Re: Need ideas to stop porpoising?
 

Went fishing yesterday(did not say catching,bad day, 3 dog fish and 3 lingcod,ling cod is closed). The lead is out and the boat preformed great. Now to work on the prop, I was able to run it up to 6000 rpm/44mph/GPS and still just a touch of throttle left. RPM range is 5000-6000 rpm, I am trying to get them to swap out the prop for a 4 blade as suggested above.

Re: Need ideas to stop porpoising?
 

You want to be able to hit the upper end of maximum recommended with the boat at max gross weight. Load it up with full fuel, max people, and max equipment, and you should be able to hit the upper end of max rpm range.

You should be able to hit max of max at max.

I can hit 5800 rpms with full fuel and 7 people on the boat, along with beach and camping gear in the cabin. I expect to never spin a hub from overloading, or have a shortage of low-mid-range power/torque in an emergency.

Re: Need ideas to stop porpoising?
 

Went down south and picked up my new 4 blade prop this AM. Just installed it and hopefully will be able to get out tomorrow or Saturday. I am anxious to see how it performs compared to the 3 blade. Talked nice to the dealer and he ended up taking my 3 blade prop back and we split the difference in the price on the 4 blade Powertech. :)

Re: Need ideas to stop porpoising?
 

Well, now I am satisfied w/the preformance, no more porpoising. Got the new 4 blade prop installed and was able to run it yesterday. I can tell the difference in the handling, especially in the no wake zones, also jumps up on plane fast and lifts the stern up. I was able to get 5900 RPM , just had the motor trimmed so top of the motor was level w/the water. It looks like I am going to be getting between 7-8 GPH at moderate speed of 28-30 mph @ 4000 rpm. Now I am really a happy camper. I also had an outstadning day fishing, caught the largest salmon in my life for me. My scale quits at 40# and it still needed more, somewhere around 45#s.

Re: Need ideas to stop porpoising?
 

Good deal - sounds like it might stay on plane at a lower speed also. If running in flat water, you might be able to squeeze a little more max rpm/mph out of it with trim adjustment. Most folks trim out until it either starts to porpoise or the prop ventilates, then trim down just enough to stop that. This will minimize hull wetted surface and drag, but won't be the best ride! Trim tabs should also be all the way up for max speed.

Re: Need ideas to stop porpoising?
 

Sounds like someone is having a really good day.

Isn`t it amazing how much a prop can affect attitudes. Yours, the boat`s ,and even the fish are excited! Now go buy a bigger scale!
GFS

Re: Need ideas to stop porpoising?
 

Hey great news. Now let's see pix of that monster. 40+ pounds???????? Did you smoke it or just filet it out and share it with your closest dozen neighbors? I'll bring the bagels and capers.

Re: Need ideas to stop porpoising?
 

Brian, you have got to learn to catch your own fish someday :D

Re: Need ideas to stop porpoising?
 

[image]http://http://i44.photobucket.com/albums/f4...6/DSCN0422.jpg[/image] Maybe this will tranfer. Didn't transfer but at least you can look here. I managed to do this a couple weeks ago, guess I am having a senior moment.
[image]http://http://s44.photobucket.com/albums/f41/gss306/?action=view&current=DSCN0422-2.jpg[/image]
I had to click on the img code to finally get it to transfer, hey! only took me about 30 minutes.

Re: Need ideas to stop porpoising?
 

[image]http://i44.photobucket.com/albums/f4...DSCN0422-1.jpg[/image]

Re: Need ideas to stop porpoising?
 

shes a beauty, Gary. Nice catch. Congratulations on resolving the porpoising issue! Post a couple of pics of you boat, too - I've never seen a walkaround model. Tight lines and conserve the fishery, no Salmon in CA this year, on the other hand a couple of years back we did find enough local steelhead down in San Diego forcing the feds to protect the coastal streams al the way to the border. The species had been declared extinct south of Malibu creek back in 1971 or so. We'll never have a steelhead fishery again but I sleep better knowing they still exist! -Gill

Re: Need ideas to stop porpoising?
 

[image]http://i44.photobucket.com/albums/f4...6/DSCN0133.jpg[/image]

Re: Need ideas to stop porpoising?
 

Thats the best of both worlds; 360* fishability and a cabin to get out of the rain. There was one of those for sale in Naples, Florida a couple years ago. No trailer or motor..I believe they wanted $5000. I probably should of grabbed that one :(. Glad you and your Honda dealer got it all worked out.

Re: Need ideas to stop porpoising?
 

Not being critical here, do I see a bleach jug in the hand of the fella on the boat? That stuff will kill your gel coat. It will make the gel coat porous and you will have to keep using it. May want to clean the gelcoat and seal it with wax or wax & cleaner such as 3M.

Re: Need ideas to stop porpoising?
 

No, it is not bleach, just a citrus based cleaner used by a lot of boaters in the area.

Re: Need ideas to stop porpoising?
 

I was out again today, every thing's running smooth, looks like I am going to be getting between 7-8 GPH at 3600 RPM and 26 MPH. That is also including runnig the 15 HP Honda kicker for about 6 hours each day. So, maybe I am closer to 7gph. I was hoping for a little better but that is really better than the old Merc 200 carbed engine.
People want too much $$$ for fuel flow guages, I could have gone for Honda digital guages w/it for addition $850. That is pretty expensive to how much gas you are burning. It doesn't feel so bad now that gas is back down to $3.37.9 here.

