TOPIC: Nauticus Smart Tabs

Yo Jerf. Taking your motor height into consideration y'oughta try a 'chopper' vs a cleaver on that thing. Jmo ...

I think this is a very interesting thread as most all the reasons why hulls porpoise are mentioned, and most are discussed: how true the hull is; weight distribution; gearcase/midsection drag; and the inability of the propeller design to carry the bow.
Ron, as I and others have mentioned, I strongly feel that gearcase/midsection drag is the root cause, and therefore the motor should be raised. As I also have mentioned, you do not have to buy a $500 prop to stop the ventilating. At worst, a performance 4-blade aluminum propeller @ $165 would work. It is also possible that a still lower cost aluminum could work well.
Frank, your situation is a little more of a puzzle, but as Randy stated your props cannot carry the bow. I would recommend the $165 performance aluminum to you also, but do try first Dave's Laser II to see the results. You may also benefit from raising the motor some more to reduce gearcase drag (as another person previously mentioned). If you have not done so already, trim the outboard precisely such as the bottom of the ventilation plate is parallel with the hull, and carefully double-check the raised height to ensure that it is 1" you state that it is (is it possible that you are actually somewhat lower or higher?). Another thought is that you likely could benefit without the speed loss with some "U" shaped tunnel extensions (as your hull's tunnels are upside down "U"s). These would also act like trim tabs, but not limit the amount of bow lift.
Chris, I do not remember ever reading your advice and not thinking well of it. I do however strongly like vented props. I do hear good things about the Ballastic (we can competitively sale these also), but they are very similar in cost to a Lightspeed, but without the factory vent holes.

Regards,
Joe Poole, Jr.
www.fergusonpoolemarine.com

Ron & Joe,

You can get a 4 blade aluminum prop for less than a hundred bucks (including shipping) here: boatpropellers.iboats.com/Mercury/90_-_150_HP_%28Thru1977%29_21.00-Pitch_Propellers/294/?rotation=Standard&session_id=900247069&cart_id=168943128

We went out on the Hudson again last night for a spin with my mid-80's mother-in-law. Man o man, she's a great powerboater! Gail was sitting in the back on my new bench seat taking this video. She says the bench I built is great.

Worked great going upstream, crummy going down. Maybe fighting tide? No clue. Man, I wish there was a lake close by I could test this boat on that didn't have current and tide!

Frank

Frank I suspect the tide was going out, which gave you more speed going up river than down. Just take the average of the two readings and you'll have a good speed estimate. If you want a fun day not too far away, haul it Cooperstown and do the lake there. It's pretty and you can tie off a couple of spots for dinner.

This is some good readin'! Thanx!

This is some good readin'! Thanx!

Isn't it amazing how much more enjoyable and informative this is when everybody stays "civil"!!!
I agree wholeheartedly.

This is from this morning, a beautiful sunny, calm day, just a bit of chop, on the Hudson River south of Albany. Actually my son Gregg and I ran WOT up to the City of Albany and then down to the Castelton-on-Hudson bridge of the Mass 'pike extension on less than 6 gallons of gas. That's more than an hour of running, mostly at WOT. Handles chop well, and we did all the wakes we met at WOT, did great, lots of fun. Only hit 30 though, did better yesterday with more weight in the back of the boat. Motor is hummin right along, tach is reading 5000-5300, so far so good. Not as fast as I had expected, but a bunch of fun!

This is with my series 40 Smart Tabs SX set for the most pressure. I may get the series 60 gas actuators and switch, see what happens.

I had Gregg take this video of the 'Cat running from the dock we launch from (Henry Hudson Park, town of Bethlehem).

Whadya guys think?

Frank

joe, i can't disagree with anything you say. your advice is well taken. my hesitancy to alter the boat or motor in any way is because the first 2 years i ran the boat (2006,07) it did not porpoise.i'm hoping the sand bags will make a difference. ron

crosbyboat wrote:

Frank I suspect the tide was going out, which gave you more speed going up river than down. Just take the average of the two readings and you'll have a good speed estimate. If you want a fun day not too far away, haul it Cooperstown and do the lake there. It's pretty and you can tie off a couple of spots for dinner.

