Phantom 25 and its new Verado 350 sci
11-21-2010, 03:28 AM
#1
Registered
Thread Starter
Phantom 25 and its new Verado 350 sci
Hi,
I have decided to order a new Verado 350 sci for my ol' Phantom 25. The two Merc 2.5 EFI SS engines and lots of equipment left for UK in a Ford Mondeo (!) yesterday.
Reconfiguration of the transom starts in December. New Livorsi Vantage instruments, full power assisted steering, new cockpit setup, Bobs HD 4 inch jackplate, etc - all to be mounted soon. I will post pictures when we start up.
Lets hope the new Poseidon gearcase will be fast Goal is 81-83 mph.
Cheeers, Toffen
I have decided to order a new Verado 350 sci for my ol' Phantom 25. The two Merc 2.5 EFI SS engines and lots of equipment left for UK in a Ford Mondeo (!) yesterday.
Reconfiguration of the transom starts in December. New Livorsi Vantage instruments, full power assisted steering, new cockpit setup, Bobs HD 4 inch jackplate, etc - all to be mounted soon. I will post pictures when we start up.
Lets hope the new Poseidon gearcase will be fast Goal is 81-83 mph.
Cheeers, Toffen
Platinum Member
08-24-2011, 05:08 PM
#3
Registered
Thread Starter
Hi!
Here is the video in HD http://vimeo.com/28111717
We first cruised in 60 mph with jackplate all way down, thats the reason for the spray behind the transom. It looks like rostertail, but it is not. I have looked behind I have tested with jackplate one inch higher, but I loose speed. From 2,25 mins the speed goes up to 70 mph + and I jacked up the engine 1,5 inches. The last part is 80 mph with a great flow and angle in the boat. I am spinning a reworked Rev4 25 to 6,400/6500 rpms. Lots of lift in the prop.
But then it was over as we suddenly approached inshore. Later in the week we will test the speed on my favorite Fjord. There I normally get 2-3 mph faster speed than outside my hometown.
Cheeers, Toffen
Here is the video in HD http://vimeo.com/28111717
We first cruised in 60 mph with jackplate all way down, thats the reason for the spray behind the transom. It looks like rostertail, but it is not. I have looked behind I have tested with jackplate one inch higher, but I loose speed. From 2,25 mins the speed goes up to 70 mph + and I jacked up the engine 1,5 inches. The last part is 80 mph with a great flow and angle in the boat. I am spinning a reworked Rev4 25 to 6,400/6500 rpms. Lots of lift in the prop.
But then it was over as we suddenly approached inshore. Later in the week we will test the speed on my favorite Fjord. There I normally get 2-3 mph faster speed than outside my hometown.
Cheeers, Toffen
08-26-2011, 08:56 AM
#7
Registered
Thread Starter
Hi!
Thanks
The film boat is a motion 25 with twin 250 xs engines. Phantom 25 is a UK design by Steve Baker. The 25 was used in the offshore circuit in mid 80 ties, and also raced endurance races around UK (!). typically equipped with 2xXR2. I did have 2x2.5 efi for some years, but this new setup is just as fun + 1/4 in cost annually...
The only drawback is the gearcase which is bigger than normal cases. Extra drag and not that happy about high transom heights. However, its very very strong, so I easily drop 1-2 mph to secure a season of fun
cheers Toffen
Thanks
The film boat is a motion 25 with twin 250 xs engines. Phantom 25 is a UK design by Steve Baker. The 25 was used in the offshore circuit in mid 80 ties, and also raced endurance races around UK (!). typically equipped with 2xXR2. I did have 2x2.5 efi for some years, but this new setup is just as fun + 1/4 in cost annually...The only drawback is the gearcase which is bigger than normal cases. Extra drag and not that happy about high transom heights. However, its very very strong, so I easily drop 1-2 mph to secure a season of fun
cheers Toffen
08-26-2011, 08:33 PM
#8
Registered
Congrats on getting it up and running. Looks great and I fully understand wanting to get away from twins. I'm looking at single outboard boat as a second boat for economys sake. Enjoy and keep us posted. Bob
08-29-2011, 03:48 PM
#9
Registered
Thread Starter
Hi!
I will shorten the exhaust tube of the Rev4 this week. I have been told that this should give me approx. 1 mph extra.
There is no need of PVS on my 350 sci as the torque turns everything. However, I wonder if the open PVS holes steal speed? I have no problem turning a prop with all PVS holes plugged. Some say plugging all is faster, other say that no plugs at all are faster. I will test to be sure. Any experiences here?
I have also expererienced a sort of blow out with the gearcase caused of what I think is a combination of high transom height, gearcase crabbing and too much positive trim. It was like being hit by a small wave from starboard. I tested the positiv trim on flat water the other day with the Rev4. And went too high. Normally the rpm increase if you overtrim, but here you got the starboard hit..
I also experienced that the Mirage Plus prop did not like to semisurf. If too high, it lifted the transom and the boat moved little sidewise.... I did not experience this with the torquemaster gearcase and Promax 300 SVS, but the speed was lower then.
Maybe the bigger 5,44 is more sensitive to high transom height than the torquemaster 4,88 case. And it start acting weird. Thats the only down side I can find for the moment about the 350 sci. I still learning about the new setup, so I am sure I will hit the sweet spot in the end.
Cheeers, Toffen
I will shorten the exhaust tube of the Rev4 this week. I have been told that this should give me approx. 1 mph extra.
There is no need of PVS on my 350 sci as the torque turns everything. However, I wonder if the open PVS holes steal speed? I have no problem turning a prop with all PVS holes plugged. Some say plugging all is faster, other say that no plugs at all are faster. I will test to be sure. Any experiences here?
I have also expererienced a sort of blow out with the gearcase caused of what I think is a combination of high transom height, gearcase crabbing and too much positive trim. It was like being hit by a small wave from starboard. I tested the positiv trim on flat water the other day with the Rev4. And went too high. Normally the rpm increase if you overtrim, but here you got the starboard hit..
I also experienced that the Mirage Plus prop did not like to semisurf. If too high, it lifted the transom and the boat moved little sidewise.... I did not experience this with the torquemaster gearcase and Promax 300 SVS, but the speed was lower then.
Maybe the bigger 5,44 is more sensitive to high transom height than the torquemaster 4,88 case. And it start acting weird. Thats the only down side I can find for the moment about the 350 sci. I still learning about the new setup, so I am sure I will hit the sweet spot in the end.
Cheeers, Toffen
08-29-2011, 07:35 PM
#10
Registered
"Blowout" can happen in smooth water too, it is a by-product of the hole being punched in the water by the gearcase big enough to fit the prop through. it sounds like what your experiencing is cavitating. Prop hight too high or too much trim. a prop with more blade area can fix it. the cure for blowout is in the nosecone shape mostly.
