motor height and placement

[new shade tree boat mech.]

I have a 1959 fastwin on a i think its a 16ft v bot. i have a couple questions. i dont know all the correct termemnolgy. originally when my dad bought the boat the transom dipped down in the back and the 18 hp was a long shaft i was very young and i think it made the front lift wat out of the water. since then my brother repalced the board on the transom and made the motor sit higher mainly to not hit rocks and logs in the river. just wondering the correct hight it should be?? and also there are three adjustment on the motor by the lower motor mounts dont know what there for looks like maybe a height adjustment or some type of a trim adjuastment?? maybe some pics or diagram would be helpful. lastly how could i tell what kind of boat it is?

 

[new shade tree boat mech.]

Re: motor height and placement

I have a 1959 fastwin on a i think its a 16ft v bot. i have a couple questions. i dont know all the correct termemnolgy. originally when my dad bought the boat the transom dipped down in the back and the 18 hp was a long shaft i was very young and i think it made the front lift wat out of the water. since then my brother repalced the board on the transom and made the motor sit higher mainly to not hit rocks and logs in the river. just wondering the correct hight it should be?? and also there are three adjustment on the motor by the lower motor mounts dont know what there for looks like maybe a height adjustment or some type of a trim adjuastment?? maybe some pics or diagram would be helpful. lastly how could i tell what kind of boat it is?

ya i was looking at some other posts dont know keel and anti ventilation plate and anti cavitation ????

 

[steelespike]

Re: motor height and placement

The anti vent plate is the plate just above the prop.Ventilation is when the prop sucks air and loses it grip on the water.motor revs up bvoat slows.Cavitation used to be used to describe it
but cavitation is different and is what happens when the water boils in the low pressure areas of the prop.Usually doesn't affect operation.It may leave marks on the prop.
A keel is the backbone of the boat the external portion is visable down the center of the bottom.The notches are trim to help get the ideal boat trim when under way.Prop trimmed away from boat raises the bow prop closer to boat lowers bow.Generally will run faster trimmed bow up.
But not too extreme.With the old style gearcase (where prop is attached) the antivent plate
should run about 1 or 2 inches below the bottom.You can set it up so you could raise it more
by using a jackplate. (a device attached to the transom allowing easy adjustment of motor height)you can adjust the height over a broader range.
If you measure the motor from where it rests on a transom to the antivent plate
I think you will find it is about 21 or 22 inches.

 

[roughneck1455]

Re: motor height and placement

When measuring the cavitation plate to the bottom of the boat, should the motor be trimmed all the way down or what setting should it be on a manual trim?

 

[JimS123]

Re: motor height and placement

Transom height for a short shaft should be 15". A long shaft is 20". Its not a good idea to arbitrarily change "board height" to some other number. Your transom should be one or the other.

Post the model number of your motor and we can look it up and tell you what you have. A pic would confirm it.

Your boat registration will tell you what kind it is. If you don't have that, there might be a label on the boat somewhere. In the absense of all data, a pic online would probably get you an answer.

Trim of an outboard is largely an empirical determination, based on the components and condition of the boat. In other words, trial and error. Put it in the #1 position and run the boat. Then try the other positions. Pick the one that suits you best.

As far as the other words that you don't know, a 2 second google search will give a pretty clear definition from an online encyclopedia (that is if you don't have a dictionary at home).
http://en.wikipedia.org/wiki/Keel