Porposing on a 14' aluminum v-hull

[sierra 18]

Afternoon all:

I have a 14' 2000 Lowe v-hull fishing boat, with a 35 HP Johnson 2-stroke center console. I was on the lake today, alone, so no one up front. When I was bringing the boat to speed, after moving over the bow wave and going to plane/gaining speed, I began to porpose, so much so that it was getting out of control and I had to cut the speed. The water was very calm, so it wasn't an environmental issue as far as I can see.

I have power trim, and I start with the motor down/in, depending on your perspective, and I throttle up gradually. When I beat the bow wave, I generally trim the motor up in small increments until I'm flying along the surface nicely. Today, as I began to really move, the porpose action began. It was pretty severe, so my first move was to cut speed and stop the action, rather than trying to experiment with the trim.

I've searched the forum on this topic, but since the other posters on this issue have different boats than mine, I thought I'd ask your opinions as it concerns my 14' aluminum.

Many thanks in advance for your advice and opinions,

Chris

 

[mpsyamaha]

Re: Porposing on a 14' aluminum v-hull

first thing i would look at is what the motor height is on the transom. sounds like it could possibly be that its too low. if the ventilation plate is at or above the bottom of the hull then im not sure what your problem is... maybe try to distribute weight differently and see what happens.

 

[Alumarine]

Re: Porposing on a 14' aluminum v-hull

Trim down/in to stop porpoising.

 

[Capt'n Chris]

Re: Porposing on a 14' aluminum v-hull

Is this your first time out alone in this boat? Or, is this something new you're experiencing out solo?

 

[Moody Blue]

Re: Porposing on a 14' aluminum v-hull

Trimming IN will reduce the severity but will also affect the performance and handling of the boat.

I had the same problem with a 14ft FG hull, and after many failed attempts to correct it, I installed a set of trim tabs.

Completely eliminated the porpoising and noticably improved the ride and handling of the boat.

 

[sierra 18]

Re: Porposing on a 14' aluminum v-hull

Is this your first time out alone in this boat? Or, is this something new you're experiencing out solo?

Interesting. Yes, first time out on my own. I had filled the livewell (which is just in front of the side console where I sit) to hold all the fish I didn't catch , but no one up front on the forward seat. If this is a load/weight issue, then can I remedy it with trimming the motor?

I have to research trim tabs, no idea what they are or how much they cost.

 

[Capt'n Chris]

Re: Porposing on a 14' aluminum v-hull

Exhaust all other possibilities before hanging on "tails and tabs".

 

[5150abf]

Re: Porposing on a 14' aluminum v-hull

That can be caused by iother things but generally it is a trim issue

The engine tries to lift the boat but it is too heavy so it drops and the engine tries to lift it again ect, normally if you trim down a bit it will go away.

You might also try to raise your engine one or 2 holes on the transom, mine is high enough that it cavitates before it will porpoise, also raising the motor normally makes the boat run better in general.

 

[kenmyfam]

Re: Porposing on a 14' aluminum v-hull

Set up is huge for correct performance. Motor height, trim, fuel tank location, loading of gear and people all play a large part in the boats stability at varying speeds. Get some more weight up at the bow and see what results you get.
Reading your other post both you and the live well were on the same side of the boat ???? that will put a lot of one sided weight on the outfit and will certainly not help stability either. Try again with the live well empty and see what you get.
One other thing, what max HP is your boat rated for ???

 

[capt sam]

Re: Porposing on a 14' aluminum v-hull

that's a fairly large motor for that boat, move everything up front, fuel tank, battery if you have one, cooler, everything. Small boats are all about weight distribution not necessarily using tabs.

 

[sierra 18]

Re: Porposing on a 14' aluminum v-hull

The live well is just forward of the console. I was out the other day with a friend, and with him sitting in the forward seat of the front casting deck, we never had a porpoising issue the whole day. I'll take that to mean its a load distribution issue, more affected when I'm in the boat alone.

Thanks for weighing in all,

Best,

Chris

 

[spunkyjr]

Re: Porposing on a 14' aluminum v-hull

Yep it's the weight distrubition. Mine does the same thing only with a 25 Merc. Gets kinda scary out there I have to slow down. Had mine going 32 mph and that was too much. THat was just me and the gas tank in the boat.

 

[SteveRoss]

Re: Porposing on a 14' aluminum v-hull

Same problem here. A couple weeks ago, I got a "new to me" boat. It's a 14' Sea Ark with a modified V hull and a Honda 15 HP. With just me, the gas tank and battery in the stern, it will porpoise right after it planes out. I started with the motor trimmed down/in, and no amount of trimming out seemed to help.

A friend suggested getting some weight forward, so I bought 100 pounds of landscape rocks and put them in a box up on the forward casting deck. Now, the porpoise problem has gone away, but something tells me that the "box of rocks" spells inefficiency !!

So now, I'm in the process of moving the gas tank and battery (electric start/tilt engine) up forward.

The porpoising is a little scary at my age..... HAHAHA !!!