Engine heights with twins

[PORT]

I have a 21' Sonic (shallow vee) that I put twin 2.4 EFI offshores on, the engines are 25" on center. Boat has 15" pad and my lower units hit on 7.5" of each side of the pad. I have a quick question, when you are measuring/setting the height of the tip of the bullet of the nose cones do you set them in relation to the pad or to the bottom of the boat where the nose cones intersect? Right now the lower units are 1.25" below bottom, which makes it 1.125" above the pad. Previously I had the lowers .25" below bottom, which made it 2.125" above pad. When I did this the MPH and RPMs didn't change.

Pad or angle of bottom of hull where lowers follow?


see pic

[PORT]

Pic of Sonic

[Frank Molé]

if u need lift go down a half at a time

[PORT]

During testing this morning I dropped it an inch and nothing. I couldn't go any further down with the jackplates so this afternoon I just dropped the motors two bolt holes (1.5"). This puts me a 1/4" below the pad. This better work or I am in trouble, no more engine holes to go down and my stainless lines for the trim are sitting on the transom already. :eek:

I have a good feeling that tomorrow morning I am going to be smiling or I will be drinking alot :D

[Frank Molé]

did it work:confused: that might need a inch below:eek:

[Toffen]

Hi!

I run my twins approx 1 inch below the bottom. When you measure you should measure in relation to the bottom and not the notch. However, the nothed transom allows you to run the engines highes as the water hits the props higher.

Merc hi performance reccommends even with the bottom if running with a sportmaster lower unit and 90 mph. I would test between 1 inch below and even with the bottom.

The only remark I have is that the engines seems to be a little far apart. I run them 19 inches senter senter. As closer you get, the better bowlift and lower gravity. I would mount the engines closer if possible.

Cheeers! Toffen G