30+ Freeboard? Stern seems low in the water when moving fast. Help troubleshooting appreciated!

[ScopWitz]

Hi Everyone! This is my first post, and I have to say thanks for supporting such a trove of information about Ericsons!

My wife and I have owned a 1985 Ericson 30+ for a few years. Our main question is, "What is the freeboard suppossed to be on a 30+?" I have looked high and low foir this information but can't seem to find it.

We live in Chicago and recently took a trip to South Haven, MI. While motoring back at 5.5 kt, in the middle of the night, we noticed that the stern was very low to the point where the exhaust port was almost in the water. The bilges we complely dry, and when we slowed down the stern came up and the bilge pumps pushed some water out of the back.

Rather than risk a lake crossing, we headed to Benton Harbor / St. Joe for the night. We eventually got a tow back to Chicago. During the tow we were going about 7 kts and the stern was EVEN lower, submerging the exhaust and partially up the ladder. On the dock back home, a neighboring slip suggested that it might be a partially filled or low water ballast. Since my understanding of the 30+ is that it uses the water tank as ballast, I went and checked and the tank was indeed almost empty. Is this what the problem is?

How do I know that I have got the freeboard back to what it should be when sitting in the slip? When sailing or motoring, where should the water line be off the stern? I don't recall ever seeing it be that high before. I haven't gone underneath to see if we are dragging anything.

Thanks for all your help!

 

[Loren Beach]

Your Ericson does not use "water ballast", but will always perform a little better with less water weight carried aboard. (Or less people or cases of beer, or cans of beef stew...)

As for the exhaust thru hull, it may well be under the water when your hull speed goes over about 6 or 6.5 kts. That's normal for any displacement hull.
Question begged: why did you need a tow back home? There must be a story there somewhere.

 

[Christian Williams]

Well, on the E38, the stern certainly squats under power. My general rule is throttle up until the transom hits the water, during which the exhaust under the counter is well submerged. Normal, although I back off a little because with the transom submerged we're just making a bigger wave and additional forward progress, not much.

Boats make a bow wave, which dips mid-boat, then rises at the transom and the wavelength limits hull speed for a displacement boat. Longer boat, longer wave, therefore faster, all else the same.

Towed at 7 knots you were above rated hull speed for a 30-footer, meaning the tow was literally dragging you through the water.

When sailing everything is different, as the propulsion isn't from a screw or a tow, but from the center of effort of the sail plan. The stern doesn't dip as much, although with a following sea it may seem to.

(When being towed it is often necessary to tell the towboat to slow down. Or used to be, when motorboats offered tows to sailboats, and then set off at 15 knots! But, uh, those Corinthian days are long gone. And today's pro towboats know the limits)

 

[bigd14]

On my 30+ the exhaust is often under water when motoring especially with more than two people in the cockpit. Doesn’t seem to cause any problems, and I’ve stopped worrying about it. The bilge pump going off seems a bigger concern to me. Check all thru hulls, hoses, rudder gland and shaft seal. I had leak problems with all of these when I got my boat. Several hoses and the old PSS shaft seal were very close to failing and would have likely ended up sinking the boat.

At the dock the boat sits a bit bow down because the PO had 60 feet of chain in the anchor locker and I have kept that setup. Here is a photo.

 

[Frank Langer]

On our 1984 E30+ the exhaust outlet is in the water when cruising at about 5.8 knots. At dock it sits a couple of inches above the water. No cause for concern.
Frank

 

[ScopWitz]

Thanks everyone for the helpful responses!

 

[ScopWitz]

Your Ericson does not use "water ballast", but will always perform a little better with less water weight carried aboard. (Or less people or cases of beer, or cans of beef stew...)

As for the exhaust thru hull, it may well be under the water when your hull speed goes over about 6 or 6.5 kts. That's normal for any displacement hull.
Question begged: why did you need a tow back home? There must be a story there somewhere.

It was quite an adventure for he—a fair amount of engine trouble coupled with a number of days of high waves, and the end of our vacation days.

 

[william.haas]

It was quite an adventure for he—a fair amount of engine trouble coupled with a number of days of high waves, and the end of our vacation days.

Adding in the 28’s stern will also drop under power and a higher speed. What harbor are you in?

 

[Seth]

Hi Everyone! This is my first post, and I have to say thanks for supporting such a trove of information about Ericsons!

My wife and I have owned a 1985 Ericson 30+ for a few years. Our main question is, "What is the freeboard suppossed to be on a 30+?" I have looked high and low foir this information but can't seem to find it.

We live in Chicago and recently took a trip to South Haven, MI. While motoring back at 5.5 kt, in the middle of the night, we noticed that the stern was very low to the point where the exhaust port was almost in the water. The bilges we complely dry, and when we slowed down the stern came up and the bilge pumps pushed some water out of the back.

Rather than risk a lake crossing, we headed to Benton Harbor / St. Joe for the night. We eventually got a tow back to Chicago. During the tow we were going about 7 kts and the stern was EVEN lower, submerging the exhaust and partially up the ladder. On the dock back home, a neighboring slip suggested that it might be a partially filled or low water ballast. Since my understanding of the 30+ is that it uses the water tank as ballast, I went and checked and the tank was indeed almost empty. Is this what the problem is?

How do I know that I have got the freeboard back to what it should be when sitting in the slip? When sailing or motoring, where should the water line be off the stern? I don't recall ever seeing it be that high before. I haven't gone underneath to see if we are dragging anything.

Thanks for all your help!

This is 100% normal. All displacement boats settle in the water as they go faster. Physics at work. What you are seeing is not an issue and as noted by others, the exhaust is ok if under water at times. There is a check valve to prevent water going into the engine, but in any case with the engine running there is positive pressure so water would not enter anyway. And while this is all fine, you might experiment with less weight aft to see if you can gain a little speed. Dragging the stern is not best for speed but is inevitable. Too much weight forward isn’t fast either so finding a balance will optimize speed (a very small amount). But do not worry about this and enjoy your great boat!

 

[Loren Beach]

This is 100% normal. All displacement boats settle in the water as they go faster. Physics at work.

So true. We've just returned from a 33 mile trip for a long-weekend club cruise to a state park dock at Beacon Rock on the Columbia River, for two nights. With a recent bottom scrub, we could do 7.1 kt thru water at 2600 rpm. What with current, our SOG was down to 5.8 for long distances against it and over 9 returning. Little wind except some that was against us, so it was all motoring.
The Olson has a much flatter hull run aft than the BK hulls, so we have more speed than our DWL would indicate. At speed, the following wave is just below our exhaust outlet on the stern and nearly at the cockpit drain outlets (they are lower than the sole intakes I should note).
Pushing another 200 rpm barely nudges the speed much higher, with our 25 hp engine, and burns too much fuel. This speed produces a noticeable stern wave just behind the hull.
"Physics rules..."