prop shaft height on 38 TG IV SSM rerig
11-07-2012, 10:20 AM
#12
Registered
First, think of the notch as an 8" box. Now your adding another box to that which is not a bad thing, but remember the farther back you go without going up is putting the prop in cleaner water but in affect(deeper).
Mercury boxes typically have 3 sets of holes. Neutral 1" up and 1" down. Your "U"joints in the half shaft can take that movement. I would set it at 1" above in neutral position. That way you can go up or down an inch without spacers. 2" above is as high as you'll ever go. And as Kvogt said down is alittle easier.
Mercury boxes typically have 3 sets of holes. Neutral 1" up and 1" down. Your "U"joints in the half shaft can take that movement. I would set it at 1" above in neutral position. That way you can go up or down an inch without spacers. 2" above is as high as you'll ever go. And as Kvogt said down is alittle easier.
11-07-2012, 01:37 PM
#13
Platinum Member
Platinum Member
You will probably end up at least 1 inch below the hull.....especially with the lower HP. Two inches below may even work better with #4's. This will help with leverage to carry the bow. In my experience with #6 drives on a Kevlar Gun, 1" below the hull offered the best all around performance....even with 900 HP. Level with the hull worked better when running over 85 mph. The straight bottom Cigs always seem to like more prop depth.
The next problem will be getting on plane with #4's, since they don't trim in (tuck) nearly as much as a #6. That 1" below the hull will probably turn out to be very aggressive when trying to get out the hole.
The next problem will be getting on plane with #4's, since they don't trim in (tuck) nearly as much as a #6. That 1" below the hull will probably turn out to be very aggressive when trying to get out the hole.
Last edited by CignificantOther; 11-08-2012 at 04:04 PM.
11-07-2012, 05:41 PM
#16
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I think it will be difficult to get on plane with 4 blade props. My brother did a flat deck (no notch) with 4s and boxes and put the drive shaft about a 1/2 inch above the bottom. The boat does a big burnout with 5 blade, 17.5 diameter props. For an all around boat I would go around 1.5 below the bottom. At the speeds your going to see with 800s I don't think it will hurt you any.
But you can always space down, going up is tough.
But you can always space down, going up is tough.
Any opinions on spinning the props in instead of out? I plan on trying the spacers first if that gets me on plane better I`m good with that.
11-07-2012, 06:57 PM
#17
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Thread Starter
Can you enlighten me on how you're set up now? Just out of curiousity?
11-07-2012, 07:23 PM
#18
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icdedppl bought the boat from kvogt's brother.
icdedppl food for thought on your boat getting on plane... i rigged a fountian this year that has a notched transom. speedmaster #4s. previously the props ran about 1/4 above bottom of boat without boxes. was horrible to get on plane. took about a week lol. i put boxes on the boat and we set the prop about 1 inch below. boat handled like a ferrari and by 3k rpm the boat walks right on plane. scrubbed 1-2 mph off the top end but the stability on the top end and ease of getting on plane was worth the loss on the top end all day long
icdedppl food for thought on your boat getting on plane... i rigged a fountian this year that has a notched transom. speedmaster #4s. previously the props ran about 1/4 above bottom of boat without boxes. was horrible to get on plane. took about a week lol. i put boxes on the boat and we set the prop about 1 inch below. boat handled like a ferrari and by 3k rpm the boat walks right on plane. scrubbed 1-2 mph off the top end but the stability on the top end and ease of getting on plane was worth the loss on the top end all day long
11-07-2012, 09:00 PM
#19
Registered
^^^^ Thats great news, yes it takes a week to get on plane as is 
I think the spacers should make a nice improvement,
thank you.
I think the spacers should make a nice improvement,
thank you.
