Southern Cross 31, assisting a friend

[Tatheelrod22]

I am in search of advice here on the house of a friend. He is going to be new to sailing but is looking at a Southern Cross 31. He is very interested in this boat and would love for me to come to Florida to accompany him on his second look before he has a survey.
I am familiar with the boats and have admired them for years. Actually about 20 years ago I looked at one and was very interested until my wife reminded me that given the type sailing we were doing at that point in our lives she was not crazy about the size of the cockpit. I’m not complaining given I am now on my 13th sailboat.😁
My question is this. I may find the time in the next couple of days to do more research however the thing that concerns me the most is the vessel was at some point re-powered with a 10 hp Yanmar. My gut feeling is that has her woefully under powered. I would think nothing less than a 20 to 25 HP for a vessel like this.
I welcome your thoughts, except for those who want to say “you don’t actually have to have an engine. “ I get that but it isn’t practical given his skill set or likely use of the boat.

[Benz]

My Cape George 31, which weighs 20,000 pounds, is powered only by an 8-hp high-thrust outboard. A ten-horse Yanmar oughtta be fine.

[Celestialsailor]

My general rule is 400lbs. per hp. A SC 31 is 13,600lbs. So around 34hp. =/- 5hp.

[Adelie]

The current general rule of thumb for most builders seems to be 4hp/long ton (2240lb).

The old rule of thumb for designers was to maybe reach hull speed in flat water and 2kt upwind in 20kt with 2nm of fetch.
10hp seems about right for the old rule of thumb.

The original design had a 22hp diesel.

Given how under canvassed the boat is, it probably should have a bigger engine as it won’t perform well in light air and will likely motor or motor-sail whenever it goes light.

[NorthCoastJoe]

I put a Yanmar 3GM30F ( 27 HP ) with a matching prop in my Pearson 30. I love having the power when I need it, we can get 4 knots current at the Golden Gate.

[Orion Jim]

Originally Posted by Adelie

The current general rule of thumb for most builders seems to be 4hp/long ton (2240lb).

The old rule of thumb for designers was to maybe reach hull speed in flat water and 2kt upwind in 20kt with 2nm of fetch.
10hp seems about right for the old rule of thumb.

The original design had a 22hp diesel.

Given how under canvassed the boat is, it probably should have a bigger engine as it won’t perform well in light air and will likely motor or motor-sail whenever it goes light.

22 HP seems about right. Less would be practical for a more conservative owner and more would be in line with what is considered “normal” by current standards. That’s the great thing about boat ownership, we all get to decide what fulfills our wants and needs.

[Hoodsail]

The SC owners site notes the displacement of a 31 is 13,600 pounds. And looked up Nigel Calder's recommendation for displacement hull and he's at 1hp/500 pounds displacement. But he qualifies that hp number as being a maximum needed and notes you need to figure into this the type of propeller are you driving, 2-3 blade, fixed, variable pitch, etc and gearing of transmission. My Bristol is 15,000 pounds empty and driven easily with 14", 3 blade, fixed prop, trany is 2:1 and 25 hp westerbeke. Even motoring to windward in 20-25 knot winds, 3-4 ft seas, able to make 5+ knots. So I am well under Calder's maximum, but considerably over your 10 hp..

[Otium]

I have an SC 31 with the Yanmar 3GM30F. So far seems a good size. As noted above; labels say 27hp. (some docs will argue you only ever really see about 24). Either way 10hp seems light.

At 13,600 lbs SC's are heavy for 31' and most would acknowledge that it takes a bit to move her. You can of course sail her w/o an engine, see:

https://www.youtube.com/watch?v=1w2H4smScuM

, or with a 10 hp outboard, if you have the experience and sailing skills to do so. Even then, can you do so safely?

However, I would not recommend either of these approaches if your friend is just learning to sail. I think to attempt either of these without a significant amount of sailing experience and skill is a little risky; but to each his own. I try not to tell others what to do, because I don't like anyone trying to tell me what to do. I'm a firm believer in the individuals freedom to choose and in the fact that our choices have consequences.

But, you may wish to remind your friend that he will be responsible for any damage he may cause to others property (docks, boats, etc), and for personal injuries, while captain of his vessel. Trying to maneuver his craft in tight or congested waters w/o good sailing skills or w/o adequate power in an auxiliary for his skills, could have serious consequences. Just something to think about.

If I were to make a recommendation to a friend, who was just learning to sail, I would advise;

1. Start with a smaller boat to learn on; They cost less initially, maintenance is less, size of everything is less...and you will learn while gaining confidence.

Then you can always move up to a larger size when you feel you're ready. I started (as many others have), on a smaller 18' sloop in a local sailing club, (simple rig, inexpensive, and a lot of sailing clubs have these size boats and smaller. This is a really good low risk option to get your feet wet!). Then my first boat was a 21' sloop, (an old Victory w/o engine), that was an awesome learning experience, especially good for learning how to pick up moorings under sail, anchoring basics under sail, and arriving at and leaving the dock under sail (and oar), lol. My next boat was a 27' Pearson Renegade w/small 9.9hp outboard. It was a gradual progression over the last 20 years to the SC 31'. (Note: I have recently started ogling some SC 39's. The Admiral is not amused...)

2. If he has to have the SC 31'. I would encourage him to see about fitting her out with a little stronger auxiliary. As others have said, and I agree, something in the 22-27hp range would provide a safe reliable iron sail. I wouldn't be afraid to search the used/rebuilt market as well as searching for new. Look through other forums here you will find a lot of recommendations for both new and used diesels.

Best of luck to your friend. It's a lifelong addiction...but one well worth having.

[Adelie]

Originally Posted by Otium

...

You can of course sail her w/o an engine, ...... , or with a 10 hp outboard, if you have the experience and sailing skills to do so. Even then, can you do so safely?

.....

Yes, boats can be sailed safely without an engine. Plenty of examples of that.
One person on this forum sailed around the world without an engine.

So it is reasonable to assume that a boat with a 10hp engine will be just as safe.

Learning to sail on a heavy engineless keelboat is probably not a good move.
Learning on a heavy keelboat with a 10hp engine, it's arguable. Depends on where the sailor will be learning and what the wind, current and shoreline conditions are like where they are. And what sort of instruction is available. Sailing with an "underpowered" engine is more likely to make one think twice about doing something ill advised in the first place which is a good habit to have. I've seen plenty of follks come to grief thinking that a large enough engine would get them out of predicaments.

If the OP's friend thinks that they will want a "normal" sized engine in the long run, they shouldn't buy this boat in the first place.

[Mithril Bham]

I won't speak to power since it was covered above. I will say that I spent significant time on a SC 39 and loved it. Be sure to make sure the core under the deck has no rot.