Todd320
Well-Known Member
- Jul 21, 2016
- 1,508
- Boat Info
- 2007 Sea Ray 320DA
- Engines
- Twin V-drive 5.7L 350 Horizon
On my 320, I had a ding in one prop, so had them both reconditioned (hired someone to remove, take to prop shop, then reinstall). He asked the question why they were different sizes (18x18.5 and 18x19). I believe he works on mostly larger boats, typically he dives. I have no idea, that’s just what the manual stated. I spot checked other boats by pulling up the Sea Ray manuals, and sure enough, 08 48 DA, identical LH/RH sizes, same for a 38 diesel, but the gas version v-drive used different sizes.
My guess is on the gas, the higher RPMs exaggerate the difference in gear ratios between running one transmission in Forward, compared to Reverse, so this slight adjustment in pitch compensates for that? I noticed on one Hurth spec page, they mentioned slightly different ratios for position A vs B.
320:
48 Sundancer: identical 24x29
38 Sundancer (all were 08 manuals), gas options used 21x22.5RH and 21x23LH, diesel, identical 21x24
My guess is on the gas, the higher RPMs exaggerate the difference in gear ratios between running one transmission in Forward, compared to Reverse, so this slight adjustment in pitch compensates for that? I noticed on one Hurth spec page, they mentioned slightly different ratios for position A vs B.
320:
48 Sundancer: identical 24x29
38 Sundancer (all were 08 manuals), gas options used 21x22.5RH and 21x23LH, diesel, identical 21x24