Trolling valves - why isn't there a better way?

UnkleJ

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This is just sort of a open ended question, I am curious to see what people think...I was just reading the "42 H&H wide" thread in the builders forum, which turned into a debate on the pros and cons of trolling valves. It got me thinking ( I know, dangerous!) - why is it that the trolling valve seems to be the only widely accepted means of slowing down the hull speed at idle for boats with big diesel power? It just seems kinda low tech to use what basically amounts to clutch packs that you can lock up to run at speed or allow to slip to reduce prop Rpms at idle ( assuming my understanding of how trolling valves work is correct). Maybe there is a really good reason and I am just missing it, but why don't these boats use 2-speed transmissions to do the same thing? You could run on low gear (which would have a very high reduction) to slow the prop down for operating at low hull speeds for trolling, docking, etc, and then you could use the high gear, with your typical reduction for operating at higher speeds... I don't know, seems simple, but I'm sure there's a reason it's not, or boats would be set up that way. Just curious what people think or if people have seen it done.
 
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Badlatitude

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They make 2 speed gears. I also cannot understand the reasoning.


People want rocket ships because they are in a hurry. Then they use a trolling valve which basically uses hydraulic pressure to destroy their transmission
 
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Toolate

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Can you post a link to a 2 speed marine gear?

What is the average speed reduction from a trolling valve and what would the gear reduction be in order to achieve that?

SLowing a boat from 7 kts to 2 might require the average diesel boat to go from 2:1 ratio to what, somewhere between 6:1 and 8:1? Something like that?
 

plowin

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One of the few things that I do like about all this electronic stuff that has come along is the trolling valve setup. I have the cummins smartcraft system in my boat and while using the trolling valve if you exceed the engine/transmissions desired trolling valve rpm the clutch will lock up and fully engage preventing you from blowing the tranny. People use the valve for different reasons, I for one, use it to silently slip the boat into gear when I do not want to spook fish that are very close. Not so much for trolling or close quarters operation.
 

hntrss

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Used properly, I really don't think they do any damage to the transmission. Basically every sport boat built uses them. A charter boat friend of mine with a 6cta and zf gear has over 10,000 hours on his gear and probably uses the trolling valve on 75% of his trips. You just need to be religious about using them properly and it pays to make a locking mechanism of sorts to assure they don't get engaged while underway. To troll fish like striped bass , you really need to get below 3 knots, most boats with single screw are not capable without either a valve, or dragging something (which is a pain in the ass).
 

Badlatitude

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they also make a setup that there is an electric solenoid and a micro switch which you adjust to trip on your mechanical linkage as a safety cut off
 

Cfood

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Used properly, I really don't think they do any damage to the transmission. Basically every sport boat built uses them. A charter boat friend of mine with a 6cta and zf gear has over 10,000 hours on his gear and probably uses the trolling valve on 75% of his trips. You just need to be religious about using them properly and it pays to make a locking mechanism of sorts to assure they don't get engaged while underway. To troll fish like striped bass , you really need to get below 3 knots, most boats with single screw are not capable without either a valve, or dragging something (which is a pain in the ass).

Exactly. We have a small lanyard with a clip to "fool proof" the throttle for mechanical shifters. Also have one to keep the valve off and avoid an accidental engagement. With electronic shifters its bullet proof
 

Toolate

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I looked all over that listing and dont see the other ratio tho.

If you had 6:1 gear or so, wouldnt you really be at high rpms to get to say 5 kts too? Normally at say 600 rpm idle the boat in question would be running 6/7 kts with 2:1. Then to switch to 6:1 and you would need triple the rpms to keep the same speed which means 4 kts would be 1200 rpm or so. Very high for trolling so it seems like you need the variable speed of the clutches to control your rpms and speed and no fixed ratio would work esp when current and wind/loading start to play.
 

Tuckerman

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I was on a big sporty that had electronically controlled gears he could dial the shaft rpms from the helm. A 55' boat that could troll at one knot. Around the dock is a pleasure with those gears.
 

hntrss

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I know when I repower there is a trolling gear going in. Right now I drag a sea anchor midship, and it works well, but if you want to make a move, you have to pull the whole mess in the boat first. Good for now, but not for long!
 

lobstercatcher

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One of the reasons I have the high rpm diesel. It goes slow and it goes fast all on its own. Fast enough for me anyway , I was more concerned with slow.
 

captainlarry84

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At the NY boat show years back Cabos played with the 2-speed gear. They just were no strong enough to work so they drop the idea. If you plan on using a trolling valve it is just for that. Going down a canal with a trolling valve on could be dangerous. Should you have to speed up for safety reason with the valve on...kiss that gear good by. The valve is only good in open water for fishing needs. On windless days for drifting baits for tuna, shark & Strip bass the valve is deadly. On a cannel slow zone I just take the boat in & out of gear.
 

md2020

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Love the troll valve, use it all the time....one issue, some ZF gears will 'chatter' when using it at certain RPMs. Seems to be more of an issue when going into it with a stiff wind. Called ZF and they had me switch over to Donax TD Hydraulic Fluid, it's def. cut down on the chatter.
 

lobstercatcher

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At the NY boat show years back Cabos played with the 2-speed gear. They just were no strong enough to work so they drop the idea. If you plan on using a trolling valve it is just for that. Going down a canal with a trolling valve on could be dangerous. Should you have to speed up for safety reason with the valve on...kiss that gear good by. The valve is only good in open water for fishing needs. On windless days for drifting baits for tuna, shark & Strip bass the valve is deadly. On a cannel slow zone I just take the boat in & out of gear.

I remember leaving Freeport and that canal when I was a kid. Seamed like it took forever. I'd hate to try to do it with a boat that couldn't go slower than 7 knots. I would probably sell the boat or go find a slip that it next to open water.
 

captainlarry84

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I junked that push pull lever for the trolling valve & added a single lever Morse control. The Morse control allows you to really tailor the gear when in use. I also added a VERY large red light to the dash so I know when it is in use. The red knob all the way to starboard is the trolling valve & the red light is above it.

March photo 06 122.jpg
 

Jay c

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I've got the single lever morse as well for valve. We keep a line tied to the dash - before you push the throttle, you best make sure the valve control is tied in place.
 
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