33 Executive Fiberform

pole position

Petty Officer 2nd Class
Joined
Dec 14, 2008
Messages
156
Recently bought a 1979 Executive Fiberform with twin 454 mercs fwc, 1 1/4 shafts, 1.91 inboard transmissions.They are not the original engines. Anyone have an idea on what size props should be on this boat?file:///home/brian/Pictures/executive.jpg
 

hwsiii

Commander
Joined
Jan 25, 2009
Messages
2,639
Re: 33 Executive Fiberform

Brian, welcome to Iboats prop forum and we will try to help you as much as we can but without more information no one can help you, and I will tell you I need more information than anyone else. But if you would like my help fill this form out and I will help you as much as I can, if you would prefer to not go to this much trouble there are other people who will gladly help you.

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 maximum 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. manufacturer 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 then do the same thing on the motor and turn the motor until the tape lines up with each other on the prop, 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, use a board under the keel and stiking out to the anti ventilation plate for a referene
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. Make sure you trim the prop up until it starts ventilating and then just trim in until it quits ventilating. If you do not have a tach you can buy a Tiny Tach for $ 50
RPM ___________ Speed ___________ No. of people ____________ Gas ________
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 foregoing 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
 

pole position

Petty Officer 2nd Class
Joined
Dec 14, 2008
Messages
156
Re: 33 Executive Fiberform

I'm not sure of the current prop sizes,I think they are 20x20. The boat is 33 feet long with a beam of 13'4". It had about 180 gallons of fuel 3 people on board and topped out at 26 knots on gps at 4000 rpm. It has no keel and a moderate v hull. The problem is that these props run about7/16" off the bottom of the boat. The engines should turn 4400-4600 rpm.
 

hwsiii

Commander
Joined
Jan 25, 2009
Messages
2,639
Re: 33 Executive Fiberform

Pole, most of the people here trying to help don't know much about inboard motors and the specifications needed for the proper propping of them.


H
 
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