Where do you launch there B? No state launches. F

Hi Frank,
First let me state that I have no illusions that I will do business with you, but buying a 4-blade version of the same propeller you now have (that cannot carry the bow) will not solve anything. Yes, I too sell these propellers for a much lower price. The Laser II, Lightspeed, Chopper, Ballastic, Turbo (to a lesser degree) propellers previously pictured have a much greater rake angle with performance profile blade designs (the older stainless 2-blade you tried also had little rake). I do not know the effect this has on manufacturing costs, but the reality is that all the manufacturers charge a significantly higher price for these style props. Many boats do not need this technology, however you have one of the most respected performance boats of the past. As I have read somewhere else, "you do not want to put 6.00 X 15 tires on a Corvette". Going with this quip, if you did you would have handling problems, and likely the ride would suffer. I think that this is a big part of where you are at (this is basically the advice Randy gave you). I am also concerned that stronger actuators will only hold the bow down more. A porpoising boat is no fun, and it will be interesting to see what solutions are needed to get your rig "dialed-in". I am sure that there are others that can better address your issues than I, but I do have a lot of experience, and I feel that my father was one of the best. You may get a smile from some of the pictures we were able to post to the "About Us" section of our website: www.fergusonpoolemarine.com

Regards,
Joe Poole, Jr.

Joe, what prop were you talking about for 165? Even though that may be reasonably priced, it's out of my range right now. Guys on the Power Cat email list are suggesting that I'm not turning enough rpms and need to go to a 19 or even 17 to get up towards of 6 grand. They also suggest that I need to somehow drive through the porpoising. So while it's tough to do, guess I'll have to drag the boat out to the river again today and play some more...

Frank

frank, i have a 17 pitch 2 blade lummie and a 3 blade 15 lummie.

71 V153 wrote:

Yo Jerf. Taking your motor height into consideration y'oughta try a 'chopper' vs a cleaver on that thing. Jmo ...

See, now i keep getting conflicting info...some say chopper, some say cleaver, some say screw both.

I need to just find someone whos got a whole bunch of props for this thing and sweet talk them into letting me try them all!

vuyosevich wrote:

frank, i have a 17 pitch 2 blade lummie and a 3 blade 15 lummie.

Thanks Ron, but I've found 2 blade props don't work good with this set-up for some reason. 15 pitch is I think a bit too low a pitch.

Frank

JerrfyLube wrote:

71 V153 wrote:

Yo Jerf. Taking your motor height into consideration y'oughta try a 'chopper' vs a cleaver on that thing. Jmo ...

See, now i keep getting conflicting info...some say chopper, some say cleaver, some say screw both.

I need to just find someone whos got a whole bunch of props for this thing and sweet talk them into letting me try them all!

Jer- Look at the Stiletto on p.2 of this thread. A similar prop in 22" pitch would be the first I'd try. If you can find a dealer who will let you try a few if you guarantee a purchase, that would be excellent. (some call them bass boat props, they are bow lifters)

PC1000 wrote:

vuyosevich wrote:

frank, i have a 17 pitch 2 blade lummie and a 3 blade 15 lummie.

Thanks Ron, but I've found 2 blade props don't work good with this set-up for some reason. 15 pitch is I think a bit too low a pitch.

Frank

I agree, Frank. At least with pleasure boats. That's why no modern manufacturer offers a 2 blade for anything but racing boats. And many race boats even run 3 blades nowadays.

F - There are 2 launches in Cooperstown on Otsego Lake. One is a town launch ramp that you pay a launch fee, the other is a state launch ramp and there is no fee. The town ramp provides a deep water launch. The State launch is a shallower launch. They are right next to each other, and very close to the Otesago Hotel. It's a really pretty lake with a lot of history. No more than an hour and a half from our place. B

After running 3 blade 19 and 22 on the Manta Ray I ran the 2 blade I let Frank try. This was sent to me by Gary MacNorius in FL because he thought I could get more out of the Manta Ray. Hands down the 2 blade stainless cupped prop ran the best. Close to 60 mph with the 1350.

