Prop advice appreciated.

[Gravity]

Hello, I have an '86 Chaparral 20' "198 c xl" deep vee cuddy. Boat weighs around (best guess) around 4k. Powered by a 5.7L, 350ci chev. with a q-jet. which is mated to a gen 1 alpha 1, turning 1.84:1 gears. I have tried an alum. 3 blade 21p (4 adults with gear and 35 us gal of fuel) and have excellent hole shot and torque, with about a 5300 rpm max at gps 40 mph. I installed a 3 bld 23p alum. and with 5 adults and 45 gal. of gas it takes way too long to plane out, but after everybody steps forward on boat it finally breaks over and will hit a gps speed in excess of 50mph at 4900 rpm (ran out of room, too many other boats nearby). Both current props are in need of some repair. For me to get either prop repaired Im looking at around $80. I'm wondering what you all thought about me installing a new 4 blade alum 23p such as ( http://boatpropellers.iboats.com/Me...r=1986&**********=773233239&*******=650954847 )? The boat does get beached and would rather leave the prop alum for sacrificial sake. The usage of the boat is 60% water toys with maybe a 40% "just cruise around" split. Would this be a decent compromise between the two? What am I going to sacrifice? I'm just thinking if I'm going to spend $80 plus, might as well spend $100 (elsewhere) and get something that's inbetween the two... what are my consequences going to be???

Thanks for all of your help and thoughts.
Regards, -MV

 

[tysonnathan]

Re: Prop advice appreciated.

for water toys and cruising i would stick with the 21. 40 is pretty good on the top end for that boat... there is nothing i hate more than a boat that doesnt want to plane. I would not spend the $ on a new prop and risk having a boat that wont plane w/o the help of passengers shifting their weight. maybe you could see if you could test run a few props if you find a good shop. the extra blade on the 23 will help, but if it doesnt work your gonna be out some cash...

 

[tmh]

Re: Prop advice appreciated.

Something doesn't seem right here. If you're getting to 4900 rpm WOT then you should be fine on hole shot. Check the tach somehow. Also, isn't the Alpha one gear ratio 1.47-1.62 for a V8 engine (I've seen that range discussed, mine is 1.5). If so, the 1.84:1 gear box may be a problem in getting the desired performance.

Smart Tabs would help you plane out better/quicker I think - maybe more than a different prop. If your tach is correct, then the 23" isn't "over propped" but also doesn't give you good water sports performance. maybe a 22" 4-blade would do the trick? SS would make a big dif. with your boat/engine set up so you may want to reconsider SS.

 

[Gravity]

Re: Prop advice appreciated.

Tyson, I called around here locally, (Seattle) and no one stocks (and most dont even sell) 4 bld alum props, so I'm SOL for testing one out. Good thought though.

Tmh, yes most v8 ratios are 147 to 162. I replaced my upper about a year ago (when I had the original 5.0L 305 pushing the boat around). I opt'd for the 184's then because it wouldnt even dream of planing out (at then a 6,000 ft elevation). Now I live at sea level AND have since replaced the 5.0 with a 5.7 due to my foolish neglect over the winter. I have compared my recently replaced tach to a friend's snap-on timing light digi tach and was within about 100 or so rpms. I just looked up the smart tabs... might not be a bad way to go. I can get the 4 blades solas prop for $96 including shipping. I am hesitant to go SS because Saturday I novicely trashed my 23p beaching near some river rocks on the Columbia River. I think, for me anyway, I'll stick with a $96 prop until I can prove to myself that I can be responsible with a $360+ prop.

I'll consider the tabs, for sure, but I'm going to need a new prop (new or rebuild) either way I go.

Thanks for the advice.
Regards, -MV

 

[tysonnathan]

Re: Prop advice appreciated.

not a whole lot to lose for $96... and i feel ya on the ss... i still havent got the guts to do it. where i boat there are too many objects to trash one on...