Question about Trim

[cheejudo]

Is there a article, diagram or something that can explain Trim to me.. I'd like to know how far down i need to trim for best cruising/fast moving/goin real slow... i remember seeing one before

 

[veritas honus]

Re: Question about Trim

Not familiar with any article or diagram. When you trim all the way down, your prop thrust is angled downward, forcing the stern upward and the bow downward. Trimming up has the opposite effect. Water conditions and speed will dictate the best trim angle. This of course will usually not remain constant for very long. Experiment with the use and effect of trim on performance. Pay attention to how it affects RPM's as well as porpoising and how your boat planes at different trim angles. Have fun with it. Learn by experience; but by all means learn all you can about the physics and theory of trim to help give you a better understanding of what and why...

I may not have explained it very well, but you'll pick it up really quickly with use. Hope I've helped.

 

[blifsey]

Re: Question about Trim

Here is how I've learned to use trim...maybe totally wrong but has worked for 12 years or so.
- trim down - getting on plane (starting off), idling along in no wake (putting trim down when approaching no wake zone at speed helps slow down due to drag).
- trimming up - once on plane, start trimming up until one of 2 things happen depending on boat and load in it. 1) boat begins to porpoise (bow bouncing up/down that isn't caused by waves/wakes) or 2) prop begins "slipping" and RPMs jump up without any change in speed

Choppy water - if water is chopped up pretty good, trimming down can help soften the hits by bringing bow down and hitting wake with the deeper V of the bow

Water Sports - I watch wake and adjust trim to get best wake for watersport we are doing. For example, wakeboarder may want bigger wake while skier wants flatter wake. Once running at desired speed, I'll adjust trim until wake is best. This usually requires throttle adjustment to maintain desired speed.

Shallow water idle speed and loading on trailer - trim up enough to keep lower unit from hitting bottom

 

[cheejudo]

Re: Question about Trim

so from what i understand i need to trim all the way down to get on plane, and then adjust it up. maaybe it was because it was my first trip, but last time when i gave it throttle it seemed like the bow come up real high before it settled back down... kind of unnerving!

 

[blifsey]

Re: Question about Trim

Yes, trim all the way down when getting on plane. And yes, the bow can point sky high if trimmed up when you hit throttle. Even trimmed down, bow can still point skyward if load in boat is too much in back. With our previous Glastron, it never was much of an issue because they have a "helm forward" design. With current Tidewater, we had 6 on boat and all were behind console. When getting on plane 2 or 3 had to move forward of console. Also, if the bow is kept down it will get on plane much faster/easier.

 

[veritas honus]

Re: Question about Trim

cheejudo,

Try this, When you're ready to get on plane, trim down and hammer the throttle down... "pedal to the metal" so to speak. Make sure your passangers are ready as well as you. Your bow will come up high briefly, and settle down on plane rather quickly. You don't have to wait for the bow to come all the way down to trim up. You can gradually ease the trim up in unisyn with the leveling off of the bow. This is one of the things you'll have fun becoming accustomed to. "Play" with the trim at different speeds and during varying water conditions. Pay attention to how it affects your handling and stability on the water. Everything is a learning experience. Have fun with it. The more you do this, the sooner you'll find yourself adjusting the trim as you throttle up and down to compensate for, and better handle varying water conditions without even thinking about it. This is why there is a trim switch on the throttle. The first time you find yourself doing this, you'll realize that you've been doing it for a little while and didn't even notice. It'll make you smile.

 

[dozerII]

Re: Question about Trim

Here ia link to a real good article on trim. http://www.clubmarine.com.au/internet/clubmarine.nsf/docs/mg19-2+technical
Glen

 

[DeviledAvs]

Re: Question about Trim

Hi all, this is my first post on iboats.com, so please forgive me if I sound like a rookie - after all, I am. My wife & I just took delivery of a 2011 Tahoe Q5SF with a 4.3L MerCruiser and an Alpha One Stern Drive. Whereas we've both spent a lot of time on the water with friends, this is the first boat we've actually owned and because I've seen motors both with and without a Hydrofoil Stabilizer, I was wondering if I should consider installing one on our boat or should I simply play with the trim as described above... or both? We plan on taking it out tomorrow or Monday without a Hydrofoil Stabilizer, but I wanted some experienced advice to go along with my "testing" this weekend. Any insight would be greatly appreciated.

 

[Joshua Nichols]

Re: Question about Trim

Hi all, this is my first post on iboats.com, so please forgive me if I sound like a rookie - after all, I am. My wife & I just took delivery of a 2011 Tahoe Q5SF with a 4.3L MerCruiser and an Alpha One Stern Drive. Whereas we've both spent a lot of time on the water with friends, this is the first boat we've actually owned and because I've seen motors both with and without a Hydrofoil Stabilizer, I was wondering if I should consider installing one on our boat or should I simply play with the trim as described above... or both? We plan on taking it out tomorrow or Monday without a Hydrofoil Stabilizer, but I wanted some experienced advice to go along with my "testing" this weekend. Any insight would be greatly appreciated.

Start a thread and ask the question... That is a favorite arguement on here lol.. You will get a ton of replies

 

[DeviledAvs]

Re: Question about Trim

Start a thread and ask the question... That is a favorite arguement on here lol.. You will get a ton of replies

Thanks, I just cut and pasted to a new thread... I kinda figured I'd get a mixed bag of replies, but I'm looking forward to what everyone else thinks.