84 Excalibur 27 changing to a Bravo
#1
Does any one have any tips if they have tried this? I like the idea of no transmission and moving the engine back. Any idea of where we should set the X. If I leave it to the guys down here I will be buying a lot of spacers
Cheers
Andy
Cheers
Andy
#2
I'm in the middle of my changeover to bravos (it's taking me entirely too long).
Anyway my 1984 31 ' Excalibur had merc II tranys with the TRS.
The merc trans is pretty short so the engine is only moving back about 4 inches.
The prop depth back when these boats was pretty deep. With todays 4 & 5 blade props you can handle a pretty high X. It all depends on how patient you are about planing, right?
The bravo unit is around 2 inches shorter than the TRS (I think a little more than 2 like 2-1/4). So leaving your engine centerline at the same height will raise your prop height that amount.
I never measured my prop height before I took everything apart, but looking at my stock X dimension of 18.5 my prop height was over 5 inches deep.
I moved my engine centerline up another 1/2 inch. I would have gone a full inch but I had hatch issues. I think I'll end up around 2-1/2 inches below the running surface.
My boat has twins, that's what I did, and it hasn't hit the water yet. If I have trouble planing I'll throw spacers at it.
I don't know if that helps or not.
Dan
Anyway my 1984 31 ' Excalibur had merc II tranys with the TRS.
The merc trans is pretty short so the engine is only moving back about 4 inches.
The prop depth back when these boats was pretty deep. With todays 4 & 5 blade props you can handle a pretty high X. It all depends on how patient you are about planing, right?
The bravo unit is around 2 inches shorter than the TRS (I think a little more than 2 like 2-1/4). So leaving your engine centerline at the same height will raise your prop height that amount.
I never measured my prop height before I took everything apart, but looking at my stock X dimension of 18.5 my prop height was over 5 inches deep.
I moved my engine centerline up another 1/2 inch. I would have gone a full inch but I had hatch issues. I think I'll end up around 2-1/2 inches below the running surface.
My boat has twins, that's what I did, and it hasn't hit the water yet. If I have trouble planing I'll throw spacers at it.
I don't know if that helps or not.
Dan
#3
Registered

Joined: Mar 2003
Posts: 3,074
Likes: 79
From: Fort Worth, TX
I also made the switch. Zanie has given good info here. I set my X at 18" with a 34" centerline. This put my shafts 4" in the water. I am running extension boxes also with Imco shorty drives. I have no problem at all planning no matter if i am spinning the props in or out. I should have gone with a 19" X.
The 27's lean under load from what I have seen. It seems like getting the prop higher and spinning it faster would even the boat out. Good luck. Post some pictures.
The 27's lean under load from what I have seen. It seems like getting the prop higher and spinning it faster would even the boat out. Good luck. Post some pictures.
#4
Registered

Joined: Nov 2005
Posts: 1,840
Likes: 37
From: south jersey
Do the bravo gimble and transom assemblies bolt over the old trs hole, or do you have to close the transom and cut a new hole? I know when going from alpha to bravo all you do is drill a couple more holes and it bolts right up!
#6
We filled in the inside today. The job was pretty easy as I had someone else do it for me
we will be filling in the outside tomorrow and then cut the hole early next week. I want to relocate all of the trim pumps(4) to the midships bulkhead to help with the weight transfer. I am a little nervous about moving the engine back that far. The boat was very level the way that it was set up before we touched it.
Cheers,
Andy
we will be filling in the outside tomorrow and then cut the hole early next week. I want to relocate all of the trim pumps(4) to the midships bulkhead to help with the weight transfer. I am a little nervous about moving the engine back that far. The boat was very level the way that it was set up before we touched it.Cheers,
Andy




