Thanks.Well, I know that you cannot get a CE rating on a sailing catamaran less than 40' long. Don't know if that holds for power cats. So there is one (or maybe less) point in favor of monohulls.
A second point is that we (or at least some of us) understand the characteristics of mono hull blue water trawlers: ballasted so the point of vanishing stability is 90 degrees or more, downfload prevention, heavy scantlings particularly windows that can stand up to a wall of blue water over the bow, simple robust sytems with redundancy for critical items.
I don't have the same understanding with catamaran power trawlers. Beebe never wrote about them. My gut is that they have never made serious blue water passages, but I am sure the group will correct me.
What is a serious blue water passage. In my mind it is anything longer than reasonable weather forecasts can cover, 5+ days.
David
That's fair weather. We've all seen more on the Chesapeake, Long Island Sound or Great Lakes....We've avoided seas more than about 3-4 feet or so.
There you go!!I have about 800 nms on a friends 2014 Horizon Power Cat 52, over half of which in the Gulf off Florida's West Coast between Cedar Key and Dry Tortugas. We've avoided seas more than about 3-4 feet or so. The ride is fine, a bit jerky for my tastes. My friend tells me he avoids beam-seas like the plague, but it could be that it's a super nice boat and not everything is nailed down. Boat carried 700g of diesel, and burns about 35gph at 18-kts; or under 7 gph at 9-kts. Small rudders mean she'd really rather be going fast, and she handles chop pretty well at 18-kts, though a seriously wet ride (as you'd expect). I really like sedan layouts where the main living space flows into the aft deck - a powercat is superb for that. An extremely nice layout for warm weather cruising.
Malcolm Tennant (sp?), either NZ or OZ, apparently designed the penultimate bluewater power cats. If you're interested, you may want to take a look. One of his designs - Domino - is for sale (YW link below). Frankly, I think cats make more sense at 60-feet and over. Don't know why I say that, but the lines seem to blend nicely, and I suppose the bridge deck gets higher.
https://www.yachtworld.com/boats/2009/malcolm-tennant-domino-20-3495698/
Domino has been for sale for a long time. I'm guessing the single head has a lot to do with it. 60-foot cat with one head? Adding a head might be the only time a remodel of a boat might make a profit.That Domino boat has 2000nm range at 20 knots....4000 at 10....obviously likely much farther going even slower. There is no "hump" as it relates to going those speeds. IOW, the performance curve is linear through the speed ranges...so you could likely expect 3000 miles at 15 knots. My only knock on the boat is it has only one head...
Notice the shape of the underside of the (relatively narrow) bridge deck. Designed to break up the water under it and avoid the slamming cats are known for under the right (wrong) conditions.
Besides all the positive and negative things already posted, most, if not all, the production cats have built in seating. That is a deal breaker for me with back problems. I want recliners to relax in and that isn’t an option in most cats. So that would eliminate them from consideration for me.
The 2 major questions you need to answer for hull choice is speed and fuel cost.
We had a Knight and Carver, Mono 67ft flybridge cruiser naiad fin stabilized and now own a malcom tennant 60ft cat both had around 450hp a side power.
The mono with older engines traveled at 10kts for about 18us gallons a side and 7kts @ 12 a side. The cat travels at 18kts@ 18us a side and 9kts @ 4us a side. The cats top speed is 25 the mono was 14. The mono was fin stabilized with naiad and was far more comfortable in large seas at 8-10 kts than the cat is at any speed.
For coastal and Caribbean cruising well built ocean designed power cats are great but for ocean crossing a mono is more comfortable on big swells with waves on top and to us in the middle of the night cruising in nasty conditions the mono just felt a lot better. We are currently building a new 65ft cat because of fuel and speed and expect to cruise @19kts using 17 us gallons a side and 27kts at 45 gallons a side ( sea trial top speed). We will only carry 2500 gallons so I do not plan on seeing 20+ after the sea trial and our normal fuel load will be 1500 gallons.