Party Deck won't plain

[1580rick]

We have 2000 Sun Tracker Party Deck with a Mercruiser 4.3 that won't plain out. Had a 21 pitch prop on it and changed to a 19, also added a hydrofoil. Still won't plain. Motor sounds good, turns 4600 rpm's. Boat runs 35 mph, outdrive trim works. Can go from full down and up until it starts free spinning. Boat empty still will not raise the nose of the boat. Any ideas???

 

[bruceb58]

Is this something new that is happening?

35 MPH is on plane.

How are you measuring your speed?

 

[1580rick]

Just bought the boat. Measuring speed off of speedometer and gps. The nose of the boat comes up a little when I first start trimming, but very little . Water spray comes out from under the very front of the the boat the whole time. I have the same boat only with a 150 outboard and a friend has one with the 3.0 I/o and they both plane out quickly.

 

[Alumarine]

As Bruce says, it's planing.
What are trying to accomplish, go faster or get more of the "front" out of the water?

 

[Eric 3.7LX Alpha 1]

We have 2000 Sun Tracker Party Deck with a Mercruiser 4.3 that won't plain out. Had a 21 pitch prop on it and changed to a 19, also added a hydrofoil. Still won't plain. Motor sounds good, turns 4600 rpm's. Boat runs 35 mph, outdrive trim works. Can go from full down and up until it starts free spinning. Boat empty still will not raise the nose of the boat. Any ideas???

Here is a thread on adding the hydrofoil fin:
http://forums.iboats.com/forum/gene...ine-topics/469308-hydrofoil-stabilizer-or-not

 

[1580rick]

Trying to get the front of the boat out of the water. Gets everything wet, including my face.

 

[Rick Stephens]

Probably time for trim tabs. Should do more than a foil since they have more surface area. Tabs would definitely push the stern up which should lighten the bow a lot. I found trim tabs lowered my planing speed from 18-19 MPH down to 12-13.

Is it possible that the floatation foam in the hull is waterlogged and you're pushing a lot more weight?

Rick

 

[bruceb58]

Putting tabs on is going to force the bow into the water, not out if it.

That boat is a strange design. I would want to find out the experience of other owners before I did anything.

 

[1580rick]

Boat had been sitting with the plug out, and had problem as soon as I took off. When I got back I pulled plug and some water ran out, but not much. I think the foam should be dry. My friends boat is exactly the same boat, only with a 3.0 and he doesn't have any problem. Although the transom is made different on my 2002 with a 150 outboard, it is basicly the same boat. It trims out so fast that when I'm pulling with it ( tube, skis, knee board ) I just leave the trim at 1/4 the whole time.

 

[Rick Stephens]

Putting tabs on is going to force the bow into the water, not out if it.

Not been my experience. Trim tabs after install showed an immediate change from plowing until the boat slowly rolled up into plane, to popping right up in half the time and distance. The effect sitting in the pilots chair is that the stern lifts up sooner with no felt effect/change on the bow. On plane the entire boat comes up as opposed to just the bow. I'm not saying they are a perfect solution, they did make enormous improvement in my fuel burn and low end plane speeds.

Best way to know whether you are carrying around a bunch of water is to weigh your boat and compare to either spec or another boat. With your buddy owning one it should be easyish - you can account for his heavier motor and structure over your outboard. You should be planing out faster, especially as you have more HP and lighter weight.

Rick

 

[smokeonthewater]

The difference is the definition of "plowing" you are talking about the stern being low and the op is talking about the bow being low....

These are two very different situations... The tabs are great for lifting the stern but lifting the stern lowers the bow.

O/P how about a different prop... If your current prop is a stern lifting design then a change to a bow lifting prop might be all you need.

 

[bruceb58]

Not been my experience. Trim tabs after install showed an immediate change from plowing until the boat slowly rolled up into plane, to popping right up in half the time and distance.

He is talking about its behavior at 36MPH. I can pretty much guarantee he is already planing.

 

[1580rick]

When I got the boat it had a alum 21P prop, that the seller said came on the boat new. I changed it to a 19P stainless off of my 150 OB. My RPM's went from 4200 to 4600, but it did not help problem. I don't know the difference in speed because to speedo did not work and there was no gps on it when I tried it before. I don't what to look for when looking for a bow lifting prop. Not familiar with the tabs either. Are they hard to install? Right now I'll try about anything...

 

[littlerayray]

Are you boating in choppy water how is it on glass and is the out board deep enough in the water

 

[1580rick]

littlerayray it is an inboard. bruceb58 The problem is from 0 to max speed which seems to be 36 mph. On the other 2 boats: from 15 mph and above you can't reach the water reaching over the side if you are sitting in front of the driver. This one you could reach the water from the nose of the boat at max speed. At max speed and trimmed as high as I can without the prop free spinning, it is still pushing a lot of water forward and out from the front of the bow of the boat.

 

[littlerayray]

Ok sorry I misread well that's a conundrum

 

[1580rick]

No problem. Thanks for trying to help.

 

[littlerayray]

It also sounds like your Bow is very heavy I would get your boat weighed

 

[QC]

1) It is definitely planing as Bruce and others have pointed out.
2) Sounds like the bow is heavy. Have you pulled EVERYTHING except one life jacket out of this thing and tried? One person?
3) Where are the batteries? Where is the fuel tank? Tried almost empty of fuel?
4) I believe your first post says you tried without the hydrofoil. Seems like a foil (and tabs) could make this particular issue worse.

All of what I have suggested is to get more data, and hopefully in an organized manner. Typically a 4.3 compared to a 3.0 and an OB would be quicker to plane and heavier in the rear. Something is driving the bow down. First thought was the Hydrofoil, but it does appear you tried without that first.

 

[flipbro]

Is the bottom of the hull strait?