Tommy Drake, what do you think?

[Capt Dick Dean]

Tommy- I have been getting and sending personal messages thru my mail box from this site and here's the story.

There is a Bahia Mar east of me somwhere in the Hamptons that is a special boat. Seems the boat was a gift from Richard Bertram to Ray Hunt. The present steward is connected to the Hunt family and now has the the boat. The special part is that the said boat has THERMOGLIDE transmissions. So what? Well there is an "overdrive" gear that when engaged makes the boat go 4 to 5 knts faster. For example 3000Rpm showing 23knts and then the overdrive is employed goes 27 knts. Mind you that the rpm is still at 3000. This makes the top end 42knts.

You know, if I had this setup, I would enjoy a 20 percent fuel savings.

So, Tommy, as the Historian -- What?

[bob lico]

i should think it was powerglide a two speed transmission used by chevolet up to 1969.torque limited by main shaft strenth if modified will go to 500hp.used in a boat would have to have cooling and in a bertram total lenth of power train would have to be considered--tight fit with 454 but bellhousing will match up to gears a big plus.dick it is a long story i will not get into but you would come up with a slight advantage but not with the gear ratio indicates 11/2 and 1to 1 don`t work that way unless you have torque to carry it.-------------------bob

[Tommy]

Capt. Dick,

Your post about the over-drive transmission is the first I have ever heard of in an old Bertram. None of the old literature I've seen makes any reference to this unique application. I've often thought that it made sense to have a lower gear for getting out of the hole, and a higher gear after she's on plane. Most of us remember the strain of getting up on water skis, and the ease of gliding along once up. Several years ago the concept of mass-produced two-speed transmissions in boats was all over the trade magazines, but I have not heard any rave reviews about the durability of these units. Bob's post was informative.

How about it, Bruce, why isn't there mass appeal of the two speed transmissions in marine applications?

Tommy

[JP Dalik]

ZF's in production of a unit. Guy I know has them in a Cabo. Full throttle on plane, back off hit the switch, trans goes clunck and throttle back up. Had the boat a few years now. Yanmar engines. Like Vic says "the enemy of good is better"

[John F.]

I don't get it. Boats are propped to achieve a certain recommended rpm at WOT, so that the motors aren't lugging along at cruise. It would seem to me that with a multiple speed tranny the boat would still have to be geared so that, in the "high" gear, the motor could achieve the same recommended rpm at WOT. That's where we are now. So maybe we could get a better holeshot? I'm missing something here. What is it?

[In Memory of Vicroy]

The sales pitch is hole shot, period....at a high price and that "clunk" Bruce mentioned is gonna turn into a "clank" sooner rather than later. I quizzed the ZF guy one year at the FLL show about their two speed gears and he was giving me more double talk than Hillary and Edwards combined. Dumb idea.

I built a mud boat one time, used an old 16' Terry f/g bass boat and put a Pinto engine and auto trans. in it, four speed. Ran good for a short while, and when the transmission shifted up a gear the engine did not like it a lot. A mud boat is a Coonass contraption that uses high hp with a radiator cooled auto engine to drive a big prop thru mud and make a little boat go where it should not. Uses a lot of grease zerks in the drive train.

UV

[Rawleigh]

So when the engine quit you were stuck in the middle of an alligator and snake infested mudflats? Doesn't sound like a good experience!

[In Memory of Vicroy]

Rawleigh, real Coonasses only worry about getting there, getting back is a bonus. Then a Coonass from here in Baton Rouge named Coco (last name, related to my family) invented the Go-Devil, a big Briggs air cooled motor with a 10' long drive shaft that mounts like an outboard on the transom of an aluminum flat boat. Made the ducks all hate us....a Go Devil will go in no water, just a dew, better than an airboat....now some guy has come up with a Gator Tail that is more hp, bigger prop and will run thru roseau cane, a kind of cane you saw at Port Eads.......getting too easy some say, with these things and robo decoys.

My son, Capt. Brent, sent me a pix of a huge 9 pt. buck (225#) he whacked this morning.....email me if you want to see what a natural born Coonass can do with a rifle...think he was on Daryl's place.

Life is good, I smell deer sausage.

UV

[JP Dalik]

John,
The way I understand the set up. The Yanmars work real hard at lower than cruise rpm. Unfortunately we spend alot of trips below cruise rpm. Albeit sea state or time of departure (full cruise in the dark could be bad)
In order to maximize cruise and still get WOT while allowing the boat to get on plane a 2 spd gear box was needed.
I believe that there is a recommended rpm operating range.
Not sure if this gear was singular to a Yanmar installation with the higher rpm or if they have been used with the Cummins as well.
Don't think I like the idea, slam shifting a crash box at sea. Hope the solenoids don't get stuck.

[bob lico]

at one time around the 1980`s the powerglide were almost worthless then dragracers and boat people a cheap fix for a expensive problem.they could be found in junkyards all over the nation.moroso made a mainshaft and b&m made the valvebody and wiffle clutches together you had a solution for a not to heavy object to move be it car or boat.like i said the bolt pattern matches both small block and big block chevy.actually 265 ci to 502ci so in a 31 bert you take out the b/w-71 and put in the powerglide slightly longer but much lighter.yes it help at trolling but w/o would be the same because the torque and rpm should be match to the prop.like i posted before a spectra cat with twin 440 yanmmars had a three speed trans did 72 cruse and 102mph w/o used as a fishing boat for the canyon work real well.other than the gear being fasten down it worked.,but in a cabo they discontinue the 2 speed after a few years.

[John F.]

OK--hole shot or at less than cruise to optimize rpms/load. I kinda' get it--motors do sound like they struggle a little in most boats when they're climbing the bow wave. I'll stick to simple in my B31--don't need the holeshot, and she'll just have to suffer along like she has been for the past 38 years at less than cruise. Speaking of holeshot--just got an '04 LS1 6-speed GTO--mid 13s and a daily driver.....

[jspiezio]

I don't know. My experience is when salt water is involved I should just KISS. That helps minimize the amount of trouble I get myself into. On paper this sounds great, I just don't want to be the test vehicle.