BMILLER wrote:I have erratic tachometer readings (at best). Would it make sense to install engine sync gauges and not totally replace all the tachs. Seems as though the port tach at both stations is hanging, etc. Flybridge one starts to work after running a while and lower stabilizes when I turn on the instrument panel lights. I can't find any loose or corroded wires or connections.............yet. I thought maneuvering would be MUCH better knowing which engine is faster/slower. Now its a nightmare. I can't tell by the sound of the engines?
Tachs are Apelco..........OEM I presume.
Just wondering if this would be a easy way to "make do"..?
'78 F28, 318's
Okay 'B'... forget the 'B(S)' you have seen in some of the previous posts.... some people have a tendency to lose focus and get a bit off track......
You can usually tell by ear if you are in synch or not, but it might take a bit to develop the skill. Hard to depict here, but if you hear a repeating droning sound (..........ooooooooOOOOOOOOOOOoooooo.....) - can't really include an audio clip, but assume the dots are quiet, the o's are louder, the O's are louder still, and the cycle repeats... - that means the engines are out of synch. Don't really know if it is differences in the props, engines, or just exhaust you are hearing but if you hear the WoWoWoWoW sound, you are out of synch. The faster the WoWoWoW happens, the more the speed is off... the slower the WoWoW is the closer you are to synch. This is a LOT easier to hear while running at higher speeds.
At speed, being in synch is best as it is easier on both engines, the running gear, and the hull, and it is easier on the steering - you are not fighting the engines. It is also safer as you have consistent push on both sides, so if you launch off a wave or dig your bow into one, all you need to worry about is proper steering and not side effects of different power torquing the boat sideways on you.
In close quarters, if the engines are in synch it makes it easier (or at least more predictable) to maneuver. Again, with the same thrust on both sides, the boat won't corkscrew on its own.... by shifting forward/neutral/reverse and / or steering you will be in complete control.
I would recommend replacing ANY instruments you don't trust. If port and starboard are behaving differently, you can try swapping them to find out if the problem is the instrument or wiring/sending unit (if the port tach is still messed up after swapping port for starboard, then the problem is sending unit/wiring/ground; if the problem moves to starboard, then it is the instrument). I have replaced all mine with Teleflex Red International instruments after a lightning strike knocked out half of them.
I also had a new set of Engine Synch gauges installed (also Teleflex Red Internationals). At low speeds near the docks, you might not be able to hear the difference in engine speed, so the synch is the best way to tell for sure. Since throttles and idle stops on the carburetors may get out of whack over time I tend to get my engines synched up as I approach the marina - slow to idle speed, tweak throttles until both engines are idling the same (per synch) while the wife is getting fenders and lines ready, then enter the marina.
To comment on some of the other comments : there is a time and place for adding power while in close quarters. Too many yahoos think it's the macho thing to do to hit the slip doing 5 knots and miraculously stop in time... and too many more yahoos do it because they don't know any better. If you are not fighting a current or massive winds, you don't need throttle. The more throttle you apply, the faster the boat will move; which means the more throttle or force you will need to stop it, or the more damage it will do (to the boat, the dock, or the crew who try to stop it). SLOW is your friend. I love to watch the guys who hit the slip at 5 knots, ram the dock in front of them, and blame it on some crewmember who "didn't tie the spring line off in time". These are the boaters I avoid on the water because they are dangerous, reckless jackasses who don't know what the *H* they are doing.
A few years back I saw a guy with a 40' Sheppard flush deck (I think - it was a while ago). Decided he need to spin the boat really quickly in a confined channel, so hammered shifters and throttles in quick succession. Probably turned the boat in half the time it would have taken if he was just idling and split the gears, but almost threw a bunch of his passengers into the drink in the process as the hull lurched forward and backwards / side to side every time he hammered a control. If the dipstick that used to run Skid Row out of Toronto back in the 70's/80's is on this forum, I am talking about you.
Above I said I slow to idle speed as I approach the marina... (600-700 RPM). If it's blowing hard, I might up the idle a bit (to maybe 800-1000rpm depending on conditions) before I enter the marina so the props have that much more bite when I hit forward or reverse, but I NEVER goose the throttles while maneuvering in close quarters. If the engines get out of synch, I have to try to fight/counter the corkscrew effect, which means I am not really in control anymore.
I have only goosed the throttles once in 11 years with the boat : while trying to back out of my slip on haulout day a couple of years back. The wind was blowing me forward in my slip (25-30 mph wind with gusts to 40+). With all lines off I hauled as hard as I could on the stern line - with the force of the wind on the salon windows, I couldn't make the boat move backwards at all... at most I moved it a couple of inches. Running aboard and hitting reverse didn't do any better. I had to push both engines up to 1500 RPM to back out of my slip (and then turning was even more fun!!)
Use power if (and only if) and when required. Throttle is not your friend..... control is.
My recommendation : check and/or replace your tachs, but don't trust them implicitly. Get a reliable synch setup as well.