How Much Power?
 

What is the minimum recommended HP for a 1978 SeaCraft 18CC? Is 135 Mercury OptiMax to small?

Re: How Much Power?
 

Depends how fast you want to go! I just bought a 1974 20 SF. It has a 125 Force on it. I took it out on Saturday for the first time. It got up on plane fine and went plenty fast for me. I believe it goes around 30. I would guess a 135 on an 18 would be plenty.

Re: How Much Power?
 

115hp is about as low as I would go with that hull....but I've seen them with 90's. The 18' and 20' aren't all that different so you can read on here what people have powered their 20's with and be fairly close in performance numbers to what that same power would do for an 18'.

Re: How Much Power?
 

I had a inline 115 merc on mine and it was Ok but could have used a tad more so your 135 is perfect.

Re: How Much Power?
 

I have an 18 cc that is powered by a Yamaha 150. The power is great but I have always felt it might be too much weight. This is my first Seacraft so I'm not used to the lower water line in the back. With the 150 there is only 3-4 inches from the transom where the engine mounts to the water. If I don't plug the scup drains the back starts to fill with water. Any other 18 or 20' owners have any thoughts? Is this water line normal for the older seacrafts or do I have too much weight with the 150 hp ? I have been thinking about raising the floor level to solve the problem. Any other suggestions appreciated. Thanks

Re: How Much Power?
 

I had a 140 on my 18' at first and then a 130 and it suffered the same problem of being wet if the scuppers were not plugged. When my 20' was redone, the new floor was raised almost 3" to combat this problem (as it was no different than the 18' in this regard).