Hi All,
I had the camera out taking pictures to add additional items to our website, so I thought a few pictures would help me better explain what others and myself are trying to explain. The first two pictures show a 24" pitch Laser II on the left and a 23" pitch factory cupped aluminum 3-blade approximately 1972-76 vintage. Using a tape measure and eyeing it, there is a 1.5" difference in the blade length due to the greater rake and blade profile of the Laser II. This is what carries the bow.

Well, that was the first time I remember adding a picture since the new site came on, so obviously I only posted one picture. For the next picture, I had a '60's 23" pitch Mercury bronze 2-blade propeller out to take pictures of anyways so I decide to compare it as well (this should the same as the 2-blades that you have Frank, and would very similar to the correct props for Ron's 1962 Merc 700 FGS). As hopefully can be seen, the bronze 23" has even less than the '70's vintage aluminum 3-blade. Jer's 3-blade bronze would similar to either the 2-blade or 3-blade depending on it's true vintage.

The next picture is of a 1962 Merc 700 FGS driveshaft housing (also referred to as the mid-section or tower) without the gear housing (also referred to as lower unit or foot) installed. This section would create a tremendous amount of drag if in the water stream exiting the boat's transom. This does make every planing hull boat with a motor thus mounted porpoise that I can remember. Frank's Merc 1000 would have the same part number driveshaft housing as the one pictured.

Ok, after being in an IM with ron tonight he kind of directed me towards this...of course go figure all I am going to do is apply basic logic like I did with ron about his porpoising.

First, with rons he told me he wanted to put the extra weight in the bow, and when I got thinking about his boat, logically speaking the better place to add weight to his boat would be the stern. I run around 215 pounds and I reminded ron, this last time at silver I rode in the back and the boat didn't porpoise, nor did it in the first race between him and CC when he had bob beers son with him, the 2ed one he ran alone and he porpoised badly. so weight is definitely an issue with rons boat.

now with a normal hull if your porpoising you would start front of the center point with something, anything...rearranging the helm configuration, sitting location anything to shift the weight around but in this case that one thing that can't be done. so if you have a standard boat and you have the same issues you would add weight forward of center but not forward of the center point of plane, and work that back or forward till you solved the issue, rons boat is a little bit more complicated, so isn't franks.

both are the "basic boat" as to having a "three point planing hull", but not in the same manner as normal "V" hull where they have a somewhat hard to understand technological lift principal much like an airplane, take away the the lift, the bow goes down and it tries to reestablish where the helm reacts by pulling the power and next thing you know, the bow is bouncing like a kids toy sometimes often enough to the point of becoming shoveled.

now with a planning hull that use air as a matter of lift, like my Thunderbird did, ron does and all so franks, the big thing would be to add weight to the stern, this would of course sound like the logic would bury the stern but what the reasoning behind it is, is to cause (a force) weight over the exhaust area for the intake from the bow, that would prevent a blowout of the trapped air that by design is lifting the stern to begin which ...pushes down the bow which after the boat get into this "configuration", it is riding on a bed of air that is intake through the front and by design because of the step hull design that then traps the air from escaping and then exhaust it out the back in a forever narrowing chamber, like rons and franks boats are designed.

Now for props, brass or aluminum, cupped or not or....a chop prop, which if I remember right, a chop prop had only one blade....a really simple way to find your pitch is simply use a three bladed variable pitch plastic prop to find your sweet spot, and then invest in the more costly prop or try one out at your local boat shop or dealer. still the variable pitch prop has it advantages, a blade if it strikes something will brake off where your able to either take a dip with an allen wrench and add a new blade, or limp back to a doc and repair it and go about your fun for the day. Where with a metal, more expensive one if you ding um...your done till you can afford to have them repaired if they are repairable.

all off the above, is a matter of my own opinion, which if you ever hear a babbling coming from a nearby brooke...