Re: Need ideas to stop porpoising?
 

Thats more than double the MPG of my 20MA. I have a NavMan 210 fuel moniter. It'll give GPH, fuel used, or fuel left. $125 @ Bethel-marine.com . I've decided I need a backup for troublesome fuel gauges.

Re: Need ideas to stop porpoising?
 

TARPUN, How much of a job is it to install one of the F210s?
Are they accurare?

Re: Need ideas to stop porpoising?
 

Gary, It's an easy install. 2" hole in dash, the fuel flow transducer goes inline in your fuel line after your fuel filter (between filter and engine) in an upright position. Hook up pos. & neg to your 12 volt system and you're good to go. The toughest part is the hole in the dash.

It seems to be pretty accurate but I really don't have a lot of time on it. I would say it's within their claimed accuracy of 5%. It is supposed to able to be calibrated by the user to within 2%.

Re: Need ideas to stop porpoising?
 

Thank you for the quick response. I already have a vacant hole plugged in the dash from the old instruments. My Honda/Racor filter is in the motor well, so that would leave wires exposed, how did you deal with that?

Re: Need ideas to stop porpoising?
 

My fuel filter is mounted on the transom inside of the access door beneath the starbord side stern cooler/baitbox. The fuel transducer mounts next to it. On my application I just fed the cable under the deck back to the console. The transducer cable is the only wire that needs to leave the console and it's about the size of maybe #10 wire. You could bundle it with your motor harness or at least feed it thru the same access.

Re: Need ideas to stop porpoising?
 

Well maybe you guys can help me with my problem. I have a 1984 Seacraft Sceptre hardtop with a 1999 200hp mercury optimax. I would like to keep this motor on the boat until I can afford a new honda 4 stroke. I have the motor mounted on a armstrong bracket. I know I have to raise it 1-2 holes after speaking to a tech from armstrong brackets. My problem is also a prop. I need a different prop. Im running a 14 3/8 x 15 ss prop and Im not getting the rpms or the speed that Gary was getting with his 200 mercury. At cruise I have to run 4600 rpms just to go 25 miles an hour. At wide open throttle I get 5400 rpms and get 35 miles an hour. The motor is rated for 5000-5750 rpms, and I would like to get as close to that 5750 number. Will that 4 blade rev prop help me in my situation. Keep in mind the weight of the hardtop and the radar arch. At this time I know I have the wrong prop and I know I have to raise the motor either 1 or 2 holes depending on the measurement. So any input on this would be appreciated guys.

Re: Need ideas to stop porpoising?
 

Based much on what has been well documented on this site, I'm gonna guess that you'll pick up some of those rpm by raising the motor. Start there. 1 hole at a time or whatever to takes to get the anti-cavitation plate 1 to 1-1/2" above the bottom of the hull with the a-c plate parallel to the bottom of the hull. Seems to be the magic number...

I don't see a 200 optimax having trouble turning that prop but as it's said some props are easier to turn than others. What is your prop style/model? Based on what's out there for that motor the your current pitch is about as low as you can go, I think any thing lower will will likely be detrimental to your overall performance.

Tend to the motor height first. You may find yourself pleasantly surprised. Keep in mind your full windshield and top and radar add considerable drag compared to Gary's walk-around windshield. I think if you pick up the rpm and squeeze another couple mph you're smiling. Good luck! Post your results, like to here results.

Re: Need ideas to stop porpoising?
 

Gilly's right. Raise the motor to pick up rpms. You could get an extra 200-400 rpms by doing that. Of course, you might not, too. But you will gain something.

35 mph WOT in a Sceptre with a hardtop running a 200 Opti is good numbers. 25-26 mph should be your normal cruising speed with that motor. I recently sold a '74 Tsunami with an '89 225 Looper Johnson, no hardtop. I ran WOT at 5400 rpms, and 37-38 mph with the bimini down. Bimini up I could only get 34 mph.

Re: Need ideas to stop porpoising?
 

Thanks for your input guys.The boat is on land now, and just yesterday I went down to the boat to cover it before the storm and I took some measurements. I put a straight edge on the bottom of the hull extending out to the cav. plate on the lower unit and I measured 2 1/4 inches from the bottom of the hull to the cav. plate. According to the tech from armstrong he said for every foot your motor is away from the boat you have to go up 1 inch from the bottom of the hull to the cav plate. My motor is 38 inches away from the boat, so according to my measurements I should be 3 inches above the bottom of the hull. Right now the motor is 2 1/4 inches so that tells me if I go up 1 hole then I should be at the exact height. Every hole on the motor is 3/4 inches apart. So I m going to raise it up 1 hole and hope for the best. The prop is a mirage prop 14 3/8 x 15. And you guys think thats the right prop. I guess after hearing the numbers that gary was getting with the walkaround I was hoping to get atleast the high 30,s out of the motor at wot. But like you said frank that hardtop and radar arch has some weight to them. any more input would be appreciated, thanks guys. Peter

Re: Need ideas to stop porpoising?
 

It's not the weight so much as it is the wind resistance, although the weight does matter. The hardtop is like deploying a parachute behind you to slow you down.