1974 43DC Propellers

[micky]

What size and pitch does a 1974 43DC with 6-71n detroits use? Right now when I put the stbd engine in gear she reacts but when I put the port engine in gear I have to give it some throttle to feel it moving.

 

[Will]

Well, this sure is an unusual problem. Is this something new or has it existed forever and you're just becoming annoyed with it?

You could start by verifying with an external tach that your engines are idling at the same RPMs? If so, are your prop shafts turning at the same speed in idle?

It would take quite a bit of difference in prop size to create the symptom you describe.

Will

 

[Bill Allen]

My 73 runs 24x26 maybe a little bit much but almost perfect. I run 80 injectors but rarely run faster then hull speed. Putting it in gear it doesn't leap foward and to manuver it a little bit of throtle may be required. In a current like up here in brielle you can't try and sneak around at idle and throtles are required to make the boat do what you want. I have 6-71N's. Bill

 

[micky]

My dad bought the boat on April and we feel what I described when we put it in gear at the dock or coming out of the dock. We have taken the boat out just once and I haven't been able to dive under it. The boat has a set of spare props that I'm going to have scanned. Would 24 x 24 be a good size and pitch for this boats?

 

[eze2bme]

My 1979 43DC with 6-71N's has 24x24 - and the Hatteras owner's manual says 24x24.

 

[dsharp]

The prop size will depend on what reduction gears that you have. The only way to tell is run it wide open with a clean bottom and see what rpm it will turn. You may want to check the oil pressure in the gear and make sure the cables are adjusted where it goes all the way into forward. The gear may be slipping.

 

[micky]

With a dirty bottom, very dirty racors (found out after the run) and non working trim tabs (now they work) we hit 1900 rpms but at that rpms we were moving at 9.5-9.8 knots.

 

[Jaxfishgyd]

I have 24X24 props...... but at 1900 rpm I do 13-14 kts.... usually run mine at 1100 rpm which gives me a cruise of 8-9 kts.. Even with all the stuff we have onboard

 

[micky]

I saw 9.5-9.8 knots all the way from 1500 to 1900 rpms. I'm going to clean the bottom and now that the tabs are working take her on another trial.

 

[dsharp]

You would be surprised how few barnacles and slime it takes on the props and bottom to kill the boats speed. I think that engine is governed at 2300 rpm and you need to be able to turn the rated rpm or the engines will be over loaded. Like you said you have to run it with a clean bottom to tell what you have.