Use of existing cable for NMEA2000?

[Boots]

I am updating the existing DataMarine electronics package with a new B&G NMEA2000 system.
Depth& speed transducer, mast head unit, gauges and chart-plotter.
But the cabling through the mast is proving difficult to replace, so I was considering splitting the new mast head cable,
and slicing in 4 cores of the existing DataMarine cable.
Im not sure if NMEA2000 requires twisted pair, or some other specific type of cable.
The length of the mast is about 46 feet.
Your thoughts?

[PeterSailor]

In N2K cable, red and black is 12V power, and anything over #22 will do the thing. Blue and white is data and physical arrangement give them a characteristic impedance of 120 ohms (not DC resistance which is 18 ohms per 1000 ft, but the equivalent impedance at the signal frequency). And they are twisted pairs, individually shielded for noise immunity. You might be lucky and find a shielded-twisted pair or triad in your Datamarine cable. In the worse case, it will not work. I think it worth the try.

[Outlaw7]

The biggest thing is unless his new mast head unit has a built in terminator then he will have to add a terminator at the mast head as the mast wire itself exceeds the length of a drop.

[Boots]

The B&G mast head units do include a NMEA2000 terminator, so I'm ok there.
I believe the DataMarine cable is twisted pair, and it is shielded.
As they say, "Plan for the worst, and hope for the best". I'm giving it a go.
Thank you for your replies.
DBooton