Trim tab anode- do I need one?-gctid817193

[Guest]

I have an 89' 2050 Arriva with 5.0 Mercruiser, the fin on the trim tab anode is broken off, and I was told by a repair guy to not worry about it (I filed it off flush so no sharp edges), what exactly does the tab help with, and should I replace it?

Only issue I have with the boat is that it tends to get "tippy" when loaded close to maximum or towing heavy tubes, etc. When turning in these situations (worse turning left), the boat feels like it is riding really high in the water and will actually just tip over, even at 20-30 mph towing/cruising speeds. Is this related to the trim tab anode, or something completely different?

[green650]

Are you talking about the anode that looks like a little skeg on the bottom of your outdrive?




Or the anode on a trim tab?




The one that looks like a skeg on the bottom of your outdrive is to help counter the steering torque generated by a single prop wanting to make the boat turn. The ones on the trim tabs do nothing for handling.

[Guest]

The one on the outdrive. Would it affect the boat as described- the tipping problem?

[Pcpete]

What that fin does is compensates for the directional torque put on the steering by the propeller. Properly adjusted the wheel will stay centered while on a plane.

As to your other issues, now you understand why they put those load limit tags on boats. The center of gravity doesn't move with the bottom of the boat, it stays at about the waterline. From here a marine engineer will have to chime in to explain the how's and whys. The similar issue while towing is like leaving one cleat tied to the dock and powering on. The boat is going to "dig in" the same way a pickup does pulling stumps. Now take that resistance and extend it about fifty feet and make a turn. That load out there is going to want to drag the stern of the boat right on around. Think of it as a trailer swinging on ice and what that does to the tow vehicle. Perfectly normal, just know it's coming and plan for it.

[Guest]

"Pcpete" post=817199 wrote:
What that fin does is compensates for the directional torque put on the steering by the propeller. Properly adjusted the wheel will stay centered while on a plane.

As to your other issues, now you understand why they put those load limit tags on boats. The center of gravity doesn't move with the bottom of the boat, it stays at about the waterline. From here a marine engineer will have to chime in to explain the how's and whys. The similar issue while towing is like leaving one cleat tied to the dock and powering on. The boat is going to "dig in" the same way a pickup does pulling stumps. Now take that resistance and extend it about fifty feet and make a turn. That load out there is going to want to drag the stern of the boat right on around. Think of it as a trailer swinging on ice and what that does to the tow vehicle. Perfectly normal, just know it's coming and plan for it.

Thanks!

[Aircraftbuilder]

What I have found is that if you don't have power steering, the fin on the trim tab anode prevents the boat from being a real bugger to steer. When on plane with the finless anode, you will notice that the wheel needs to "cocked" to counter the rotational torque of the prop. The finned trim tab, as others have stated, counters this effect. I found a reference that said boats with power steering do not require the finned type.

I can confirm this because I recently changed my anodes and the kit came with a fin-less type (I don't have power steering). It took about one outing to order one with a fin. The other thing to note is that if you have a four blade prop, you might have to modify the fin for prop clearance. There are also some trim tab anodes made with an off-set for additional clearance.

I'm still a pretty new boat owner, but this has been my experience.

[Dadrock33]

Personally, I don't think the fin has much to do with anything . . . does it help? Some say yea and some say nay; I didn't miss it a bit on my 2452.

As far as the "tippy" aspect goes; if you're fully loaded, you shouldn't have an issue with "tipping" unless something else is going on . . . like maybe you're connections to the towed item are too low and actually pulling the stern up out of the water? Possible, not sure but don't see much else to make your particular boat tippy . . . . do you ever cavitate while pulling a skier or tuber? Tuck that outdrive in under the boat as far as you can and it should help . . . quick turns will make you wonder sometimes though and yes, it's always "weirder" turning left because that puts you (the driver) up higher in the air and it is more noticeable!

[RobMick]

Regarding "tipping sensation" I will get this while pulling a tube and having as few of 2 pax on the port side of the boat in my 185 especially while turn left. When I asked the pax in the stern to move to the startboard side of the boat, that sensation disappeared completely......and yes I was in "hard over" turn at a pretty good clip to throw my 23 year old off that thing....

[RobMick]

On the topic of replacing anodes or "zincs" I need to do this to my fresh water only 185. I will get the mercruiser complete anode kit. Question is, should I replace the zincs prior to winter storage or right before spring launch? Any benefit or corncern one way or another

[SteveInCal]

Hey Kevin, nice boat! I have the exact same model

Mine has power steering so I assume yours does as well. I don't have a fin on my anode and don't think one is required with PS.

When loaded up with kids for tubing, my boat gets pretty tippy as well. I just take it easy through the turns and it's fine. Figured it was just a function of the hull design...

I bought some Smart Tabs but haven't had a chance to install them yet. I'm assuming they'll make the boat more stable..

[Guest]

"SteveInCal" post=817807 wrote:
Hey Kevin, nice boat! I have the exact same model

Mine has power steering so I assume yours does as well. I don't have a fin on my anode and don't think one is required with PS.

When loaded up with kids for tubing, my boat gets pretty tippy as well. I just take it easy through the turns and it's fine. Figured it was just a function of the hull design...

I bought some Smart Tabs but haven't had a chance to install them yet. I'm assuming they'll make the boat more stable..

Steve, I'd be real interested in how the Smart Tabs turn out! Keep me posted or shoot me a message when done.