Trimming You Motor For Max Speed

[Guest johblow]

Gidday all. Can someone share some pearls of wisdom about trimming motor tilt for max speed, with a varying load location and size?

I have a 5m tinnie with forward controls/bucket seats powered by a 25, and must admitt that i really dont know any concrete info about adjusting the tilt. Its a manual operation in my case, so trial and error is not simple.

Is it as simple as keeping the leg as vertical as possible? Where should the center of mass of the boat and load be? Should it be placed such that the boat planes as close to horizontal as possible.

Dumb questions i know, but hey, im dumb!

Cheers,

Jon

[numbers]

Gidday all. Can someone share some pearls of wisdom about trimming motor tilt for max speed, with a varying load location and size?

I have a 5m tinnie with forward controls/bucket seats powered by a 25, and must admitt that i really dont know any concrete info about adjusting the tilt. Its a manual operation in my case, so trial and error is not simple.

Is it as simple as keeping the leg as vertical as possible? Where should the center of mass of the boat and load be? Should it be placed such that the boat planes as close to horizontal as possible.

Dumb questions i know, but hey, im dumb!

Cheers,

Jon

Jon

Try going for a drive & take another person with you (take someone hefty).

get them to sit up front with you & whilst driving along (on the plane) get them to move right down the back. You should feel a difference in the boat's behaviour (steering & maybe even tyhe revs might pick up a bit). This will give you an idea of how distributing the weight will help.

Ideally you should have the motor trimmed "out" (up) as far as possible (just before it cavitates). This is easy to do with power tilt/trim, however as yours is all manual, you run the risk of cavitating in turns & you might also cavitate in rough stuff.

My skiing background says put EVERYTHING down the back (when water comses over the transom, move something froward ) & when on the plane trim right out. This will obviously cause a few issues in your boat - 1. you may have trouble getting onto the plane (the motor may not have enought to get on the plane) and 2. the boat could end up at an uncomfortable angle to fish out of & may become unstable.

I hope i have given you something to think about in relation to solving your problem. I don't believe there is any hard & fast answer, so i thought i'd share my thoughts & let you have fun working it out (another excuse to take the boat out!!!!!).

Cheers

Numbers

[Grantm]

I would say trial and error. Dont try and make it plane horizontal cause it will load your motor up too much. If its too high at the front it may tend to 'porpoise'

Dont worry about the angle of the leg being vertical because at speed it will always sit roughly the same. Its the boat that will change.

A correctly trimmed boat should, as a rule of thumb, sit just a little nose high but not too much. You owners manual would have some good pic if youve got one if not let me know and we can post some pics.

[Coast_Bloke]

Go HERE and read through it. There is a section on trimming.

[mrsswordfisherman]

Thank you for pointing us to that site Coast_Bloke

Cheers mrsswordfisherman

[Guest johblow]

Thanks for all that food for thought people - its much appreciated

[domza]

Gidday all. Can someone share some pearls of wisdom about trimming motor tilt for max speed, with a varying load location and size?

I have a 5m tinnie with forward controls/bucket seats powered by a 25, and must admitt that i really dont know any concrete info about adjusting the tilt. Its a manual operation in my case, so trial and error is not simple.

Is it as simple as keeping the leg as vertical as possible? Where should the center of mass of the boat and load be? Should it be placed such that the boat planes as close to horizontal as possible.

Dumb questions i know, but hey, im dumb!

Cheers,

Jon

A 5meter boat powered by 25horsepower?? am i reading that right??

Our 5 metre fibreglass halfcabin powered by 80hp merc is at the perfect tilt when the motor is tilted all the way down, so i dont have to really look for a sweet spot everytime..

[Guest johblow]

A 5meter boat powered by 25horsepower?? am i reading that right??

Yep, thats right. It gets along well. Its a tinnie, so its pretty light. With only me in it i give my mates half cabin with a 65HP a good run for its money. Im not sure wether you think its too small or too big? Ive seen other boats the same size and shape with larger motors :-)