Help, bow won't lift up when accelerating
 

Actually, my problem is a bit different, but maybe someone can help.
I've a 12 foot skiff and a 1962 Johnson 10hp which is ok for this boat. At
cruising speed, the bow seems to be lower than it should and sometimes plows
into waves. I have tried adjusting the angle of the engine and have myself, the
fuel tank and a milk crate of misc items in the back of the boat, but still has
not improved matters any. With the motor tilted forward, acceleration has the
bow pointed way up until I get on plane. At 90% throttle (~18mph) on smooth
water, the bow seems to want to dig in some and makes handling scary. What
adjustments can I make?

Help, bow won't lift up when accelerating
 

Since you've tried trimming the motor and putting the weight in the rear. I
think you're screwed by the hull design.

-W

"Guy Noir - private eye" wrote in message
...
Actually, my problem is a bit different, but maybe someone can help.
I've a 12 foot skiff and a 1962 Johnson 10hp which is ok for this boat. At
cruising speed, the bow seems to be lower than it should and sometimes
plows
into waves. I have tried adjusting the angle of the engine and have
myself, the
fuel tank and a milk crate of misc items in the back of the boat, but
still has
not improved matters any. With the motor tilted forward, acceleration has
the
bow pointed way up until I get on plane. At 90% throttle (~18mph) on
smooth
water, the bow seems to want to dig in some and makes handling scary. What
adjustments can I make?

Help, bow won't lift up when accelerating
 

Make sure that the bottom of the boat is straight and not deformed from
sitting on a poorly fitted trailer for a long period.
"Guy Noir - private eye" wrote in message
...
Actually, my problem is a bit different, but maybe someone can help.
I've a 12 foot skiff and a 1962 Johnson 10hp which is ok for this boat. At
cruising speed, the bow seems to be lower than it should and sometimes
plows
into waves. I have tried adjusting the angle of the engine and have
myself, the
fuel tank and a milk crate of misc items in the back of the boat, but
still has
not improved matters any. With the motor tilted forward, acceleration has
the
bow pointed way up until I get on plane. At 90% throttle (~18mph) on
smooth
water, the bow seems to want to dig in some and makes handling scary. What
adjustments can I make?

Help, bow won't lift up when accelerating
 

Also make sure the motor is not mounted too low or high on the transom. The
cavitation plate should be within 2" of the bottom of the transom but not
below it.
Also what condition is the prop in. Having a good clean prop that has a
little bow lift in it will help. Any prop shop can add bow lift to the
blades.

--
Tony
My boats and autos - http://t.thomas.home.mchsi.com



"Guy Noir - private eye" wrote in message
...
Actually, my problem is a bit different, but maybe someone can help.
I've a 12 foot skiff and a 1962 Johnson 10hp which is ok for this boat. At
cruising speed, the bow seems to be lower than it should and sometimes
plows
into waves. I have tried adjusting the angle of the engine and have
myself, the
fuel tank and a milk crate of misc items in the back of the boat, but
still has
not improved matters any. With the motor tilted forward, acceleration has
the
bow pointed way up until I get on plane. At 90% throttle (~18mph) on
smooth
water, the bow seems to want to dig in some and makes handling scary. What
adjustments can I make?

Help, bow won't lift up when accelerating
 

On 07 Oct 2003 19:32:23 GMT, olsucks (Guy Noir -
private eye) wrote:

Actually, my problem is a bit different, but maybe someone can help.
I've a 12 foot skiff and a 1962 Johnson 10hp which is ok for this boat. At
cruising speed, the bow seems to be lower than it should and sometimes plows
into waves. I have tried adjusting the angle of the engine and have myself, the
fuel tank and a milk crate of misc items in the back of the boat, but still has
not improved matters any. With the motor tilted forward, acceleration has the
bow pointed way up until I get on plane. At 90% throttle (~18mph) on smooth
water, the bow seems to want to dig in some and makes handling scary. What
adjustments can I make?

Clams and Mike have given good advice. You didn't say if you had an
aluminum or wood hull. Knowing that would help.

Check the hull for "hook" (bend) along the keel if it's wood, or
larger dents, if it's aluminum.

Skiff's and jon-boats do tend to get a bit squirrely at speed, but the
bow should not be digging in for no reason. I've run a 10' jon with a
9.9hp, and it was interesting, but the bow didn't dig.

Good luck,
....carry on.
noah

To email me, please remove the "FISH" from the net.

Help, bow won't lift up when accelerating
 

On 7 Oct 2003 18:14:11 -0500, noah
wrote:

Check the hull for "hook" (bend) along the keel if it's wood, or
larger dents, if it's aluminum.

==============================

Assuming it is a hydrodynamic hull issue as opposed to motor too low,
etc., I'm wondering if it could be corrected by attaching a small
lifting wedge or step near the middle of the bottom.

Help, bow won't lift up when accelerating
 

Wayne.B wrote:
On 7 Oct 2003 18:14:11 -0500, noah
wrote:

Check the hull for "hook" (bend) along the keel if it's wood, or
larger dents, if it's aluminum.

==============================

Assuming it is a hydrodynamic hull issue as opposed to motor too low,
etc., I'm wondering if it could be corrected by attaching a small
lifting wedge or step near the middle of the bottom.


IF the motor is properly attached to the transom, my guess is that he's
got a problem on the bottom of the boat, as mentioned. A 10 hp outboard
is more than sufficient to move a 12' skiff up on plane properly so it
is running with a bit of bow rise.

Help, bow won't lift up when accelerating
 

On Tue, 07 Oct 2003 20:47:28 -0400, Harry Krause
wrote:
IF the motor is properly attached to the transom, my guess is that he's
got a problem on the bottom of the boat, as mentioned. A 10 hp outboard
is more than sufficient to move a 12' skiff up on plane properly so it
is running with a bit of bow rise.

================

It didn't sound like getting on plane was an issue, but once he did,
the bow came down and started to dig in instead of staying up a
little. As other have speculated, that could be caused by a hook in
the hull shape (either static or dynamicaly induced by water
pressure), or possibly by the propeller being too far underwater and
trying to lift. It could turn out that the boat was just not designed
to run at planing speed and will need some fiddling around to get it
there.

When I was a kid on Lake Ontario my brother and I had a lightly built
14 foot wooden row boat which we powered with a 7 1/2 hp Merc. It was
never designed to run on plane of course, but it would with that Merc.
You could watch the bottom of the boat flex however and the dynamics
were constantly changing as a result. When we took it out solo we'd
put a 30 pound rock in the bow to hold it down.