Typically, I set the tabs full down before getting on plane and then once I reach my desired cruise speed I retract them a little watching the speed. Each boat is different but often at slower cruise you will need close to full tabs, and as you accelerate retracting them result in a speed increase. This is pretty obvious in calm waters or light chops. As things get rougher, you have to experiment to find the best compromise between speed, efficiency and ride comfort. While you may gain a knot or save a few GPH by forcing the bow down, raising the bow may result in a smoother ride.
The conditions you site I wouldn't consider comfortable for cruising most 46' boats, however fishing is a completely different story. When I'm transporting those seas are nothing, but when I have an average owner and his family on board that's not for them. I used to run a newer 51 Bertram SF and those seas would be breaking things, in fact they hurt the owner, but I also ran an old 46 Bertram that would laugh at them. A lot depends on the boat and the purpose. Back on the subject of trim tabs, I probably wouldn't be using any or much tab in those seas except to lean into the seas when running side to the them. I probably would as I'm running the inlet and bay.
I spent much time and money and installed Bennett's latest tab control(EIC5000), it's a great control. After I used the boat I then realized the boats hull is a big trim tab. I almost never use the tabs, usually I only use the tabs to straighten a list, when I have an uneven boat.
Check the boat's speed on a calm day using different tab settings as suggested before. Most boat's like to run with some tab. Bow up is seldom the most efficient running angle for a boat of any size.
Finally that's my conclusion too Ruby! Ok, if in a calm sea (we have that tomorrow) I probably can put the bow down an gain some speed and still have a dry ride, but most of the time we have 4-7ft sea, so bow up is a more dry ride and gives more comfort, and that’s what we like! FYI, I never fish…
After reading this thread, I had it in my mind to try this out when we were running down in FL last week. On average, we were seeing 2-4' seas, with periods around 4-7 seconds. Obviously thats an estimation and average over the course of the trip. But, that being said, on average, irregardless of sea state and direction, I was seeing an uptick of ~2-2.5 kts when we used the tabs. My boat has the 3406e package, and at 1950 rpms, I was seeing 26-28 kts. based on the tides and currents with the tabs deployed. Im pretty satisfied with the bump that they provide, seeing as how you maintain the same fuel burn with the added speed.
Pt Judith, I don't know if I would trust a guy who says he has the tabs dialed in on his new boat; but can't figure out how to use a washing machine. LOL..
Evidently you don't know enough male boaters. Some of us have mental blocks about certain things. Sort of like the one my wife has against our lawn tractor and power tools.
Ouch! Touchet... I'll give you that one. However, I did run the boat straight for the better part of 50 hrs over a 6 day period. I just didn't have the need to do a load of whites!! haha.
For most guys, that's why they have a wife. They would be able to even feed themselves without one let alone survive! LOLOLOL
Back to the trim tab topic and interesting informations mentionned above, my '82 44 ft Lace has no trim tabs. I saw others Laces, certainly a bit younger, having some... So immediatly, the questions that come to my mind are - why next Lace were built with Trim tabs? - are they needed for a Lace? I do not intend to use the boat in rough conditions and even don't know if she is capable of going out by rough conditions. Any inputs to help clearing my thoughts are welcome Thanks
It depends on the hull and weight distribution as well as where the tanks are located. Some boats really trim tabs to get on planes, others very little. I recently increased the trim tab size on my 53 Hatteras during the repower it really helps reduce bow rise while getting on plane. I ve been running an 84 Lazzara for the last 2 1/2 years and the boat has no trim tabs but a thin stainless strip against the transom, where the tabs would be, extending about 1/4” This is enough to create the lift needed to get boat on plane with close to no bow rise. If your boat gets up on plane at a fairly low speed 15/16 ktsbwith minimal bow rise you don’t need them. If it struggles bow high then trim tabs would help
How does the boat ride at cruise? Does it run bow high? Does it take a while to get on plane. Generally on most all planning hulls and semi-displacement hulls, trim tabs can consistently increase speed and efficiency 5-10% at cruise speed/on plane, that also extends to in calm water.
The sea trial we did went well. I had the feeling that she planned very rapidly, maybe 11-12 knots, which I think is a characteristic of the Lace. Cannot really say about the bow, was to focus on how she was doing. I think I will keep collecting inputs and datas, will run more tests next season and eventually equipped her with trim if needed. I wanted to post a video of the sea trial to get your inputs of the level of wake she creates but I have not been able to load it. Don't know whatvI'm doing wrong here.
You have to load it somewhere else, like a hosting site or youtube and then post the link here. I'm not familiar with the Midnight Lace's but most planing boats benefit from trim tabs.
The Tom Fexas designed early Midnight Lace boats were inspired by his childhood and family experiences with Elco boats. These predate the breakthrough Hunt designed Bertram 31 planing hull. They are not true hard chined planing boats, more like soft-chined semi-displacement hulls meant to be easily powered to run through the waves instead of totally on top of them. Hence the lack of need of trim tabs.
Agree with Capt J If it rides stern down bow up it would benefit from trim tabs depending on cruise speed.