Volvo V Cats

Since no one has replied yet. I will try to get you started. 3126 and 3116s had problems early on and not highly regarded by the boating public. Something about French blocks being cast wrong.(??) Years ago slip mate had I believe a 3126 (could have been the 3116) that needed to be replaced and even back then he was told that they were no longer available. So I would do further digging to see about parts availability for the 31 series cat. In the states Volvos have a reputation for very expensive parts that VP dealers sometimes have trouble obtaining. In Europe that maybe different. I know nothing about Volvo TAMDs. Keep in mind I am not a mechanic nor work in the boating industry. Just a boating enthusiast that keeps up with things related to boating.

Ouch,,
I know the Volvo is the better engine.
I know the Cats have a larger service network.
The Volvo is as solid as it was when released.
The Cat, now in it 3rd generation (now C7) has had some growing pains.
I would give the Volvo a lil more performance edge.
Volvo parts come from over the Atlantic and may cost more when available.
Cat parts cost about what other old engine parts cost and usually always available.
Both need a real tech for anything past changing the oil/filters or any other hang on service.

I have never owned either model.
I have managed boats with them.
I have preformed services and light repairs on both of them.

Just looked up and noted Gibraltar,,
Part and service shops may be different for you.
Part and service shops may be the largest issue to help you shop between these two models.
If I was in Gibraltar and had a Volvo shop like mine here in N E Florida, I would go Volvo.
The big Cat shops in NE Florida sux. There is one independent Cat shop in this area, He would be the only reason for me to go Cats.

Ralph, the Cat 31 series is still in production and called the C7? I did not know that. I thought it was discontinued.

I started to question myself. Nothing on the Cat website.
Then Da Duck found this;
https://en.wikipedia.org/wiki/Caterpillar_3126

The Caterpillar 3126 is a turbocharged 7.2L inline 6-cylinder diesel engine manufactured by Caterpillar and first introduced in 1995; it was the first electronic mid-range diesel engine that Caterpillar produced.[1] It is the successor to the Caterpillar 3116 engine and was updated to become the Caterpillar C7 engine in 2003.[1] It is a medium-duty engine and has been used in dump trucks, long haul trucks, ambulances, buses, RVs, boats, cranes, fire trucks, and more.[2] In 1998, Caterpillar released an improved version, the 3126B; in 2002, the 3126E was released; though these improved versions only affected engine electronics, not the actual engine design.[1] Caterpillar launched a three-tier system of overhaul kits for the 3126 and its C7 successor in 2011.[3]