2. I have more busted outdrives than I do props..geeze that's not good, had not thought of it this way before, maybe I should consider aluminum props:-)

LOTOWONTOPGUN

Pull the running gear soon and have Glass Dave do the transom work for you. If your timing is good you get it back home before winter gets to your door.

GLENAMY 242SS

iTrader: (1)

Scott, WAGS382 has a set of 30 pitch Bravo 1's in the swap shop.