controls question

HI all,
I am new to the forum and thought I would jump in. I am beginning to research my first trawler purchase and I found a boat I like but it has two stations, each with pneumatic dual function controllers for the engines. I have seen these for sale online but I have not seen another vessel with them, not have I found any discussion. Almost every boat has mechanical single function controllers if it has dual stations. Anyone know anything about these pneumatic controllers? Thanks!

Welcome aboard!
Pneumatic controls means an active air compressor or tap off the engine turbo to make them function. We don't normally see this on rec boats under say 50 ft. Is this a large commercial vessel?

Those sound like Hynautic controls, very reliable and smooth.

no, it is a 42 ft Jefferson. I have not found another Jefferson (even though there are a bunch out there) with this setup. But I don't see where it was changed, unless they change the entire cockpit dash above and below.

Pneumatic controls were common before hydraulic transmissions. Nowadays, if not cable controls, they are generally electric. Fairly old boat?

Ted

Here is a pic.

1990 jefferson 42. trying to figure out how to post pic.

They look like this. 1990 Jefferson 42

Those look like Kobelt, big overkill for that vessel. Well regarded for commercial

Kobelt pneumatic control systems for maritime vessels & industrial machinery

Everything I read said big commercial vessel. Not sure why they are on this one. As long as they are relatively reliable I don't suppose it is a negative. Thanks!!

Air controls were the preferred engine controls even including hydraulic transmissions for a long long time. Many tugs, supply boats and various other commercial boats still operate very happily with them. Electronic controls started to replace them with the more common use of electronically controlled engines, dynamically positioned vessels and pod drive azimuth drives. I must say I have never seen them on a pleasure vessel other than larger super yachts. They do require a continuous source of compressed air in order to operate. I can only imagine they were installed on your Jefferson at the request of an owner who operated heavier commercial boats for a day job and so enjoyed the handling characteristics. I must say that one of my favorite sounds in the maritime world I'd the chshhhhh noise they make then the lever is drawn back to neutral.

Kobelt makes bullet proof reliable controls. If they are working and your confident in them why change?
I don't know where you are located , or where you boat but the gremlins for pneumatic controls is water. Condensation and freezing control lines is a concern. Not in engine room but where lines go to a flybridge station. If your in temperate climates, great!

Hey, I'm an engineer and can appreciate this kind of thing, but this is way over the top for a 42.

from the manual:

In order to provide a satisfactory control system it is of utmost
importance to have a reliable source of clean compressed air
and storage facilities. Before the air enters the control system
an air filter must be provided to remove minor impurities from
the air. The filter also removes most of the moisture from the
air supply. After the filter, an air pressure regulating valve is
required to maintain a specified and constant air pressure.
We recommend the installation of a lubricator in the air
system which provides an oil fog for the lubrication of all
moving parts within the system. See illustration #1.

So, does this boat have a redundant, and alarmed source for this air supply? Are there other shop air appliances on this craft?

Cool that it has them as long as the support air system components are maintained. Loss of control is not fun.

This has been great information. I have not purchased the boat yet, but if we get to a price agreement I will make sure my surveyor is familiar with these types of controls and can answer the questions you have provided above! And make sure he can show me how to properly maintain... ;-)

Sounds to me like a great excuse to get a big-ass air horn.

I've been running boats with pneumatic controls since 1978. For the most part they are very reliable. But as others have mentioned air and moisture are your nemesis. Keep your compressor in top shape, air receiver (tank) clean and dry, filters and dryers in good shape.

I drain the air receiver and dryer daily when in operation. In humid warm weather you will see more water in the receiver and dryer than other times.

Test your controls before you leave the dock and before you approach the dock. Stop her before you dock her.

The biggest problem with air controls, especially quality controls like Koblet is you won't want anything else. You'll get spoiled.

You have to factor the delay in while maneuvering. My tug is 6 seconds, I've seen as long as 12.

SaltyDawg86 said:

You have to factor the delay in while maneuvering. My tug is 6 seconds, I've seen as long as 12.

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Gear AND throttle response?

Its usually a single lever so yes its gear and throttle response. The time delay is set to allow the engine and gear to stop rotating before engaging again. In a tug with a big ass engine and large heavy duty clutch and gearbox it takes a few seconds for all that rotating mass to stop turning. Many large horsepower tugs will add shaft brakes to help with this. Some don't and have a longer response time. I have seen some big weasels have 3-4 second delays even with installed shaft brakes. When you are moving large mass such as 25,000 ton barges you need to be thinking way ahead of your vessel anyway. I would doubt if this would be an issue for the boat in question

yeah, clearly on a small vessel you would not desire long dwell/transit times. I'm thinking more dockside than the 8kts underway.
I can see the benefit on pneumatic if the control distance is a hundred feet+; quite untenable for push-pull cables. Plus, it can enforce a slow execution time.

That slow response time worries me. Seems like it would be almost impossible to make corrections in a timely manner when docking.

cbowers1971 said:

That slow response time worries me. Seems like it would be almost impossible to make corrections in a timely manner when docking.

Click to expand...

Needle valves that are adjustable can modify the timing behavior. But, the complexity of the hi-rel air supply is more of a worry on a small boat. Unless you have a paid engineer on board.

I wouldn't let pneumatic controls put me off looking at a boat at least until sea trial. I suspect the response timing will be no issue.