PROPosing another Prop question...

[Craig]

fnshrmaster,

A Baja Outlaw is not a faster hull than any 25' Convincor. Sorry it just isn't, old models or new. I could go on and on giving you examples of both the older models and newer models running faster and handling better than a Baja the same size and with same power.

They are just harder to prop than other boats. That's all. The Outlaw hull design is NOT superior. The Convincor is 5-6 mph faster with same power.

Sorry buds, you have to "Drive" a Checkmate.

-Craig

 

[the sMac]

I wanted to post a follow-up to my PROP search.

I mounted that new Revolution 4, 21 pitch for the Poker Run. My results are: FAIR.

I am loosing 2 MPH of my old and tired 21 cleaver. I am only pushing the boat to 51 MPH (GPS) at 4500 rpm.

I could try to get a 19" pitch and gain those RPMs, but I don't know if it will matter now. I like the cruising speed a lot, the hole shot is much better and it handles a little 'higher' to me. It just feels different.

I also could plane at lower speeds and my cruising speed is up a little higher.

BUT, the porpoise issue.... I thought it went away until I filled the fuel tank up. Then it came back, worse then ever!! Damn that hull.

MY QUESTION NOW IS: if I am turning a 21" pitch at 4500rpm, and at 51MPH WOT, what will happen with a 19" pitch? Faster top end, slower top end, etc?

ugh, the journey continues.

 

[Craig]

Isn’t the Rev 4 more for smaller boats, and less hp?... Not familiar with it. Like I mentioned before, you need something that will hold the bow. I think a bravo will do the best. When Mike advised a Mirage he was probably just trying to get you top end.

This hull is not the easiest to prop. On my 270 (old 259) I have run Mirages, Bravos, and Hydros. All of these work well for different types of running. I like the Bravo the best. With the Bravo on, I won’t porpoise until I get under 3200-3400. I had the Hydro on yesterday, it will porpoise when rpms fall under 3600-3800. Don’t remember what the Mirage does, just know I like it the least. Great top end, but that’s where it stops, bad hole shot, and bad midrange.

These hulls will act different with different loads and water conditions. They can be a challenge to figure out. You will get it though, be patient. Use your tabs, play with your trim. It takes a little more “driving” then other hulls. That’s all. But sure, an Outlaw is going to be easier to drive. Thing is, do you want a slower boat that weighs as much as a milk truck and sticks to the water? Some do, that’s fine. Not me.

-Craig

 

[the sMac]

HEY, stop. I never said I wanted a Baja (did I?)

Craig, thanks for the advice. I was told, a few times, that I couldn't turn a Bravo One prop. It starts at 22pitch. Too much for me.

That's why I was pointed into a Revolution 4. Hydromotive said they had a good prop for me, but they weren't going to make it until next year.

I would like to try a Bravo One, 22" and a Revolution 4, 19". But it's not easy finding a prop to try and I can't afford to keep buying $500 props.

I think the REV4 is for "lesser HP" boats. But, sadly, I think that's what I have. I'm only using a stock, 454 MPI. 310 HP I think. Maybe I need to boost the HP a little??

Thanks again... I don't want a Baja!!

 

[mkhammer]

sMac I tried to tell you The bravo1 is for your boat.I see revelution props on 18' boats If the 22 pitcth is to much you can have it worked to gain your rpm back. it will take away some of the porpoise track better, turn better, cruise better, less slippage = more mph at lower rpm. I have a 253 convicor I spent alot of time and money to get my boat the way I wanted. I run a 30" bravo prop. I have 24" billet trim tabs and I can adjust the porpoise out of my boat at any speed.

M.K.

 

[the sMac]

all right. I will try to get my hands on a 22" Bravo One and test it out.

I got scared of that prop when everyone told me it was too much fore me: Mike at Checkmate, Hydromotive, Leon Derebery, and Julie from that prop place in Florida.

I don't know where I can get one, but I'll try it and see what happens.

That is the reason everyone suggested the Revolution 4. They thought I could turn it without a problem.

thanks again

 

[Big Dave]

Just curious, you keep saying L79 454.
Is that a replacement engine (aka Targetmaster?)
Did you replace the cam w/ marine?
truck cam's work horrible in boats and will kill your power.

 

[the sMac]

Big Dave.

Wow, you just got home from that long haul and you're already posting. neat!

It's a L29, 7.4 liter (454) Mercruiser MPI engine. i say L29, because it's a different engine then a 454 Mag, a 454 EFi, and so on.

