BMS Stab Plate

[beradon]

I installed a BMS stab plate on my 115 Yamaha and the results are disappointing. At WOT the boat plows, even with 2 people sitting on the rear seats. It does get up on plane quicker and at lower RPM which I like but my top speed is 3-4 MPH less than without. My plan is to cut about 2 inches off of it and see what happens-Maybe I can reach a happy medium? I must say, its a beautiful piece of equipment, very well made and reasonably priced but it doesn't belong on a 190 Bay-

[Lazy Loafer]

I put a BMS plate on my 190 Bay w/ 115 Yamaha last year and initially thought that I would remove it because it seemed to cut down on my top speed, as well. Before you cut it up or remove it play around a little with the trim as you motor around. It makes the trim much more sensitive, small adjustments seem to make a big difference in the planing attitude as well as speed/rpm. In calm water, no wind, WOT my rig (with a T-top, 2 people, half a tank of fuel, and aluminum prop) runs at 39-40 mph (GPS)@5500 rpm, when I have the trim dialed in just right. What I like most, however, is the stern lift it creates that makes it possible to stay on plane at 17-18 mph.

[Putershark]

I agree 100%,
Trim is even more effective with this unit installed and since you are generating more stern lift, thus helping to take that job away from the prop (a job that many seem to forget that a prop also does) you may also need to swap out a few props (less pitch which equates to less drag at high speed) to get it all dial back in for max speed.

Before doing such though, use the trim button to kick out the engine once on a plane to get the bow (and the rest of the hull) pitched up. As the guy who got everybody started on this product here, I think you will find it very helpful and really help lower your fuel burn rates once you "re-learn" how to trim it again at all speeds, now that it is installed

[beradon]

I've tried everything to lift the bow of my 190 w/ T-top short of changing the prop. I've had it out about 1/2 dozen times under different circumstances, alone, with passengers, full tank/1/2 tank of fuel and at WOT she's plows-always. Obviously, if these worked on every boat, Yamaha and the other manufacturers would change the design of the lower unit. I agree that a different prop might life the bow but where do I get them? Do I just start buying new props and testing-hoping one will work? That would get kind of expensive and I could end up with 3 or 4 props that I have no use for. About 20 years ago I had a Scout that took forever to plane and I put a Doel-fin on it and worked great. Since then I thought that these things always improved performance but that doesn't seem to be the case. My boat went from a top speed of 39-40 (GPS) @ 6000 to 35-36 @ 5700. Its not rocket science to understand that if the bow isn't raised high enough, the increased drag is going to slow you down.

[Putershark]

I would check a few items then

• Let's make sure we are not dealing with a inner hull that is full of water and adding unneeded and unwanted weight. If so, easy enough to get it out by installing a drain to get it out and keep it out moving forward.
• As far as props go, I would install a Pro-Pulse model for testing (they have adjustable pitch) and as a good back up unit that will not rust. Also Mercury has a swap out program at some dealers that as long as you have not dented the prop, you can swap them out till you find out that works best for your set up. I am running a 3 bladed 17 pitch SS model, but my setup is not your typical "factory" at all...
• I would compare your present prop pitch and material to the ones that have been tested to work on the 190 hull by both Yamaha and Suzuki. Use that data as a base line to see how yours is working and the differences in both size and pitch as well as WOT readings.

Let us know how you make out

[cagrove]

Originally Posted by beradon

I've tried everything to lift the bow of my 190 w/ T-top short of changing the prop. I've had it out about 1/2 dozen times under different circumstances, alone, with passengers, full tank/1/2 tank of fuel and at WOT she's plows-always.

Not to beat a dead horse but...have you tried trimming the motor all the way down until you get on plane and then trimming it up until the bow rises? Keep trimming until you get that porpoising (up and down) of the bow and then back it down until it stops. The reason I ask is that I've never seen a boat that would run fine without a stabilizer plate and then not work with it. The stab plates usually only make things better and more responsive...not the other way around.

Just trying to find a solution.

[beradon]

There's no way that my 190 will porpoise-It never did with or without the stab plate. Like I said previously, if a bigger stabilizer would help all boats the outboard manufacturers would have redesigned their lower units long ago. Manufacturers of "stap plates" whether plastic or aluminum like BMS claim "most boats will run faster"-Not all. In this case, for whatever reason, mine doesn't. I will not change a perfectly pitched prop to make a BMS stab plate work. Honestly, it was a mistake to re-engineer Triumphs/Yamaha's design here and I'm not going to outthink myself. First I try reducing the size-It could work? if not, it comes off completely. Thanks for every ones suggestions. The sawzall is warming up

[cagrove]

Originally Posted by beradon

There's no way that my 190 will porpoise-It never did with or without the stab plate.

Then there is something else wrong...probably water in the hull. Before you cut up that plate I would advise you to address why the boat is not responding properly. Personally, I don't have a BMS plate, my Merc does a great job on my boat and I don't feel I would gain anything from it. I did have a boat that had a dolfin on it and it made a world of difference. Swapping props won't solve your problem if you have too much weight from water trapped in your boat. I guess what I'm trying to say is eventually you will have to address what's causing your boat to go plowing...but it's your boat and your plate. Let us know how you make out. Tight lines.

[beradon]

The first time i took it out after i installed the stab plate I saw the 3-4 mph loss of top speed and the plowing at WOT. I trimmed as much as possible and still couldn't get the bow up high enough. I am 99% sure the stab plate is slowing it down. It simply doesn't belong on my 190-its counterproductive.

[beradon]

I think my plowing problem is due to the stab plate because immediately after i installed it, it started BUT, your suggestion of water in the inner-hull has me wondering. How does it get in there? Won't it drain from the 2 existing drains ? Is there somewhere I should look for water?

My 190 was an 06 leftover i bought about 3 months ago. It only got about 50 hours on it-Is water in the inner hull common? What is the cure?

Thanks in advance