Storm Safety & Handling - Displacement vs Semi Displacement

What is your experience is the far more important question. The boats can generally handle more than the operator. There are many boats, some full displacement, some semi, that can handle those conditions in an emergency. There are none in that size range that are actually going to be comfortable in those conditions.

You have a dream you're in the very early days of pursuing. You're doing the right thing by asking questions. At first any of your Caribbean cruising would likely be island hopping rather than crossing. However, you will need to learn and experience, even to be ready for that. It also tells me that if you intend to use it that way, it might be wise to start with the most forgiving boat you can find. There are many that are proven in rough conditions. You'll try to avoid those conditions. But if you do encounter them, then it's going to be far more about you and any other crew, than the boat.

I would not recommend operating ANY 50 ft boat intentionally in 8-9 ft seas with 30-35 kts winds.

Ditto ++ I am fortunate to have one of the best 50 SF made and 60,000 lbs - ain't gonna do it! Swells are one thing, but with that wind the tops of any waves are going to be knocked off for some pretty nasty conditions. RT and I will wait for you at the dock with clean trousers.

Also, unlike sail boats, very few pleasure power boats will right themselves once they go past that magic degree of yaw particular to the hull - I'm sure there is a professional term for that.

Mars

A 45' center cockpit Morgan is a hearty vessel, indeed. Power boats of comparable size will not even be on the same comparison chart regarding seaworthiness. A storm reefed sailboat has inherent stability that a powerboat only gains by increasing in size and displacement. Your Morgan's stern design takes into account following seas, Flat power boat transoms do not, regardless of underwater design. It's going to be "squirrelly" ride with all designs, just a matter of how much. Once you start losing water velocity across the rudders it just gets worst - and yes you can lose control. A sailboat's rudder surface is far greater that a powerboat's. The one good thing about power boats is the power, though. Ride the back of a following sea if you can, like you're coming in an inlet, or if you have a large foreprint, power thru. On the nose, its all about spray. Is it white water or green water coming over the bow? Does the hull throw the water out or up? When you come down the back of the wave does the nose dig or stay up? Let's not even talk about a broach in those sea conditions - you will certainly be wishing you had a ballasted keel and a sail. Another consideration is helm location, inside or out - visibility considerations. Up or down - pitch and yaw are magnified on a bridge.

As you develop your plan, you might want to look into renting various boats in the Carib from places like "Moorings" or other bareboat charters to test a number of different hulls. Don't know which Fla. coast you are located along, but if you have access to the gulf stream, test some hulls going across that in a 40 knot Nor'easter.

Good luck. Keep us updated on your progress?

The 46-53 Hatteras convertibles will handle more weather than you want to be in. 9-10' seas are, in no way comfortable, but I never felt that my life was in danger. Most of the Down East hulls are semi-displacement and I've never had one try to swap ends in a following sea. Both hull designs have substantial keels. I've never been on a Nordhaven or a Selene so I don't know if it's all marketing or if they're the real deal.

I agree with all of these posts.

I just want to add this:

I would not intentionally operate a 50 ft boat in those condition or venture out with a forecast in those conditions.

In those conditions, it is extremely difficult to mitigate any increased risk or deal with any unforeseen condition or emergency.

A routine maintenance evolution, like a clogged fuel filter could compound into disaster.

Can you successfully operate a 50ft power vessel in 8-9 ft seas w/ 30-35 kt winds? Yes, but that is extreme.
Have I done it? yes
would I intentionally do it again? no
do I recommend it? no
will the boat handle more that you? yes


My personal threshold for operating a 50ft SF is probably 4-6 ft and 15-20 kts maximum. and that is extreme.
I wont go out unless the forecast is under 15 kts and 3-5 ft.
Its just not enjoyable if I really don't have to be somewhere.

In regards to the recent sinking and loss of life of the commercial vessel south of PR during a Summer Fall Hurricane:
My wife recently asked me, "how come those professional mariners weren't able to get into life boats?"
I asked her, do u remember that time we went to X Island and it was really nasty out, I bent a wheel on a bar on the way out, and the boat was loaded , and slow, and I had to change a filter, and the boat was getting slammed in the 6-8 ft and you were sucking diesel fumes and sick? do you think you could shimmy up on the bow as the boat was pitching and rolling, don your survival suit, ensure the EPIRB is deployed and get into the survival raft if it deploys as the boat is going down?
she said "now I get it"

Can you do it? yes

but when things go really bad, its usually a number of things or a number of failures.....

I wont intentionally operate in conditions that could compound mitigating un-anticipated risk or un-anticipated issues.

I didn't think, I certainly hoped not, that the OP was talking about going into those conditions intentionally. I guess I just assumed he was referring to getting somehow caught in them as they suddenly came up. However, that was before reading his Lake Michigan bravado. The fact that he's done it many times on Lake Michigan tells me that any assumptions I was making regarding his judgement I now find myself needing to reevaluate. Power boats are not for sailors who are proud to be able to say what conditions they can brave and handle. This is the "I am sailor. Here me roar. I can handle anything" attitude. The one that leads to sailors lost at sea and rescuers putting their lives in jeopardy to rescue sailors. This isn't an attack on all sailors as most are intelligent who make good educated decisions, but it is against that faction of sailors who don't show that wisdom. These are the ones who sail off Hatteras when storm warnings have been out for days or from Texas far out in the gulf when no other boats are going out.

Power boats aren't designed to prove how brave and macho one is. They're designed for pleasure and to be used wisely. The wise recreational power boater doesn't go by a calendar and knows when to stay in. Now they will face the risk of conditions getting bad unexpectedly but when coastal cruising they always have a safe port in mind for escape. When crossing oceans they go either better prepared and pick the best possible window, boat, crew, have extensive training and preparation and still hope beyond hope that conditions will remain rather benign. And, I personally, am not going to attempt to cross the Atlantic in any 50' powerboat.

Me either, I call it at a 5' forecast with most all 50' boats. Handle it and more yes, worth breaking stuff and having stuff fall off the walls, no. Unless the forecast is a swell, then it just depends on period. But direction also has to do with it to.

It happens in inlets if the inlet is shallow and it's rough...... if you're coming in and at the bottom of an 8' wave, then you are 4' below what the depth would normally be if it's calm, 4' above at the top of the wave. So if there is usually only 8' of draft in the inlet, you draw 5' and you end up riding in the trough of a 8' wave.....boom......

+1 on this.
Wave height and swell with longer interval is fine, within reason. If fishermen on the East Coast of Australia stayed home every time the wave height was greater than 5', then we would not get too much fishing time.
A forecast of 1.5mtrs to 2mtrs (5' to 7') Swell with wave height of same, 5' to 7', is a good day. And no, I am not being macho or anything other. Check the intervals and direction of swell/wave/wind if there is any concern about the weather.
Conversely, just because the wind has dropped and weather is good, still check. After a a few days of heavy wind (not necessary storms), it can take days to settle.

Agree, I fish out of the Shinecock inlet on LI NY. But the OP was describing 8-9's with a 30-35 knot winds. I'm not sure I could get out of my inlet even with a 90 footer. If I were caught in it, I could get home or to a safe port, but I ain't going out into it...I'll go to the local fish store. In those same conditions described by the OP, I have diverted to the north side of Montauk to get into the lee, rented a slip and waited to go home - but not before my crew and I had rare steaks and some cold beers.