tahoe 215 deck boat

medicfireman

Cadet
Joined
Aug 3, 2009
Messages
19
i need propellor help.
i just bought a tahoe 215
4000lbs w/ 5.0 mercrusier
it came w/ a 23p-alum 3 blade--max rpm wot was 3100 at about 30mph.
exchanges it for 19p aluminum 2 blade--4200 wot at 51-52 mph

we usually have 50 gal fuel,20-30 gal fresh water and 5-6 adults
and primary use is tubing

i just hate to go as low as a 17p--
but i do want a four blade- this is a brand new boat- i would have figured the factory would have gotten closer than they did
any help is appriciated
 

hwsiii

Commander
Joined
Jan 25, 2009
Messages
2,639
Re: tahoe 215 deck boat

Medic if you have a 1.62:1 gear ratio I don't believe you are getting 51 MPH out of it maybe 41 MPH but not 51.


H
 

medicfireman

Cadet
Joined
Aug 3, 2009
Messages
19
Re: tahoe 215 deck boat

thank u for the response, i am just going by the speedo-
this is a brand new boat--i have always had fast bass boats or slow pontoon-
i am new to the deck/ski boat- if it is not 50 then it is close b/c it is moving-
but i dont have the hole shot or rpms i need-
is it unusual for a deck boat to need a 17p or for a boat to come so far overpropped,..
thanks
 

jokaj

Seaman
Joined
Sep 23, 2008
Messages
73
Re: tahoe 215 deck boat

I have a Tahoe 228 deck boat. it came with a 14.5 x 19 prop which works well with my wife and two kids. Full tank of gas 48 gal and 22 gal water. We go out of Lake Mead. Add three more adults, very hard to plane. I either moved them forward or it takes forever to plane. Got a 17" prop and it works well. Haven't tried it with more people on board. The speedometer read around 45 mph with my wife and kids.

At powell 3600+ ft, 19" prop was slow to plane with a full tank of gas. 17" prop was nearly impossible to plane with a full tank and a total of10 people. Had to move two adults to the front in order to get onto plane. Haven't tried a 15" prop...........

joe
 

medicfireman

Cadet
Joined
Aug 3, 2009
Messages
19
Re: tahoe 215 deck boat

thanks for the info, that helps out alot.
we are at sealevel here in shreveport- i think i am going to get the 17 4 blade.
i think one of my problems- i have never ran it unloaded-we are always at least 6 people heavy. i was just worried about going that low in pitch.
the tahoe folks are saying 51-53mph and i am very close to that but like i said my rpms are around 4000 and hole shot is terrible
thanks again
 

hwsiii

Commander
Joined
Jan 25, 2009
Messages
2,639
Re: tahoe 215 deck boat

Medic, I ran the numbers on your 19" pitch prop with 2 peopleon board and at 4,200 RPM if you were running 51 MPH you would have a prop slip of -9% and that is impossible with a 1.62:1 gear ratio, it should be closer to a minimum of 10% and 42 MPH or a real tach RPM of 5,100 and a speed of 51 MPH. So either the prop is not a 19" pitch, or the gear ratio is not 1.62:! or your tach is wrong and you are running closer to 5,100 RPM than 4,200 RPM. Here are my numbers.


Prop Slip

medifiremanPropSlip.jpg



H
 

medicfireman

Cadet
Joined
Aug 3, 2009
Messages
19
Re: tahoe 215 deck boat

thank you for the numbers,
from what i have noticed on here- you are usually dead on.
i am gonna try 17" 4 blade-if i am doing around 42mph at 4200 rpm
then what should that do for me?
i just finished my break in 20hrs , i guess i need to run this thing with just me and not the extra 6 people and fuel and water...
thanks again
 

hwsiii

Commander
Joined
Jan 25, 2009
Messages
2,639
Re: tahoe 215 deck boat

Medic, I would NOT purchase a new prop until you check the tachometer, you would be amazed how many are wrong when they are brand new. Wait until you have time to check the tach and use a GPS for speed until you buy a new prop. All you need to check the tach is a hand held unit while you are running the boat.
If you will fill out this form for me I will do some further analysis and maybe I can come up with a more precise answer.

Iboats Boat and Motor Info
1. Year, make and model of boat
2. Length, width and base weight of boat, look for boat decal on back of boat
2a.What is the recommended HP for your boat
3. Number of people and gallons of gas normally on boat
4. What do you use the boat for
5. Is it a Deep Vee and if so how many degrees of deadrise
6. Year, make and model of motor
7. HP and gear ratio of motor IMPORTANT
If you don?t know the ratio, you need to pull the plugs out and put a piece of tape across the prop and the lower unit and then cut it between the prop and the housing and turn the motor until the tape lines up with each other, it is easier if two people do this, so one can watch the prop while the other counts the revolutions of the motor
8. Manufacturer?s recommended Wide Open Throttle (WOT) range
9. Anti-ventilation Plate height above keel of boat if it is an outboard in inches
10. Is it a bass boat or does it have a pad bottom
11. Does it have a hydrafoil, dolefin or trim tabs
12. Make, model, diameter, pitch and whether SS or aluminum prop
13. WOT RPM and speed from your current prop and how much gas and how many people were in the boat for the test data and is the speed by GPS. If you do not have a tach you can buy a Tiny Tach for $ 50
14. Are you at sea level or a higher elevation, give us the elevation in feet
15. Has your motor been tuned up lately and have you checked that the carburetor butterfly is opening all the way, checked compression, and looked at the plugs and checked spark, all of the forgoing could be the reason your prop is not attaining full RPM
16. How long has this prop been on the boat and why, at this time, do you think it is the wrong prop
17. Does the prop show any damage that you can see
18. What problems are you trying to cure or what are you looking for the boat to do that it is not doing the way you think it should or to your expectations
19. If you are trying to attain a better cruising speed and fuel savings or trying to attain a faster speed I will want you to take your boat and run it with 1 or 2 people and give me the RPM and speed readings starting at 3,000 RPM in 500 RPM increments all the way to WOT.

REMEMBER, The numbers I give you will be NO better than the information you give me

The only thing I ask of you is to come back and give me a report of WOT RPM and speed for my database.


H
 
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