12' Pontoon/Fishing boat nose diving issues!!!!!

[goosemasterkl]

Asking for a friend of mine who has a 12' pontoon/fishing boat with a 3.5 hp Mercury 4 stroke outboard. The issue he's having is that when he tries to power up the engine to take off the front of the boat wants to go down under the water. He's messed with how the trim is set and nothing will help. Any suggestions or solutions would be appreciated.

 

[Texasmark]

What does messing with the trim mean? What is the weight distribution in the boat? What is the load vs flotation area.....does the boat sit low in the water when at rest? What do the tubes look like in the front....concave or pointed? Pictures would help in answering these questions. You want help participate in the solution....better than us just wild guessing.

 

[tpenfield]

3.5 HP vs. 12 foot pontoon . . . Not much HP.

Is the bow heavy with fishing gear or other stuff?

Do the Pontoons have water in them?

 

[airshot]

To many guesses could be made, need real information.

 

[Texasmark]

3.5 HP vs. 12 foot pontoon . . . Not much HP.

Is the bow heavy with fishing gear or other stuff?

Do the Pontoons have water in them?

I would think that once underway, any water in the tubes would move to the rear making the boat stern heavy, not bow heavy....force applied action/reaction physics thing.

 

[airshot]

We can't see the craft, so we can only guess, to much weight up front?? You gotta experiment with loads.

 

[tpenfield]

I would think that once underway, any water in the tubes would move to the rear making the boat stern heavy, not bow heavy....force applied action/reaction physics thing.

Most pontoons have 2-3 chambers as a safety feature, so a leak cannot flood the entire pontoon. So, it could be a leak in the forward chamber of the pontoon.

As @airshot mentioned, we have no visual to go by. The OP & Friend may have to figure it out based on the comments so far.

 

[Chris1956]

Is the motor shaft length correct for the boat? Longer shaft motors mounted on shorter shaft transoms, tend to drive the bow down. Trimming should help a bit, but raising the motor up on the transom is a better idea.