For the final picture, I shot a picture of a 1963 Merc 1000 gear housing assembly (Ron's 1962 Merc 700 FGS gear housing is very similar if original). I wish to point out that there is a section of the gear housing case between the driveshaft housing mounting flange and the bottom of the ventilation plate which is less blunt, but often still causes porpoising if in the stream exiting the transom. Some believe that if the outboard is mounted such that the bottom of the ventilation plate is flush with the hull bottom that the described area is not in the stream. However, the water is trying to fill the hole made by the boat, and the water travels upwards at an angle, thus striking this area. I personally have rigged a performance boat (that we had previously sold others before of) with a new design motor recently introduced, mounting the motor elevated above this flush point by a noticeable amount (I do not remember exactly, but I will guess 1/2"), and when tested found a bad porpoise. On larger Mercury models starting in 1984 & '85, there are 5 sets of holes one can select from without redrilling new holes. These change the height by 3/4" per hole. By just raising this particular outboard one more hole up, the porpoise 100 percent completely disappeared.
Frank, I think that you need to try a high rake prop, but I am concerned that you may have to raise your motor, and possibly shift the weight to get to where you need to be. Going to saddle tanks would be ideal, but the engine height and propeller should be tested first, as moving the fuel tanks may prove unnecessary. Unfortunately, with the motor trimmed under and the smart tabs, it is impossible to know your motor's true RPMs to determine the pitch needed. Dave has offered the use of his 20" pitch, and it should be close enough at worst to determine what your true RPMs are after solving why the start tabs are needed.

Frank evidence of what Joe Poole is explaining can be seen in your video named "my video 14".....see frames 15, 16 & 17 the water is hitting the fin shooting upwards and dragging on your boat I had the same issue on a tunnel boat
raise your motor I bet you gain 5 mph or better, then you can worry about props if necessary

Hi Houston,
I have no problem with your thinking. My point is simply that having to place ballast anywhere to stop a porpoise problem is a waste of fuel, and likely space and convenience inside the boat. The transom of Ron's boat was originally set to mount the motor's ventilation plate at/above the tunnel's floor (bottom). This was altered due to propeller slip. In the early '60's, it was very expensive (relatively) to purchase a propeller that would have solved the reason for cutting the transom. This is not the case today. Why not let the boat & motor perform as they were designed to? There is no longer a propeller obstacle requiring a bandage like ballast or smart tabs.

MadProps wrote:

Frank evidence of what Joe Poole is explaining can be seen in your video named "my video 14".....see frames 15, 16 & 17 the water is hitting the fin shooting upwards and dragging on your boat I had the same issue on a tunnel boat
raise your motor I bet you gain 5 mph or better, then you can worry about props if necessary

Here's a pic of my motor in a vertical position showing the cavitation plate above the bottom of the hull. That's Brian Lawson taking a look and from what I remember giving it his "stamp of approval."

How far up should I go Michael? An inch? Two? At some point I might run into the cross-brace that supports my custom splash pan. I'll have to take a look. I could take another pic later today maybe if this one isn't sufficient. Moving the motor up is at least affordable, but then I have two 3/8 bolt holes to fill!

Frank

Frank,
I may have missed this somewhere, but are you checking the speed by a speedo or a GPS? Also, the motor doesn't really sound wound up to me.

GPS Doug. Yeah, that's what everybody says, but I believe my tach is accurate. Getting a Teleflex outboard tach this week, we'll see if there's any difference. Should be here Wednesday. Plus a buddy is sending me a 17 pitch 3 blade prop to try. Guess I'll take those two 50# bags of sand out of the back, no question the extra weight hampered performance. I only tried that late yesterday, the videos here did not have that weight in the back.

All I want is to get this baby on plane. Sheeesh!

Frank

Frank
when I ran into this issue I had to raise my motor 1 " above the sponsons, each hull is unique to dial it in

I use whats called rev sticks to find my optimum height
1/4 thick wood strips placed under the clamps, and I jack up the motor 1/4 inch at a time, till I start to loose water pressure then I drop it back down a 1/4

this may take care of the porpoising, you will gain speed, & then you can dial in a prop

And you can tell when you lose water pressure by keeping an eye on the pee tube when you're testing it right?

I have to take a look at where I mounted the holes to see what I have for wiggle room.

Thanks Michael.

Frank

yes Frank watch the tell tale,

Now keep in mind this is a starting point you may find that due to a loaded boat ,water pressure loss from turning, triming etc you may need to drop it another 1/4 to maintain good water flow(if you have a water pressure gauge watch it closely when first testing), but this method will definitely get you up to optimum height

Ok to help clarify what I was trying to say while I sit in front of my fan, if the on plane diagram (two points on the stern and one just aft of the bow on the keel) on a normal boat, the "lift principle" of the air intake under the bow is not taken into consideration with a manta-rays Cat Hull.