When I look in the books for plugs, serpentine belt, or anything, the 7.4 liter L29 seems to have it's own listing.

It is a Mercruiser engine though. A 2001 model. I didn't do a thing to it - it's stock.

 

[mkhammer]

sMac
Another thing if you don't know your trs drive has more drag than a bravo 1 and I beleave you said it runs deep in the water. X demension has a lot to do with your boats performance too deep and it kills it. A 454 mag mpi is rated at 385 hp. some of the lower hp 454 were rated to run at 4600rpm. So I'm not sure what you have. go to stem to stern .com they have complete ID # ,year and engine listings you may be able to find your engine rating there. The cleaver you have is usually is ran on high preformance outboards or surface piercing drives. before you spend any more money there are companies that have a prop exchange policy. selecting the right prop can be hard somtimes. see if some has a 22 bravo1 you can try if that is too far off no sense in having it reworked the next thing you might consider ie a 21 or 23 mirage 3 blade.

M.K.

 

[Craig]

sMac,
My Outlaw comments were for fnshrmaster. I think he should buy one. They're "the bomb". They are so much better than the 25' Checkmates...lighter, better bottom, faster... I might sell my 270 and get one.

-Craig

 

[the sMac]

mkhammer:
Thanks again. I don't have a mag. I have a L29, I thinks it's a 310HP engine. So, take that and a TRS with a transmission and you're probably talking about 280HP!! hahaha. I might not be far off. Plus, I also went from a 4" exhaust to the original 3" holes in the transom. I don't know how much power loss that equates to, but it's gotta me something. I think I need to put on 4" thru-hulls next year.

I will try a Bravo One 22 when I can get my hands on one. Mike at Checkmate said a 21 Mirage Plus, but everyone else said that prop is no good for me.

Yes, try and try again. I am pretty satisfied with the Rev 4, I like the ride and mid-range speed. I just can't grasp the reality that this boat will only go 51 mph now.

Craig:
Okay, that makes sense now. I thought that Baja comment was meant to me. If you knew me, you would know I am a Bayliner fan!

 

[Ruus G.]

I have a 240 Baja and a 25 Conincor. You can drive my Convincor if you want because its for sale. Why should you have to work so hard to get a boat to stop boncing down the river. The boat handles great except the porosing. I fully customized my Checkmate from top to bottom. Paint,engine,intorior,etc. I even added large Eddie Marine trim tabs. Believe me I spent alot for time and money and dont want to give up on this boat but its embarassing bouncing down the river. I dont think the Baja is a step up though. It has its problems also. But it does not Porpose!! I think its time for a 28 Pantera.

Russ

 

[Ruus G.]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">mkhammer </div></BLOCKQUOTE> What are the tricks with the taps and trim??? I also have 23 billet tabs. How much to you have to slow the boat down with the bow in the water to get the porpsing to stop?? Please save me from selling my boat. I'm looking for honest replies about this haul design. I know we are proud of our rides but is this a defect in the 25 convincor design?

Russ

 

[the sMac]

I took the boat over to Cedar Point last night... great nigh. Calm, warm and a full moon was out.

Anyway, I filled up the fuel tank - to the top - never do that usually. It was almost funny how badly it bounced after that!! My wife was getting wip-lash going anywhere between 25-45 MPH.

I had to trim the engine way down and put the tabs all the way down - and go about 30 in order to stop it. OUCH, it was terrible.

Now I remember why I never filled it up al the way.

 

[Craig]

Russ G.
It’s not a defect in the hull. There are a lot more difficult hulls to drive out there than the 25’ Convincor, but it is a little more of a driver’s boat than some. My opinion is most of your better performing hulls are going to need to be “driven”. I’m so use to driving fast outboards, that I get in my 270 and can’t get over how easy it is. But I do have good seat time in 25’ers also – Baja’s and Checkmates. I can get behind the wheel of an Outlaw or 272/275 and just about fall asleep. If I let a Baja guy drive my 270, he doesn’t have clue.

Guys, We’ve all seen 25’ Checkmates bounce around like basketballs, fine. But, we’ve all seen them run smooth as silk, also. If you want a boat that “sticks” to the water, then you probably don’t want a Checkmate.

