planing
 

I have a 17 ft, older trihul. The more throttle I give the more the bow
stands up. I was reading recently about planing. Would my boat be
considered a displacement boat? or is it just set up wrong.

The boat has a Volvo 140 i/o with now trim tab. There are some "trim
plates" on the back.

Also, am I missing some "trim" thing on my outdrive? Something like this
http://www.cabelas.com/cabelas/en/te...jpg&hasJS=true

Thanx,
Mike

planing
 

On Fri, 5 Mar 2004 11:15:22 -0800, "MikeG" wrote:

I have a 17 ft, older trihul. The more throttle I give the more the bow
stands up. I was reading recently about planing. Would my boat be
considered a displacement boat? or is it just set up wrong.

The boat has a Volvo 140 i/o with now trim tab. There are some "trim
plates" on the back.

Also, am I missing some "trim" thing on my outdrive? Something like this
http://www.cabelas.com/cabelas/en/te...jpg&hasJS=true

Thanx,
Mike

What are the trim plates on the back? Are they operated manually
(hydraulic or electric) or are they 'smart tabs'?
Your outboard probably either has a power trim or a manual trim latch
setup where you have a pin that fits into a slot or hole that puts the
outboard a proper trim angle to the boat.
John C.

planing
 

Those plates came that way. They make great steps to get in and out of the
boat. They are stationary. I just don't see why my boat doesn't plane.
The outdrive does have the manul pin tab, and I am at the farthest (least -
where the shaft is closest to vertical and closest to the boat) setting.
Mike



"jchaplain" wrote in message
...
On Fri, 5 Mar 2004 11:15:22 -0800, "MikeG" wrote:

I have a 17 ft, older trihul. The more throttle I give the more the bow
stands up. I was reading recently about planing. Would my boat be
considered a displacement boat? or is it just set up wrong.

The boat has a Volvo 140 i/o with now trim tab. There are some "trim
plates" on the back.

Also, am I missing some "trim" thing on my outdrive? Something like this

http://www.cabelas.com/cabelas/en/te...item.jhtml?id=
0017147015724a&navAction=jump&navCount=4&indexId=c at21370&podId=0017147&cata
logCode=IE&parentId=cat21370&parentType=index&rid= &cmCat=MainCatcat21276&_DA
RGS=%2Fcabelas%2Fen%2Fcommon%2Fcatalog%2Fitem-link.jhtml.2_A&_DAV=http%3A%2F
%2Fa1460.g.akamai.net%2Ff%2F1460%2F1339%2F6h%2Fwww .cabelas.com%2Fcabelas%2Fe
n%2Fcontent%2FPod%2F01%2F71%2F47%2Fp017147ii01.jpg &hasJS=true

Thanx,
Mike

What are the trim plates on the back? Are they operated manually
(hydraulic or electric) or are they 'smart tabs'?
Your outboard probably either has a power trim or a manual trim latch
setup where you have a pin that fits into a slot or hole that puts the
outboard a proper trim angle to the boat.
John C.

planing
 

The Stingray hydrofoil might be the way to go for you.
Try it. At $50 or so it can't hurt much.
Had one on my last 19 foot boat and it worked great.
John C.

planing
 

On Fri, 05 Mar 2004 19:34:12 GMT, jchaplain wrote:

On Fri, 5 Mar 2004 11:15:22 -0800, "MikeG" wrote:

I have a 17 ft, older trihul. The more throttle I give the more the bow
stands up. I was reading recently about planing. Would my boat be
considered a displacement boat? or is it just set up wrong.

The boat has a Volvo 140 i/o with now trim tab. There are some "trim
plates" on the back.

Also, am I missing some "trim" thing on my outdrive? Something like this
http://www.cabelas.com/cabelas/en/te...jpg&hasJS=true

Thanx,
Mike

What are the trim plates on the back? Are they operated manually
(hydraulic or electric) or are they 'smart tabs'?
Your outboard probably either has a power trim or a manual trim latch
setup where you have a pin that fits into a slot or hole that puts the
outboard a proper trim angle to the boat.
John C.

If 140 horses won't put a 17' boat on plane, then something must be
wrong somewhere. Is the boat water-logged by any chance? Does the boat
have the right propeller? What kind of rpm's are you getting from the
engine at wide open throttle? How much weight do you have in the boat?

