Twin Promax 300 - how close?
06-10-2003, 05:06 PM
#1
Gold Member
Gold MemberThread Starter
Twin Promax 300 - how close?
Hi!
I know I have been into this before, but pls help.
I have made some serious measurements, and I can get two Promax 300 on my Phantom 25 (its only 5,5 feet wide) if I mount them 21 - 21,5 inches senter to senter. This mean 1 - 1,5 inches between the cowlings. I can not wider due to the stringer system at the transom. Is this possible?
I also need to convert to 15 inches midsections, as the engines will be mounted direct on the transom. Is this possible to get hold of?
Its reccommended to rise the engine 6-8 inches with a twin installation according to Merc Hi Perf. Any ideas of propheight?
Cheeers, Toffen - Norway
I know I have been into this before, but pls help.
I have made some serious measurements, and I can get two Promax 300 on my Phantom 25 (its only 5,5 feet wide) if I mount them 21 - 21,5 inches senter to senter. This mean 1 - 1,5 inches between the cowlings. I can not wider due to the stringer system at the transom. Is this possible?
I also need to convert to 15 inches midsections, as the engines will be mounted direct on the transom. Is this possible to get hold of?
Its reccommended to rise the engine 6-8 inches with a twin installation according to Merc Hi Perf. Any ideas of propheight?
Cheeers, Toffen - Norway
06-10-2003, 08:21 PM
#2
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If that is the boat you are mounting them on, I would first check to see if the hull is structurally sound(stingers, hull deck joint, all glass work basically).
And if you think it can handle it make sure the transom has a lot of reinforcement to your stringers. I have seen transoms break before and it is not pretty.
This seems like an unusual set up so you might be the one doing the trial and error runs.
Now I am not opposed to too much horsepower but that seems a bit much for that boat. Do you have a "Coast Guard" or the like over there that will fine you money if your boat has to much horse power. Why not find a good used 25-28 foot cat that is set up for outboards but does not have any rigged.
Also try this message board, www.screamandfly.com
And if you think it can handle it make sure the transom has a lot of reinforcement to your stringers. I have seen transoms break before and it is not pretty.
This seems like an unusual set up so you might be the one doing the trial and error runs.
Now I am not opposed to too much horsepower but that seems a bit much for that boat. Do you have a "Coast Guard" or the like over there that will fine you money if your boat has to much horse power. Why not find a good used 25-28 foot cat that is set up for outboards but does not have any rigged.
Also try this message board, www.screamandfly.com
06-14-2003, 03:06 PM
#3
Gold Member
Gold MemberThread Starter
Twin PMS's
Hi!
The Phantom 23 and 25 (as mine) runs twins (both 2, 2.5 and 3 liters engines) in the offshore cirquit in Europe. Then a second fueltank is added in front, making the balance of the boat better. I also have a ballasttank in front making it possible to rebalance the boat in high seas.
The transom is 4 inches and two large stringers.
Current weight is:
engine = 112 kilos
powerlift = 35 kilos
added setback 7,5 inches = 135 kilos
in total weight on the transom = 382 kilos
Two PM 300's direct on transom is 424 kilos.
The Phantom 23 and 25 (as mine) runs twins (both 2, 2.5 and 3 liters engines) in the offshore cirquit in Europe. Then a second fueltank is added in front, making the balance of the boat better. I also have a ballasttank in front making it possible to rebalance the boat in high seas.
The transom is 4 inches and two large stringers.
Current weight is:
engine = 112 kilos
powerlift = 35 kilos
added setback 7,5 inches = 135 kilos
in total weight on the transom = 382 kilos
Two PM 300's direct on transom is 424 kilos.
