Trolling Gear - How to?

[Pnwwannabe]

Hi all - I have a couple of basic questions about Trolling valve (on a 1979 Tolly with a pair of CAT3208M). I have never used it - and don't know when it was last used. (1) Any recommended inspections I should perform before giving it a try? (2) Is the trolling valve to be engaged before putting the engine in gear? (3) Bets practices operation - (a) Is there any recommended time limit? (b) Should the other engine be run in neutral while the Stbd (with trolling valve) is operating? I have read some other threads but not satisfied myself on these questions yet. Thanks for your insights!

 

[O C Diver]

While I know what they are, I can't help you with information. But, you probably want to identify the manufacturer of the transmission and the model number as that may be pertinent.

Ted

 

[Gdavid]

In general, know that a trolling valve is allowing the internal clutch of your transmission to slip by reducing the clamping pressure on the plates via reducing flow. So the less you use the valve, the less wear you are making on the clutch plates. I would not assume the valve is set up properly, use it minimally.

I charter fished in the Chesapeake bay for years where we troll frequently as slow as 2.8 knots for striped bass (rockfish as we call them). When I fished, starting in the 90's, the 3208 was a common engine, in turbo or turbo and aftercooler configurations in 35-46' boats. We generally slow the boat to idle, and then engage the valve (with motor in gear) as necessary to reach the target speed. We dragged so much gear in the spring, that it would slow the boat by up to 1/2 knots alone. By gear I mean as many as 24 rods with umbrella rigs and twin 4' planner boards. No restriction on time of use, so e days we trolled for 7 hours.

I believe twin disk transmissions were the most commonly used behind 3208 engines.

If you have twins, test how the boat steers with only one engine (valve restricted) first, but just shut the other down. We had no interest in wasting fuel (money) but make sure your steering is adequate as well as your battery charging.

 

[Tired Trawler]

Greetings!
I have installed several trolling valve kits on Twin Disc marine gears for another engine company.
The Twin Disc distributor insisted that an additional cartridge type oil filter be installed with the trolling valve kit.
If you check your gear oil hoses connected to your gear cooler, the filter canister, if fitted would be installed inline on one of the hoses.
If you decide to use the trolling valves, filter service would have to be included in your service schedule.
Filter cartridges were available from Twin Disc.
Be extremely careful when reinstalling the top cover on the filter canister, use a new gasket, check for oil leakage after startup.
Hope this helps,
Good Luck!

 

[Mac2]

Comment on twin disc if you have them. You can shut one engine off, but the shaft/prop will freewheel. This won’t harm the TD but could be a problem with the shaft seal depending on the type you have and how it’s lubricated i.e. it relies on water cooling from the engine. At such a slow speed it shouldn’t matter, but several hours of trolling could be an issue to consider.

 

[ranger58sb]

We generally slow the boat to idle, and then engage the valve (with motor in gear) as necessary to reach the target speed.

We had manual trolling valves on ZF gears in our previous boat, procedure was ditto. Instructions said to stay below 1000 RPM and don't shift in and out of gears while trolling valves were engaged.

Engines idled at 600 RPM, and that still gave us ~4-4.5 kts on one engine.... so the valve got us down to just under 3 kts. ZF said OK to freewheel the other gear at those RPM, and we had cross-over lube on our drip-free shafts. Sometimes wind and waves meant we had to use both engines, with valves on, to maintain steerage.

Our current boat has Twin Disk gears with electronic trolling valve controls. Weren't working when we got the boat, finally solved that last summer... but then we haven't had much of a chance to try them out, yet.

-Chris

 

[Pnwwannabe]

Thanks all for the feedback! Sounds like putting engine in gear then applying the trolling valve (I.e. relieving some of the pressure to allow clutch slip) is the right procedure. It seems twin disc is the most likely. Will take a look for the added filter. I do have PSS dripless shaft seals so will consider the risk of letting it free spin if trolling for extended period. Love this forum. Appreciate your experience!

 

[Wtrguy]

Does anyone know what percentage of used trawlers are equipped with these valves? With over 200 hrs. invested in in the last few months looking at boats online, it seems there have only been a handful equipped with trolling valves, or at least advertising it.
Thanks,

 

[Gdavid]

Does anyone know what percentage of used trawlers are equipped with these valves? With over 200 hrs. invested in in the last few months looking at boats online, it seems there have only been a handful equipped with trolling valves, or at least advertising it.
Thanks,

I would guess less than 1%, most trawlers have a pretty slow top speed, so their idle speed is usually 3 knots or less and this suits the needs of most any activity you would do for extended periods of time.

 

[Wtrguy]

Thanks for the verification.
Also, they seem to be unforgiving if mistakes with the throttle are made. It seems like towing a sea anchor or some sort of drogue chute would create enough drag to slow the boat even further if needed. Or does that create other problems?

 

[ranger58sb]

It seems like towing a sea anchor or some sort of drogue chute would create enough drag to slow the boat even further if needed. Or does that create other problems?

Another "it depends." Towing long can interfere with the bait presentation, and may or may not be susceptible to tangles... while towing short can degrade performance.

-Chris

 

[Lepke]

I was a commercial troller. Sometimes you need to troll very slow because of currents. You can have a surface current going one way and a deeper current going in a different direction. With twin screw, if you can stop the unused prop, that will also work as a drag. Most newer hydraulic transmissions can't let the prop freewheel. W/o the engine running there is no oil going to the clutch plates and rear bearing. Fishermen usually have a way of stopping shaft rotation. One way is several wraps of line, maybe ten, tied off somewhere solid. Others used a disc brake and caliper. Some use a big pipe wrench, but a HD strap wrench is better - it doesn't leave marks.
If you're going to drag a drogue of some kind, make sure it's fastened to something strong. The usual yacht cleat, fixed to a fiberglass deck is not enough.
I used flopper stoppers set to also produce drag. On rare occasions I also used large drogues, and sometimes adjusted the engine governor to 400 rpm.
To set your trolling speed, set 2 poles with bait, lure, etc., one on each side as far out as possible. Make sweeping S turns. If fish come on the pole on the outside turn, your going too slow. On the inside, too fast.