X Dimension on a Flat Deck
 

I am going to upgrade from No 3 drives to No 5 drives . I am looking for input from any of you that have had experience with these drives on a non notch Cig without boxes. My initial research would lead me to run the prop shaft 2 inches below the running surface that way I could still space it down 3 inches if planning is a problem. My concern is 2 inches below to much or do these drives work more like a 6 drive and therefore you would run them level with the running surface.
In any event any input would be appreciated.
Thanks Rick G.

Icedppl just spaced his 4's down. I think 2" below with 17.5" props will work very well if my understanding is correct. The higher you go the more critical and sensitive prop selection becomes.

Template
 

I've got a nice template we made to cut the transom for a #5 It's very precise, 1/4 luan coated in resin. $25 plus shipping if you need it. I always cut the tiller arm off, leaving the splined end of the arm on the transom assembly shaft. This makes one less hole in the transom and I never use the internal tiller arms anyway. It is a much cleaner installation.

I`m on boxes but after the 2" spacers its about a 1" below, if I`m measuring right

Thanks O.C. I actually created a template from quarter inch plate steel with fixtures to insure the mounting holes are drilled square to the transom.
ICDEDPPL thanks , have you run the boat with the spacers if so how does it plane .
Rick

I`ll know more once the snow melts
:cartman:

ICDEDPPL ( okay what does that stand for) . I had a long talk with Phil lipship about X dimension on our boats what a great guy . The first thing he said was that without a cavatation plate plaining will always be a challenge. On X dimension he suggested that i put a notch in my hull which I am going to do over the next couple of weeks. The fact you have boxes gets you to the same place. Here is the kicker he suggested that I start with the prop shaft 4 inches beloww the planing surface. Which is a little lower than I would have thought . But given his experience with cigarette I am going to take his advice . The 5's I have , have a 2 inch spacer that has a cav plate welded on , so I will be setting hieght some where in the middle so I can space up or down from the 4 inch starting point. He also thought that I start with a 5 blade prop and possibly might need a 6 blade. I will keep you posted .
Rick G.

I SEE DEAD PEOPLE :lolhit:

Good info but there goes your rooster :bunnydance:
I think you have a solid plan there, with the drives that deep it should jump on plane like a Baja.

ICDEDPPL , I boat with 3 to 4 passengers in the boat all the time. I went through the 5000 rpm burn out getting on plane with my 43 scarab and it was a royal pain in the ass and hard on the equipment . I would love to keep the rooster but these things are expensive enough when s@ck doesn't break.
Rick.

Hey Rick. My buddy's flatdecks with 3's and 3A's are about 3.5-4" below the bottom. Planing with 4 blades is no problem. They were rigged this way 20-25 years ago, when 3 blades were the norm.

Personally, I don't think I would cut the hull for a notch. I'd prefer boxes. If boxes aren't in the cards, I think I would start with 2.5" below, and add spacers to suit if needed.

A problem with the IV and V drives, is the drives don't tuck in as far as say a #6, or TRS. When fully trimmed down, they just don't have much negative angle. On my boat, with iv's, I have to have the tabs all the way down to plane, or no cigar. I would like to add 380 tabs, to give the transom a little more lift when planing.

Wish I had the time to make a wedge plate, like some of the arnesons had, between the transom assembly and the transom. To help get some extra negative angle on the drives when tucked in. My buddys 38 Fountain with #6's, and 4 blades, has his shafts 2" higher than mine, but yet planes like a ski boat with the 6's.