2005 16' Duroboat won't trim up

Nicoya

Cadet
Joined
Jan 28, 2010
Messages
16
Hello.
I have a 2005 16W with a 2018 30hp suzuki 4 stroke outboard with remote steering.

I can get the boat to plane without any issues, but the bow trims down right away.

I try to trim up but my propeller starts cavitating. Therefore the boat won't trim up. The motor trims works fine.

I can get up to 20mph but the bow digs in at times.

I bought the boat about 5 years. The boat had an older 2 stroke engine and it had the same issue.

I looked into the Suzuki specs and the 30 hp only comes with a 20in shaft. The motor mount clamps are all the way touching the top of the transom. According to the Duroboat spec sheet the 16W has a 20 inch transom.

I placed a straight edge on the keel and the anti cavitation plate is .75 inches below the keel. The motor specs says it should be 0-1".

Please provide some advice.
I've been scratching my head for a while now.

Thank you.
 

Stinnett21

Chief Petty Officer
Joined
Jun 24, 2012
Messages
507
Please describe your boat better. I don't know what a 16W is. My first thought is your boat has a hook in it. Sight down the keel from the transom. Is it straight or is it bent?
 

Stinnett21

Chief Petty Officer
Joined
Jun 24, 2012
Messages
507
Sorry. See it in your title now. Nice boat. Just wondering if the bottom is straight.
 

JimS123

Fleet Admiral
Joined
Jul 27, 2007
Messages
8,188
It may have been built straight, but improper storage may have deformed the hull.

You need to crawl under the boat and make a close inspection with a long straight edge.

What is the maximum rated HP for the boat?
 

Nicoya

Cadet
Joined
Jan 28, 2010
Messages
16
Thank you for the response.
Yeah the keel is straight.
The max hp is 45.
They probably used the weight of a 2 stroke 45 hp motor. I have a 30hp 4 stroke now which weights 159lbs. I had a 40hp 2 stroke which was 187lbs. The problem happened with the old motor too. I'm just tired of plowing in the water.
 

JimS123

Fleet Admiral
Joined
Jul 27, 2007
Messages
8,188
If possible, move some weight aft.

Also, you might try a set of fixed trim tabs. That may sound counter-intuitive, but you might be surprised. I had a boat once that wouldn't accept ANY trim. With the tabs adjusted slightly downward it would take FULL trim. Granted, my problem was porpoising.

Maybe you should explain exactly what you are experiencing.
 

Nicoya

Cadet
Joined
Jan 28, 2010
Messages
16
Thanks for the response.
I've tried to put more weight aft, my 220lbs brother. No chage, I can't trim.
Here is an overview of the issue...
I trim up the motor and give it throttle. The bow points up, and I trim down so the boat gets on plane. After being on plane for a few seconds the bow drops. I then try to trim up and the prop starts cavitatjng. Therefore the boats does not trim up.
I hope this describes my issue a bit better.
Thank you for the help.
 

JimS123

Fleet Admiral
Joined
Jul 27, 2007
Messages
8,188
What do you mean by cavitating? From the pics, it looks like the motor is too low, but the picture angle isn't right.

Take a pic from behind the motor, showing exactly where the anti-ventilation plate is in line with the keel.

Looks like a real nice rig. We'll get her figured out!
 

Nicoya

Cadet
Joined
Jan 28, 2010
Messages
16
Thank you.
Cavitating-as I try to trim up I hear the propeller as is about to come out of the water.
I'll post pictures of the anticavitating plate and keel.
Thank you.
 

Nicoya

Cadet
Joined
Jan 28, 2010
Messages
16
The two pictures above show that there is a slight cave-in portion. This probably occurred since the previous owner had a bad bunk.
Could this be the cause of not being able to trim?
 
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