Lastly, are you *sure* you're not getting on plane? How fast is the
boat going at top speed?

John H

On the 'Poco Loco' out of Deale, MD
on the beautiful Chesapeake Bay!

planing
 

"MikeG" wrote in message
...
I have a 17 ft, older trihul. The more throttle I give the more the bow
stands up.

This is common, to a point. On a typical runabout, especially one that is
stern heavy, opening the throttle immediatly causes the bow to rise. If you
give it enough throttle it eventually "climbs on top" and starts to plane.
At this point the bow comes down and the boat takes on a more level (though
still slightly bow up) attitude.

Many runabouts have a significant drawback (some might consider it to be a
flaw) that the boat is just impossible to handle at medium slow speeds. At
idle they are fine, and once they are on plane they are fine, but there are
speeds where the bow is up so high that the driver can't see and it simply
doesn't handle. Many times this is not a problem, until you want to pull a
kneeboard or similar water toy that requires you to go 12 MPH.

I was reading recently about planing. Would my boat be
considered a displacement boat?

No, definately not.

or is it just set up wrong.

Maybe.


The boat has a Volvo 140 i/o with now trim tab. There are some "trim
plates" on the back.

Should be okay.


Also, am I missing some "trim" thing on my outdrive? Something like this

I really doubt that these would make a significant difference. They can
make a difference on really light boats, or if you need just a tiny bit of
extra help. It sounds like you need more help than what this would offer.

I noticed your response to another person where you said that the outdrive
is in the position nearest to vertical. It would help to get on plane if
you could actually take the outdrive beyond vertical, so that it tucked up
under the boat slightly. You should also make sure that the outdrive is
lowering to this position when you are in the water. It is possible that
the mechanism that lowers the outdrive isn't allowing to go all the way down
to the pin. Having the outdrive in a partially raised position would
certainly cause what you describe.

The next recommendation would be to move more weight to the front. I have
driven boats where I had to get people to move to the bow in order to get
the boat up on plane! Loading your ice chests, anchors, etc. farther
forward might help out a lot.

You may just be suffering from lack of power. 140 Hp should be enough, but
if this "older" engine is a bit tired it just may lack the get up and go to
get up on plane.

Finally, see if there is a manual adjustment on those trim tabs. If you can
get them to deflect down a bit more they may help lift the boat up on plane.

Good luck
Rod

planing
 

You've had some excellent answers.

Also, check for growth below the waterline. Even a coating of slime really
slows down some boats.

====

Charles T. Low
- remove "UN"
www.boatdocking.com/BDPhoto.html - Photo Contest
www.boatdocking.com
www.ctlow.ca/Trojan26 - my boat

====

"MikeG" wrote in message
...
I have a 17 ft, older trihul. The more throttle I give the more the bow
stands up. I was reading recently about planing. Would my boat be
considered a displacement boat? or is it just set up wrong.

The boat has a Volvo 140 i/o with now trim tab. There are some "trim
plates" on the back.

Also, am I missing some "trim" thing on my outdrive? Something like this

http://www.cabelas.com/cabelas/en/te...jpg&hasJS=true

Thanx,
Mike

planing
 

MikeG wrote:
I have a 17 ft, older trihul. The more throttle I give the more the bow
stands up. I was reading recently about planing. Would my boat be
considered a displacement boat? or is it just set up wrong.

The boat has a Volvo 140 i/o with now trim tab. There are some "trim
plates" on the back.

Also, am I missing some "trim" thing on my outdrive? Something like this
http://www.cabelas.com/cabelas/en/te...jpg&hasJS=true

Thanx,
Mike



Go to a prop place & they'll oft allow you to try different props, try
one with less pitch.

It sounds like your engine can't get enough revs up to make enough HP
at low speed. Try a prop (borrow or second hand just to test) with lots
less pitch if the engine can then run out to high revs from a standing
start, you can be sure you actually have HP available. Then a boat that
size even as stern heavy as it probably is, should get out of the hole.

Once you've established that is the prob. then you can either find out
why over time the engine can no longer generate enough HP low down (can
just be a combination of lots of little things & even a good tune up
won't overcome old age, applies to people too:-)) So maybe then get a
new prop with a lower pitch, this will mean a slightly, very slightly,
lower top speed & more fuel use at cruise but other than that the engine
will have an easier time.

K