Re: 259 Convincor w/ 600hp
 

I have the same problem in our 2000 259. What prop are you running? We have a Mirage Plus 23P 3 blade. The porposing is obnoxious when the boat is full of people. I have been told a 4 blade prop will help. I really enjoy the ride of our boat beyond 4000RPM and some positive trim, carries the bow well. However getting there is not fun when there are four people sitting in the back seat. I am curious to hear other comments on this problem by Checkmate owners. I have tried all sorts of drive positions and tab positions, so I believe it is just a handling characteristic of the hull design and not user error.

Re: 259 Convincor w/ 600hp
 

My '99 259 has the same ride characteristics at slow speed. I have the same problem when my wife comes with me. She is only comfortable going slower. Of course, then she complains about the propoising. If I run anywhere below about 40 mph, it will do it. While attempting to maximize speed, I have run several props. None of which helped the porpoising. The only thing I found was to bury those stock junk Insta-Trim tabs. 2 years ago, I switched to Dana Marine hp-1000 tabs. Now the porpoising goes away with a little down tab, about #4 on my mechanical indicator. BTW, I am running a 25" P-5X for a prop.

Re: 259 Convincor w/ 600hp
 

I have the same boat and it does the same thing. There is a thread that I started about (why does a boat porpose) in the general threads. There is some good info there.

Russ

Re: 259 Convincor w/ 600hp
 

I run 380 tabs and that alone will stop the problem. Then again I never cruise under 55mph. Thats only 3000rpm for me. Below that I'm wasting fuel. BTW I'm running a 5 blade with a 2" shorty, but if you have stock power 5 blades are not the best for you.

Bottom line- get better tabs and a 4 blade bravo 1 prop.

Re: 259 Convincor w/ 600hp
 

Dave,
That is because your wife is not a sissy like mine. Did you see that Sonic?? I didnt know you got the shorty back on.

Re: 259 Convincor w/ 600hp
 

You need to pick them young, my wife was 17 when we met. Now she loves speed.

What Sonic???

The shorty lower was back to me in 10 days, Bmax takes care of me. But it may blow again, I just raised the boost... Again. 17Ibs now! I'm not advertising the top speed any more.

Re: 259 Convincor w/ 600hp
 

here's the link

Re: 259 Convincor w/ 600hp
 

I thought you told me that you were running with a twin engine Sonic last weekend. Or maybe it was a Scarab?

Re: 259 Convincor w/ 600hp
 

Scarab.

The weather did not cooperate. But I WILL see him before the end of the summer.

Re: 259 Convincor w/ 600hp
 

For best performance you should not keep the same prop on that you use for top speed when you put a load of people in a 25’ Checkmate….Prop it to run close to max rpms at WOT for the load you have. Actually, I get lazy and leave my speed prop on, and I can still control the porpoising down to about 3000, 3200-3400 for sure, with 4 people. Russ G is probably getting sick of my saying that, but it is controllable down under 4000 with trim and throttle work. I rarely use my tabs unless I’m running thru some nasty stuff. Under 3000 and it’s very difficult to stop or controll. Just the way the hull is, it has a fast cruising speed and is an excellent top end runner.

-Craig

Re: 259 Convincor w/ 600hp
 

I have to say also that, regarding these 25'ers and the porpoising issue, It is better also when you are running a little more hp. I have a 496HO/425hp and I would have to admit it makes it a litttle more easier to control...

-Craig

Re: 259 Convincor w/ 600hp
 

Ckflyer I'm not sick of you saying anything. Its all good and your just trying to help. But what makes me wonder is many people have this exact boat 25 Convincor. We all have different drives, different props., different engines and HP. We all have the same problem! Porposing! Some have learned how to contol it or mask the problem. Some are better at driving the boat. I exept that and I'm gettin better at driving mine also. But I have been boating for many years and didn't realize before I had this boat- I cant drive. I also had a 240 Baja sport, A 23 Worklock off-shore vee, A 30 Scarab and some smaller boats and I never bounced up and down the river before in them. And I gotta say that the 23 Worlock was a super fast haul!!! I'm not trying to down Checkmate. Out of all the boats I had this is the best built. And thats the reason I'm trying to get a handle on the porposing issue. Thanks for all the advice.

Russ

Re: 259 Convincor w/ 600hp
 

Russ, I here ya....I also think your 251 is even more difficult, my 270 (259) being the easiest of the three 25' models they have (251, 253, and 259).

-Craig

Re: 259 Convincor w/ 600hp
 

One thing that all checkmates seem to have in common is the desire to ride on their tails. (They love bow lift) In my opinion, that’s what causes the porpoising at lower speeds. It also allows these hulls to run so well at WOT. My hull is presently the latest design from Checkmate in the 26" range and it also has porpoising issues below 45mph.

But hey who wants to go below 45 anyway?

Just kidding…

Re: 259 Convincor w/ 600hp
 

My old 242 Convincor use to porpose at slow speeds too. I called it the Checkmate Hop. They all seem to do it, it can be corrected with the tabs and the throttle.

Re: 259 Convincor w/ 600hp
 

Wild Willy,
I am not sure about the ride of 280ZT. I will tell you though our 259 Convincor will not porpose at 25MPH with the drive tucked down. However that is not the porposing zone in this hull. The porposing starts around 33MPH GPS and stops around 47MPH GPS regardless of where the stock trim tabs and drive are set at. I agree with checkmate454mag and ZT260 that larger tabs will help correct this problem. I disagree in implying a 25 Convincor porposing between these speeds is do to driver error or a lack of experience.

Re: 259 Convincor w/ 600hp
 

Yes I agree, the porpoising is not the result of driver error, it is a characteristic of these hulls, but you can use drivng technique (trim, throttle and tab work) to correct or control it. I think we are all agreeing on that?

Main thing though, is to get the right prop on it....We got to get off the 25'er porposing issue, just the way it is, it's not that big of deal. Checkmates aren't the only ones. The overall ride of my 270 excellent and very hard to beat.

-Craig

Re: 259 Convincor w/ 600hp
 

I agree with that.. While Checkmates are not comparable to Outerlimits, I think they are a great boat for the money.

Re: 259 Convincor w/ 600hp
 

Build quality and price on the 259 Convincor is extremely competitive to anything out there. And the ride at 50MPH for a 25 in moderately rough water is outstanding. I just need to buy larger tabs.

Re: 259 Convincor w/ 600hp
 

I also need 600HP. :evilb:

Re: 259 Convincor w/ 600hp
 

And once you have 600, you will want 700. I have 680, and want more. It's an addiction.

Re: 259 Convincor w/ 600hp
 

No comment.

Re: 259 Convincor w/ 600hp
 

680 How fast is that thing?! A little over 400 and I'm pushing close to 70gps.

Russ

Re: 259 Convincor w/ 600hp
 

Maybe,
If I could just keep the outdrive together.

Re: 259 Convincor w/ 600hp
 

I get 80 GPS in good conditions.