Jeff, any boat will porpoise when trimmed to the gills running WOT, which puts it high out of the water leaving the least amount of hull in the water for stability. I know mine will porpoise quickly if I try to get my top end too soon by trimming too much too quick. You've got to let it wind out a bit at a time inputting small amounts of trim until you're running a stable top end....

 

Reckless, with all due respect, not every boat will porpose at WOT. And I'm not talking trimed to the gils. I'm thinking Sunsation has a little bit of a curve at the back of the hull. I may be wrong. Just trying to find out from other owners with this little test.

 

Ok you got me. You'll never get a 26zx Donzi to porpoise, this I'll admit...

As soon as it warms up enough to fokk with crawling underneath, I'll check mine. Right now it's cold-arse rain. I mentioned in another post I'm going to lower my trim limiter to stop a 1/4" shorter than the Bravo max of 21.75" that mine is set at now. The idea being I think the limiter is set too high allowing for overtrim when trying to max the mph, especially trimming too quickly...

I don't know about yours, but mine lifts the bow quite easily which as I understand it, a hook inhibits bow lift by enhancing stern lift. I have a friend with a 26zx and he recently discovered via a factory rep that his year/model has a hook preventing his bow to lift enough to get the speed the boat should be getting with a 496HO. When he runs he's flat as a dime as if no trim yet swears he's trimmed to the stops...

 

Ya it's to cold and wet to crawl under mine as well CJ, But next chance I get I'll check mine

 

I spoke with Sunsation (Barrie) and he told me these boats are designed to run flat. Not carry the nose. Thats all fine, but if I can change that I may. The boat is fantastic all around. Just in real smooth water, I can't run WOT without bouncing down the river.

 

mine never porpoised...

 

I spoke with Sunsation (Barrie) and he told me these boats are designed to run flat. Not carry the nose. Thats all fine, but if I can change that I may. The boat is fantastic all around. Just in real smooth water, I can't run WOT without bouncing down the river.

i'd have to say that you're drive needs to be trimmed in slightly if you are pospoising.

any planing hull can be made to porpoise just by trimming the drive(s) too far out thereby raising the nose. If there is more gravity working on the nose of the boat then your boat is able to conteract with power through the outdrive... then your boat will begin to porpoise - just like a see-saw effect.

- jeff

 

I understand what your saying Jeff. But I am not trimmed excessively (in my opinion). By my marked trim gage #7 is level with the hull, 10 being down all the way. The boat begins to bounce at 5! Just out of level. It runs the quickest at around 3 or 2! My last boat and others can trim out to the point of blowing and still not bounce. I don't believe this is a trait shared by all boats. Again, I am just trying to find out if the hull is designed that way. And if others are as well.

 

Shouldn't 10 be all the way trimmed "UP"???

As you describe it seems odd with so little up trim (2-3 out of 10) that you're close to max speed trim much less at the porpoise point. What year boat and motor do you have? Do you have Bennetts or Kplanes?

 

Reckless, 10 on my drive trim gage is all the way in. 0 is all the way out. Level with the hull is 7. Best speed between, 3 and 2 with best water conditions. The boat starts to bounce at 5 at WOT smooth water. 280s K planes . 2001 hull with hp500efi. This may just be the nature of this boat, I just want to check if the hull is curved a little. I don't think I am running this boat wrong! I will check my own, just don't have time right now. Thought maybe some one this board does. If the boat does curve and I can remove it, I should gain speed. This is my reasoning! Is it wrong?

 

No, not wrong at all. I'm just curious about why your particular setup is behaving that way compared to mine with the 496HO and standard Bennett sport tabs. What speeds are you getting with that setup?...

 

I have only tested in smooth water. With a hand held gps the best was 71 mph. I was disapointed.

