Marinebeam used to sell the 13W 24V lamp. I purchased the 4 1/2" PAR36 LED Sealed Beam Replacement Bulb (SB-PAR) with a 30º, best option if you want all the light on the deck only.
You could choose voltage as well. But now it appears to be unavailable.
However the 10W LED Tractor Light Replacement - 4.5" Sealed Beam PAR36 could be a good option, with an agle of 38º and 10W, seems it could work as well.
Older Maramu 1982, #94