I use whats called rev sticks to find my optimum height
1/4 thick wood strips placed under the clamps, and I jack up the motor 1/4 inch at a time, till I start to loose water pressure then I drop it back down a 1/4

now, i have been suggesting this to ron for...a..while..now.

more babbling....

Ferguson_Poole wrote:

Hi Houston,
I have no problem with your thinking. My point is simply that having to place ballast anywhere to stop a porpoise problem is a waste of fuel, and likely space and convenience inside the boat. The transom of Ron's boat was originally set to mount the motor's ventilation plate at/above the tunnel's floor (bottom). This was altered due to propeller slip. In the early '60's, it was very expensive (relatively) to purchase a propeller that would have solved the reason for cutting the transom. This is not the case today. Why not let the boat & motor perform as they were designed to? There is no longer a propeller obstacle requiring a bandage like ballast or smart tabs.

No problems Poole, Never ever with me.

The one other thing that is really overlooked from everything from back then to now days is how "stuff" was made, back then gas tanks where made out of heavy metal, now days they are made out of plastic which would subtract from the over all weight that would be "gear" inside the boat.

I have an old metal tank in my Garage and a plastic, both are empty but the metal one feels like the plastic one does when it is full, back in the day add the fuel weight to the metal can.....and in the stern you would have more weight.

frank, i hope i'm not hijacking your post but its the same problem.
mark,i refuse to drill new holes in the transom. if someone could do it (i'll pay of course) and guarantee that it would solve the problem, i'm all for it.
joe, i understand the drag principle. thats why i'm getting a waterfall into the splashwell at wot.
frank, did the sand make ANY difference, and did you try putting the bags in the front?

these are some ideas i've received but all mean having to drill new holes an inch or so higher and then i'm into a transom crossbrace which looks like a 2x4. the holes cannot be drilled from the inside either.

Frank- Looking at the pic above, you can raise up to 2" before beginning to "uncover" your water intakes- remember, water coming off the transom angles upward. You shouldn't need that much, but can rest assured you have a margin of safety for water pressure. I hate to mention anything that costs serious money, but if drilling more holes is taboo, what about a manual transom jack that uses a ratchet to raise/lower the motor in small increments? Lets you do a lot of testing without pulling the boat out of the water every time.

Bass Pro Shops website shows a CMC (quality MFR) manual jackplate for $250. Adjusts on the boat with wrench or ratchet.

vuyosevich

yes you have the same problem,I can see yours is probably more severe than Franks, just jack your motor, dont drill new holes till you are satisfied your at the correct height, safety chain the motor down is what I do while testing for my height..... then final bolting to the transom

now if you have a motor without clamps or the cash you can as Kerry posted buy a jackplate

I immediately recognized the problem when I saw Franks video at the frames where hes driving away, 2 weeks each summer I remove the race motors & put fishin motors on my hydros so all the kids & guests can play with the boats at safe speeds on the river when they visit for vacation

I ran into issues both ways race motors on standard transoms and long and short shaft motors on super short hydro transoms I was puzzled like you guys are but took videos of the water spraying upwards made some rev sticks and picked up 8mph.
the short racing transom made my issue way more severe and easier to diagnose than Franks and had to weld up a jackplate to go high enough

Kerry wrote:

Frank- Looking at the pic above, you can raise up to 2" before beginning to "uncover" your water intakes- remember, water coming off the transom angles upward. You shouldn't need that much, but can rest assured you have a margin of safety for water pressure. I hate to mention anything that costs serious money, but if drilling more holes is taboo, what about a manual transom jack that uses a ratchet to raise/lower the motor in small increments? Lets you do a lot of testing without pulling the boat out of the water every time.

Drilling more holes for me is NOT taboo. Just so ya know. But with the heat index over 100 today I ain't even goin out to look! Call me a pussy, but that's the deal. Supposed to be brutal till Friday or so.

Frank

frank, i was outside all day.....IN THE POOL,water 85degrees.your welcome to come down.

the more i think of houston's reasoning...the more i like it. maybe because it only cost me 6 bucks for sand.lolol