High bow at slower speeds

[tahoeted]

The only time my boat is level is when I'm going very slow or fast any speed in between and the bow is up and stern is plowing through the water. Any ideas as to what I can do?
I have an inboard outboard (no added foils on the outboard or trim tabs), trim is down all the way.
The boat is a 91' seaswirl 20ft OMC i/o (I/O are both OMC) 5.0L V8
please help - boat and trailer newbie!

 

[This_lil_fishy]

Re: High bow at slower speeds

Pretty normal, some trim tabs might help, but the low speed positioning is more about hull design. Mine tends to get a bit bow high around 25mph...but it cruises nicely at 30-35.....

Ian

 

[Wee Hooker]

Re: High bow at slower speeds

This is quite common with most boats that are designed to plane on top of vs push through the water. At intermediate speeds your pushing a bow wave ahead of you and you don't have enough power to clime over it to get on plane. The wave lifts the bow and pushes the stern down. You can retrim, add a fin, etc but there is no 100% cure that I've ever seen.

 

[tahoeted]

Re: High bow at slower speeds

will the trim tabs or fin really even help?

 

[bear_69cuda]

Re: High bow at slower speeds

I bet these would help.

http://www.iboats.com/Nauticus_SX_S...7619583--**********.053654086--view_id.352485

I'm installing them on my boat, and have heard nothing short of incredible things about them!

 

[woosterken]

Re: High bow at slower speeds

check this out ,very good article on trim.........
http://www.clubmarine.com.au/internet/clubmarine.nsf/docs/MG19-2+Technical

hope it helps

woosterken

 

[Ned L]

Re: High bow at slower speeds

What you are experiencing is a 'fact of life' so to speak, inboard/outboards (IO's) are often the worst offenders as there is so much weight right at the transom. Things can be reduced some with trim tabs, shifting weight, trimming the outdrive, etc, but you will not get the boat to ride 'level' at those 'in-between' speeds. .

 

[metriccrescentwrench]

Re: High bow at slower speeds

What you are experiencing is a 'fact of life' so to speak, inboard/outboards (IO's) are often the worst offenders as there is so much weight right at the transom.

Also be aware of the fact that at these speeds you're throwing the largest wake that is physically possible for your boat. I can't begin to count the number of people with large I/O boats who have driven by when I'm fishing with my anchor down and slow to plowing speed, apparently thinking they've just done me a great favor. They'll smile and wave, it's been hard not to give them the universal sign of cheer and goodwill.

 

[Tim Frank]

Re: High bow at slower speeds

They'll smile and wave, it's been hard not to give them the universal sign of cheer and goodwill.

They'd just think you were telling them that they were "number one"...

 

[AngelC]

Re: High bow at slower speeds

will the trim tabs or fin really even help?

Trim tabs will most definately help you out. I also have a 5.0l Sx drive on a 20footer. I did have the same problem, so...to resolve it I changed out the prop from a 3 to 4 blade for more stern lift and added a set of trim tabs that I bought here from iboats and I was blessed with spectacular results and I'm sure you would be happy too. Now bow is down and stern is up at very low speeds. However I don't believe you can add a fin with the tabs, I think it's one or the other or you will not get the results your looking for. But I could be wrong check with the fellows here, they will have an answer.

Good Luck

 

[tahoeted]

Re: High bow at slower speeds

Thanks everyone. I was switching to a 4 blade prop and will look into the trim tabs. I will also keep in mind of trying not to plow that big wake towards the anchored boats.

Thanks!