I would call Mike Combs and ask him for tips, but I can give you some:

First make sure it’s propped right. Some good choices are mentioned in this thread: Bravos, Hydro4’s, Mirages….Now, get a feel for what the boat is trying to do. Use the drive trim. Use the tabs. Try different combos of the two. Maybe slight trim with tabs down 4 deg, maybe heavy trim with tabs down 6 deg. Depends on the load, water, prop, and speed your going. I personally hate messing with tabs. Talk to some of the “old school” 25’ Checkmate guys. Many of them will say “what are tabs” Sometimes you just have to keep the boat guessing, sort of like in an outboard application. Try not just going in a straight line. Keep it moving a bit, sometimes it will help, sometimes it will make it worse. Even at WOT, I sometimes do this, because it will actually start to chine walk a bit. (A very little, I can only run low 70’s)

Mine will start to porpoise if I slow down less than 2800-3000 rpms, probably does it at higher rmps, but I automatically must do something, I cant really explain it. But under 2800-3000 and I can’t really stop it. Don’t really care, though, I probably come off plane at 30 mph or less. The boat really isn’t designed to tool around at that speed. Not a real good ski or tube boat.

You probably can’t eliminate it totally, but it’s a small price to pay for that extra top end over many other boats. 25’ Checkmates have been this way for as long as I can remember. Trust me, they are not defective.

-Craig

 

[Craig]

Russ,
You asked how much do we (with the same hulls) have to slow down to stop the porpoising. Slowing down is only going to make it harder to combat.

At 2800-3000 (30mph) or slower it gets hard for me to control it with a load, But by myself, no problem. If I go much slower than this, it’s just gonna come off plane.

At 3500 (40mph) it is very easily controllable. I can get a a grip on it with a load of passengers and running a high pitched speed prop. I don’t even currently own a prop that is any good for a big load.

Up passed 3600-3800 it is completey gone, unless I am automatically countering it and don’t know it.

I have tabs, and rarely use them. They can help a lot though. If you use them, think of them as making your boat’s running surface longer ,not a tool for stuffing the bow down into the water.

-Craig

 

[Craig]

I was just talking to a buddy about this. He says something he’s noticed me do is right after I plane off and it starts to bounce, I gun it a little and then I slow back down. I never really notice that I do that, but I do. Even after I’m on plane and at cruise speed, if porpoising starts due to a wake or whatever, I throttle fairly hard, get the bow to hold than came back down to the speed I want.

-Craig

 

[check253]

I owned a 253 for 4 years. It too would porpose at slower speeds if I didn't do anything to stop it. At slower speeds I would trim about half of what I would want at wide open throttle. I would also drop the K planes about 1/3 down. That totally stopped the porposing. I always used a 4 blade Hydromotive prop. Hope this helps.

Bill

 

[Ruus G.]

Thanks for the replies. The boat does feel good at 4,000 rpm. But I would like the opion of a lower rpm cruising speed. I also try to stop the bouncing by giving it more throttle. That does work. I agree slowing the boat down makes the porposing worse. I'm saying what good is a fast haul when you have to trim in and run the tabs in. That will slow the boat down.

I love the boat. Checkmate makes a quility product. My boat is customized how I like it. I'm going 67 plus on gps. I have gone faster but this is average. I have a 502 415hp efi. I would like to go faster. I would like to add a supercharger this winter. But if I can't get a handle on this porposing deal I will move on with another haul.

What kind of water was this boat designed for. I boat in a large river. On the smooth days some flat bottom boats get me along with some super fast jet skis. On ruff days we run good but the small advanti's Etc run the same water much smoother. It is awsome when there is a foot or so chop and there are no other boats around to change the waves.

 

[Craig]

Russ,

RE what water was the hull designed for: Mike or Kip would better answer, but I think it’s a good rough water boat. On windy, choppy days I can run WOT in estimated 2’-3’ chop/swells.

Was just out last night with a buddy. Had on a 28 labbed Bravo1, pretty smooth water. Ran like I always do. Then, let the boat slow down, did nothing with trim, or tabs or anything. Porpoise started at about 3000 rpms. I tried to pay attention to what I do to stop it, and all I really do is give her some throttle, maybe back up to 3300, and back down slow. As long as I come back slow and easy, the bow will hold….Now throw in some trim work and it gets even easier. I’m always doing something with trim or throttle…But I have to admit anything down around 2800 or less and it’s hard to stop it unless you use the tabs. I hardly ever touch the tabs.

(Now I get in my buddies Baja 272 or 25 OL, and it stays put from plane off all the thru WOT. Only thing is they runs 63-64 on gps and my boat runs 73 on gps. Same size boats, same power.)

-Craig