How important is a higher cruising speed?

[markpierce]

One advantage to a bit more power than you need is that the motor isn't running all out when you hit your top speed. So lets say I need 300 hp to hit 14 knots and then I can't go faster, if instead I have a 350 hp motor running at 300 hp to 14 knots, in theory the motor should last longer. And at cruising speed, the revs on the larger motor are less than the revs on the smaller motor. ...

With my single NA 80-HP Deere, the engine is only working at 47% at one knot below hull speed (my normal cruising speed), and 72% at maximum boat speed. Besides, diesels like to be "worked."

 

[dirtdoc1]

I wish I had about 3 more knots. I max out at about 12 which can get me out of a lot but I haven't tried a bar yet. Following seas where never a problem in my Carver C34. It went 30 mph. Now I'm limited to about 13 mph and following seas are much less comfortable.

 

[mcarthur]

For the most part, I could argue that a speed option is not as much as a crucial safety items instead of just personal preference. We have a number of members here with slow boats that have safely navigated all over the US and in many parts of the world. Perhaps hull design or size is a more important feature.

As for weather, you generally cannot outrun weather, even with a fast 20kt boat. Sure, you can better position yourself at times. Weather is often fast moving, widespread or both. I could argue to deal with the weather that trying to out run it.... or just stay in port.

So is there a speed that is a minimum run-away-from-bad-weather speed? Of course you can go faster to run, say 200kn , but I'm thinking a minimum. From the posts here, it looks that around 10-14kn could be said to be a common minimum?

Of course if you're 1 day away from a fast-moving hurricane in the open ocean coming right at you then 5kn isn't going to be fun. 10kn means 240nm in a day which is pretty good to get you out of the worst I would think. 14kn would be 340nm in a day which, while "better" may not be terribly much more. So how would 10kn be as a minimum safety speed?

The other factor is how fast can your boat comfortably go for days and days in rougher water? Can most boats that could hit 20kn maintain this for days in a rougher ocean, or is 10kn a more likely scenario for both human comfort as well as not making the boat and systems suffer?

Oh, and reiterating the OP's title that I meant cruise speed, not short-term get-over-the-bar speed: something that can be kept up for days and days. Implicitly I'm thinking more open water than a (long!) river.

 

[dirtdoc1]

For slow boats with a flat transom following seas can be an issue. When I had my fast boats, following seas were great. I'd push the throttle up and ride the waves. No pounding just a smooth ride. I cruised the San Francisco Bay and Delta for 40 years in fast boats. I could run from Redwood City up to Sacramento in a day. I'd usually break it up in to two days. In a fast boat there isn't much to worry about. Big slow boats are a completely different thing. With my trawler, following seas can be a real pain. Broaching is always a concern. I'm learning how to cruise the Pacific Northwest. There are a lot of narrows that can be treacherous during tide change and the ability to run over 12 knots would be advantageous. But I can't so in many areas I have to watch my timing and at times wait until the tide slows.

I'm new to ocean and coastal cruising and I'm also new to trawlers. There is a lot to learn and the type of hull that you have makes a difference. Speed can get you out trouble. If you have a slow boat you have to learn to watch the tide and learn the area that you're in. Learn where all the narrows are and pay attention to timing.

In open ocean speed may be less of an issue. I guess I'll find out when I run down the coast to Redwood City next year. This year is all about exploring more of the PNW.

 

[AusCan]

Those that like to get up and plane to smooth out rough seas are surely talking about fairly minor rough seas. There would be a limit where the swell and waves are big enough to pound most planing boats to pieces.

At that point, I rather be in a full displacement boat.

Or in one of these.

https://rnli.org/magazine/magazine-featured-list/2018/november/meet-the-shannon-lifeboat

 

[dirtdoc1]

Those that like to get up and plane to smooth out rough seas are surely talking about fairly minor rough seas. There would be a limit where the swell and waves are big enough to pound most planing boats to pieces.

At that point, I rather be in a full displacement boat.

Or in one of these.

https://rnli.org/magazine/magazine-featured-list/2018/november/meet-the-shannon-lifeboat

You have to learn when to go fast and when to slow down. As with any boat there are always compromises with the design. You also need to learn what type of boat is appropriate for the type of boating that you do. I learned the hard way $$$. No boat meets all requirements.

 

[Arun52]

Those that like to get up and plane to smooth out rough seas are surely talking about fairly minor rough seas. There would be a limit where the swell and waves are big enough to pound most planing boats to pieces.

At that point, I rather be in a full displacement boat.

Or in one of these.

https://rnli.org/magazine/magazine-featured-list/2018/november/meet-the-shannon-lifeboat

I agree with you. The RNLI has spent a lot of time and money in perfecting their designs.
I have great faith in my boat in any sea condition.

 

[North Baltic sea]

Wifey B: It happens here too. Seems Jupiter Inlet has far more than their share. It's had a lot of deaths over the years. You see so many small boats there and operators without knowledge or experience and then there are the overloaded fishing boats too bringing their excess catch in.

Here's the perfect example of what we've been talking about.

https://www.facebook.com/watch/?v=1938073453076542

Educational video, folowing the sea from dangers to boats all boat/ship.

Here's an interesting theory when the wave starts to be at risk of crashing the boat.

Dangerous waves and your boat - Ocean Navigator - Ocean Voyager 2011

NBs

 

[North Baltic sea]

I agree with you. The RNLI has spent a lot of time and money in perfecting their designs.
I have great faith in my boat in any sea condition.

Hi, even if your boat is very seaworthy, then a skilled skipper will make your trip safe in a really hard way at sea, not just a boat and every one of us sometimes makes mistakes, so I hope you respect the sea, not just technology.

NBs

 

[O C Diver]

Educational video, folowing the sea from dangers to boats all boat/ship.

Here's an interesting theory when the wave starts to be at risk of crashing the boat.

Dangerous waves and your boat - Ocean Navigator - Ocean Voyager 2011

NBs

Interesting article. If I stay out of 15' seas with my boat, it shouldn't rollover. I'll try to remember.

Ted