The stove oven combination uses two exhaust pipes, one for each portion. The pipe is 28mmID flexible stainless steel with a fiberglass sock over it. The exhausts can vent out the hull side or out the deck and can be up to 13' long, each as long as there are not too many tight radius bends in the runs.
If venting through the roof, then a covered or closeable through hull design must be used. The oven makes and stores more heat than the stove, so a more heat protective through hull/deck fitting must be used.
If the 87D is to be gimbal mounted, then a short coil of exhaust pipe needs to be built into each exhaust run to allow unit excursion.