[AncientMariner]

Since I do not (yet) have Flo Scans installed, my less scientific approach doesn't have enough data, but I appear to be able to maintain speed and RPM without adjustment when I use my tabs to lower the bow. I know tabs add drag, but if it was much, I would think the speed or RPM would be affected as I transition through to full tabs.

I guess my question is how many of you run without using tabs and for those of you using them, how has it affected your performance or fuel usage?

Inquiring minds want to know

Paul

[ReelMagic]

I have a 38 Open w/6CTA's and use the trim tabs all the time to fine tune speed... I initially set the RPM, say to 2100, and then add trim while watching GPS speed and engine RPM... As I trim the boat speed increases and then starts to decrease. When that occurs I take some trim back out of the boat. At that point boat speed is maximized and engine RPM remains at 2100 or has increased somewhat. Works for me..... At 2100 I'm making 24.5 knots and buring less than  27 GPH..... M2C.........

[Chris Burkard]

Since I do not (yet) have Flo Scans installed, my less scientific approach doesn't have enough data, but I appear to be able to maintain speed and RPM without adjustment when I use my tabs to lower the bow. I know tabs add drag, but if it was much, I would think the speed or RPM would be affected as I transition through to full tabs.

I guess my question is how many of you run without using tabs and for those of you using them, how has it affected your performance or fuel usage?

Inquiring minds want to know

Paul

Trim Tabs can increase efficiency. While they add drag, they also add lift, there by reducing friction, up to a point. Over Tabbing, can also decrease efficiency. So how do you know when you are operating at the most efficient Tab setting? I'm glad you asked!

Get yourself up and running at a comfortable running speed for the sea conditions in which you are operating. First use the tabs to level the boat. Once the boat is running level, check your Speed via GPS. You may have to let it stabilize for a few seconds until the speed reading is constant within a few 10ths.

Now slowly add tab (press both trim buttons at the same time - bow down) for 1 second at a time and watch your speed. Let it stabilize. If your speed increases, add tab 1 second at a time until your speed begins to decrease. Once your speed decreased, back off the tabs to where you achieved the highest speed. You are now at the most efficient tab setting for your current RPM, sea-conditions and vessel loading.

Every time you change direction or if the wind and sea-conditions change, you will have to repeat this process. Many of the Tiara vessels operate more efficiently with a little tab. How much tab depends on wind, sea-conditions and direction, vessel loading, etc....., so you have to tab it by feel and GPS speeds to see where is most efficient.

Sometimes the most efficient tab setting is not the most comfortable for the passengers. If you are running into a head sea chop, sometimes you want to put the bow down a bit more to cut the waves better for a smoother ride. In a following sea condition, sometimes no tab is best for vessel comfort and handling. A little knowledge is a dangerous thing, sometimes the feel of the vessel is the best way to determine where the tabs should be set.

Safety Note: Entering an inlet with an onshore wind and outgoing tide can produce a large following-sea condition! First, this situation can be dangerous to enter even by the most experienced captain and should not be attempted unless you are sure you can handle it. Secondly this situation should only be attempted with the trim tabs all the way retracted (up - no trim tab). Trim in this situation can cause a dangerous bow steer causing the boat to be difficult if not impossible to control. Sorry to have to mention this, but sending a boat aground or up onto the rocks in this situation can be life threatening. Please be careful out there!

[AncientMariner]

Thanks ReelMagic and Chris.