gear ratio question

[captword]

I am currently restoring a 50 ft, 1962 huckins fair form flyer. The boat origionaly had 671's with 1:1 gears going to a 1.38:1 vdrive. REpowering with cummins. Had to go with 1.23:1 gears. Lowest gear ratio we could get without waiting 3 months. the problem that i am having is actually figuring the gear ratio to the prop. 1.23:1 gear to a 1.38: 1 veedrive. what is the ratio now? do i ad the numbers and get 2.61:1 ?
I use normal wheel calculaters like boat diesel.com and michigan props provide normally, but having a hard time with the gear ratio.
Any help appreciatted
Captword

[captword]

after 4 pages of paper and dep digging though the cobwebs of my college days i have come up with apprrorimately 1.703:1 . Launch date is comming soon and I am tryng to figure prop size, but i had to figure the motor to prop reduction

[mmd]

1.23 x 1.38 = 1.697 final drive ratio.

[captword]

Yes i finaly did remember the college stuff and came up with that. then i did it the long way to doudle check and came up with1.7031615........
Thank you for the reply. beeen a long day tryn to get stuff done in the rain. It helped having someone with a fresh mind to help

[Willallison]

How about posting some pics of the project..... Love Huckins's

[captword]

stupid question, but how?
I get sbox that pops up with a fttoaddress
not seen this b4

[Willallison]

Originally Posted by captword

stupid question, but how?
I get sbox that pops up with a fttoaddress
not seen this b4

Go to your user CP and check to make sure you are able to post images - if not conatct Jeff - I'm sure he'll happily make it so you can.
Suggest you post JPEG images - most others seem too large - particularly bitmaps

[captword]

she flies!!
did are first out of the harbor test run today. someone needs to figure out how to adjust the prop curves for a huckins. At 1900 nrpms we were doing 23 knots. didnt shove her no harder than that. going slow on the veedrives they havent been used in atleast two years. another packing of grease in the bearings, and we will see what she does tomorrow. At current calculations we are slightly over wheeled. but that was what we had on the boat when we baught her. Once i feel safe with the veedrives and can shove the throttle all the way up, I will have a closer knowledge to what prop i need. it is exciting after a long 7 months of work.
howard

[FAST FRED]

You have added a great deal to the boats avilable power by using more reduction gear, so "over wheeled"???

The 6-71 twinn engines used to be good for a Knot for every 100rpm
1800 rpm = 18K

2100 rpm = 21K,

Sounds like youre doing just fine ,

but a EGT in the exhaust stack , and a max rpm pull check of the engines will tell.

FAST FRED