 

I can atest that our 288 do have bow bounce , with that said if I trim in it goes away , whether I am excessively trimmed or not I can`t say , I am at the same trim setting I used in the rough water , Canada Jeff and I run together every weekend , our boats speed seems to be identical so in flat water we are both trimming trying to get a 10th on each other to no avail , we both get to the point where we start to bounce the nose , we have the same setups 26lab finished with hp500, k- planes (set out of the way- up)I think if we are looking to hold the bow up we will need more power.

 

That is definitely strange. I truly believe the trim limiter is set too high on mine and as I mentioned before I will drop it a 1/4" to not go that high, because porpoise robs speed. I also cannot believe that you guys are only getting 71 with the HP500. Then again I suppose, you're only talking 45 more ponies over the 496HO. My best gps score is 69.2 under prime conditions and 68.5 under normal load, 67.## when bagged out. Are you guys at sea level?

Anyway, I'll be able to crawl around this weekend and check mine. Am I to check along the strakes, pad, or anyplace along the bottom?...

 

Not sure about the sea level thing, but I am talking smooth water. In ideal conditions, I think we'll see73 at least!
If you are going to check yours this weekend, look at the strakes, and the very bottom. As long as you are at the back. The bottom in front of the pad. I was told over 4 feet we should not see 1/8th of an inch. I too will check mine, but the marina that has it is busy with our annual boat show. So may not be for a while.

 

We're having a very nice weekend coming up so I'll be all over mine and maybe float it when I'm done cleaning it. So I'll definitely be checking it out...

 

That sounds good. Thanx in advance, I'll be eagerly waiting you results Monday morn. I think I'll have a chance to check mine mid next week.

 

Jeff the weather broke nice and I got a chance to crawl under and take a look. I couldn't find any indication of a "hook" as in a slight indentation. What I found was just the opposite. Half way to the little notch across the pad from the transom, it started an ever so slight curve "upwards" or a slight rocker. I measured down the pad, and up both sides with a perfectly straight 6 foot long 3/4" dowl rod that I verified by rolling across my pool table....

 

Reckless,
Check the bottom of your strakes.

 

His boat is on a trailer Dragon, I don't think he'll be able to. But I might. My trailer is getting painted soon, if not now, and the marina will block up my boat. Should be able to check the strakes. Was that the only place where you adjusted yours?
Thanks for the info Reckless. I am assuming your boat is on it's trailer right?

 

Bottom of strakes? Hmmm...okay. That's the one spot I didn't try. Unfortunately it'll have to wait a few more days again as I'm out the door heading to Baltimore, MD then Richmond, VA for meetings. Next weekend I tow her in a parade for St. Patty's day dressed in in Poker Run regalia to hype our up coming run in August. Oh and to have a few totty's at the post parade party...

Jeff, yes it's on the trailer totally coccooned in a huge tarp where eventually a nice carport will be built especially for the boat du-jour...

 

The only place there was any hook was on the back of the strakes.

 

Jesus, you gained 4mph with only reworking the strakes! How many 2, 4 strakes? Did you hapen to see the hook yourself Chris? Now, I have never known anyone who has blueprinted there boat, but, to rework your strakes for what it costed you, what did you say $2000.00 wasn't it? Seems a little dear in price! Was it a real big deal? Bitch to do? Did they rework the virtcle side of the strakes aswell? Are you tired of my questions?

 

Never tired of talking about boats. The only place there was any hook was in the strakes on either side of the pad. Yes, I took a 6' level set on the bottom of the strakes and there was about 1/4" hook in them. Now they are perfectly level. I don't know of anyone that does this any cheaper and I didn't want to try myself and really cause a problem. They had the boat about 3 days. Wayne says the hook is put in there to help the boat turn better but I haven't noticed a difference in the handling. Besides,I 'm not running any slolom courses mostly straight out speed.

 

So it was just the bottom two. And you gained that much! Cool. I wonder if its the same with our size? Thanx for the info. Sounds like there are some pretty fast 288's coming to Metro this year. I'm going to need as much as I can get.