TomZ

iTrader: (2)

I can pull a pair off the Cigarette (26P stock Bravos) and give them a try. I keep hearing that a 4-blade isn't necessary with the deep drive TRS. Bravos really like the 4-blade, but not the TRS. Like I said, that's what I keep hearing. Is that accurate?

RGPIII

Thats very possible. I don't have much experience with the TRS drives.

ph1971

iTrader: (1)

I can tell you that a friend of mine with a 38 Bertram and TRS behind 420's went to Bravos and picked up performance from hole shot to top end and the economy difference was significant. Not sure how that translates to your 311 but he has nothing but praise for the four blades. I would get those 26's and take a spin.

TomZ

iTrader: (2)

If I can get out to the marina tomorrow, I'll swap props and see what happens.

I got out to the boat today to fix the GPS speedo, and install my new GPS. While the boat was on the work rack, I broke out the straight edge to see what was what.

For the most part the hull is straight/flat for the first dory and a half feet. From the four and a half foot mark on, the hull starts to taper away from the straigh edge. This is where the rocker comes into play I'm guessing. I didn't go beyond what I saw in the first four and a half feet. I'm thinking this is not outside of spec. .

I also checked the toe... the drives are pointing inward about a quarter inch. I was going to attempt an adjustment, but the tie bar doesn't use a true heim joint. I'd have to take more apart to make a change. I'll wait for now... one thing at a time.

Audiofn

I go toe in slightly but only slightly. I don't think it matters much toe in VS toe out. With the nose cones you do not want strait especially if you are running stock steering. If you are strait the drives will want to dart or vibrate. I would check about 4-5 feet up the boat with your edge for hook rocker, and also don't forget to look at your strakes. IMO I would not run 4 blades on a TRS boat. 1st they are way to deep, second the drive will be much more likely to fail.

ph1971

iTrader: (1)

Sick Stinger has a pair of 26's for $600 in the Swap Shop.

TomZ

iTrader: (2)

They're tempting, but my worry with the 4-blades is the increased loading on the lower units of the TRS. I've got a set to try, but I don't want to hurt anything. Where I live and run the boat, rough water is frequently a possibility. The last thing I want to do is blow a drive!

Audiofn

You should be fine to try the 4 blades just for a test just don't over trim them and keep them in the water or be careful throttling....

Paul311

From my experience, the Bravo 1 props will give you a very different ride compared to the Mirages. last week I have been testing a set of Mirage 23P , 25P both plus, and Bravo 26P on a 311 with bravo drives.

The behaviour of the boat with respect to porpoising is way different with the bravo's, in other words, porpoising is not happening at all. Even at very low speeds. While the bravo's are lifting the stern a lot more compared to the Mirages, getting on plane is so much better. They keep the bow down. Cruising is possible at almost any speed from 30mph up, that is not possible with the Mirages.

With the Mirage Plus I have experienced the same issues as you Tom, although a little less as you described. I might be the bravo drives, or the Mirage Plus. Cruising below 3600rpm the boat is very sensitive to porpoising like you say. I don't use the taps either, only the drive trim.

Cruising 3200-3400 I am at 3-4 drive trim to keep her steady. Not sure at what number the cavitation plates are on the same plane as the hull bottom. Sometimes, porpoising is starting to occur, I trim the drives a little in, it stops, and than slowly out again. To stop porpoising with the taps, you need a lot of tap so I prefer to use the drives. Cruising @ 3800 (if that is still cruising) I have no issue at all. I am not sure about the speed, depending on the 25P or 23P, I am around 55-57mph if not mistaken.

With the Mirage props I feel that I am continuously willing to give a little more throttle unit I am in the 3800 range because that gives the best ride, independent on wave conditions.

When slowing her a little down, you need work with drive trim to prevent porpoising and provide a stable ride.

This is far different with the bravo's, getting on plane is so much better, I didn't notice any porpoising at all. I just trim the drives until there is no speed gain anymore trim them a tad back in and leave it there. Bravo's seems the best choice, although not for top speed. The 311 requires some bow lift to get it to 70mph and that is exactly what the bravo's do not provide. They keep the bow down, bow steering occurs and it is getting a little scary so to say. You need to trim the drives of the scale to get anything close to top speed they will blow definitely. Not the ideal combination for top speed. In that case the Mirage plus is the far better selection.

TomZ

iTrader: (2)

Great write-up Paul.

I tried a set of 26P Bravos and they were not much different than the 27P Mirages. The attitude getting on plane was a little lower, but not much difference in handling or time to plane. Porpoising changed a little, but not enough to warrant a change to 4-blades.

I have a stock set of 25P Mirages on her now, and she's pretty livable. Something in a 25P 3-blade seems to be the sweet spot. I can still maintain plane at 26-2700 with the ones on there now, and the top-end is good.

I'm going to grab Jon's (Audiofn) 25P Mirage Pluses in the next week or so to give them a try.