Willard 30 cruising speed

Can anyone tell me what the normal cruising speed and rpm are for a Willard 30 Nomad with the Perkins engine.

I was looking at a Nomad for possible purchase and during the sea trial we averaged about 4.5 knots. The owner felt that the propellor needed cleaning, and said that normal cruising speed for his boat was 5 knots at 2100 rpm. This seems slow for me, and a search online suggests that 6 knots is normal, at around 2200 rpm. But most of these cruising speed references are from boats for sale listings, and I was wondering if anyone has some real-life cruising speed experiences to share. My Albin 25 does 6.5 knots, so the Willard should easily cruise at 6 or more, IMO.

Also, any idea why the speed would be below normal (besides the condition of the hull and propellor). Thanks.

Do not know an exact # but I think we are talking pure displacement speed on this boat. My guess is that WL = about 25 feet so about 1.3xsq root of 25. would give approx. max speed 6.5K. If an accurate measurement of boot speed is not six or above something is wrong. It should not take a lot of HP to reach disp. speed. Things to look for dirty bottom or fouled prop-wrong prop-poor transmission of power from motor to prop- extreme overweight of boat floating far below designed water line-dragging your anchor.

When was the boat last pulled. I would suspect a gnarly prop/shaft/running gear. Was the boat speed from a GPS or knotmeter?

We've been at it for 10 years w our W30 as in my avatar at a rate of 6.15 knots 95% of the time running 2300rpm. 2500 gets us 6.4 knots. We have a Mitsu that has the same bore and stroke as the old Perky and it may make one hp more but I'm not sure. Close enough to the same to be called that. The above is with the WOT rpm of 3000 ... rated rpm for both the Perky and the Mitsu.

While testing for boat speed run where there is the least current. Run a couple of minutes at a given rpm untill it's very stable .. observe that speed on the GPS and turn to a course opposite what your first run was (a 180 degree turn) and make observations on that course. Splitting the difference of the speed indicated will be very close to the true "over the ground" speed.

I don't have a Perkins, I have a Yanmar 4JH2E, and I run 1850 rpm's at 5.5 knots and 2650 gets me 7 knots. Have a 3 bladed 18LH12" prop and the engine is naturally aspirated, 2.63:1 ratio reduction gears.
Fuel burn at 1850 is .42 gph and at 2650 is 1 gph, the hull has the "happy bubble" feel at 5.5 knots and at 7 it's digging a hole and has pulled the exhaust under water. I am sure it would be happier somewhere in the middle but the engine harmonics don't care for the range in the middle.
I wish it had a 3JH instead of the 4JH, 70% of throttle is 2650 and I don't like to cruise there. I usually cruise at 1450 or 1850 (4.5 or 5.5 knots) and travel at 2650, there is no point in running more throttle than that since I'm just burning fuel and not going any faster. Sea trial achieved 7.8 knots at 3600 rpm.
For comparison to other Willard 30's. I also have a very clean hull with fresh bottom paint and keep it moving all summer, usually have a light slime buildup in the fall that pressure washes right off. FYI

You had a sea trial before haul out and bottom survey?

Hard to say what is the normal speed, not knowing the gear ratio or prop dimensions, but cruise speed at a given rpm certainly is affected by water conditions.

I have a similar hull to a Willard 30 and was cruising at 10 knots @ 2500 rpm a few days ago. I turned around and struggled to make 2 knots against the current.

AusCan,
They all have 2.57-1 BW gears and an 18" dia prop. At least those w the old Perkins.

You can actially get 10 knots? 100hp would'nt bag 10 knots on a Willard.

Eric,
Running with a 5 knot current, I'm sure Willy would hit 10 as well.

But of course. I've actually bettered that by one knot.
I just assumed you meant SOG.

SOG is with current like VMG. Usually GPS derived nowadays.

Speed (speed thru water) is without.

Many cruisers I know set engine(s) RPM for a certain "speed" and accept what they get SOG. Common in my experience pre-GPS as "Set turns for XX knots" and is adjusted after actual SOG/VMG is determined and adjusted further from there.

Out of curiosity, how many travelers actually have a speedometer that functions at displacement speeds? I sure don't! I just know what my speed through the water is based on my rpm's and experience, and what my speed over the ground is. I totally rely on my chart plotter and GPS for that information.

AKDoug said:

Out of curiosity, how many travelers actually have a speedometer that functions at displacement speeds? I sure don't! I just know what my speed through the water is based on my rpm's and experience, and what my speed over the ground is. I totally rely on my chart plotter and GPS for that information.

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After about 5 decades of sailing before switching to power, I still had a Knotstick in my bag of tricks. Just out of curiosity, one day I deployed it to know how fast I was actually moving through the water. These are very accurate up to 9 knots. My 2-way GPS averages of SOG were dead on, although often skewed by several knots in either direction. The trick is averaging them and making the runs close enough together that the wind and tide don't vary much. I prefer slack water on a calm day for this.

They are still in production and available here for anyone interested.

AKDoug said:

Out of curiosity, how many travelers actually have a speedometer that functions at displacement speeds? I sure don't! I just know what my speed through the water is based on my rpm's and experience, and what my speed over the ground is. I totally rely on my chart plotter and GPS for that information.

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I don't, but I have "should speed" based on the RPM. Then it's easy to tell how much help or harm the current offers.

Produces 6.3 knots through water:

Many " boat speed" claims are based on the fact most inland waterways are measured in Statute miles , not Nautical miles.

Most GPS let the operator choose , and once in statute the speed and fuel use look about 20% better so the owner claims its performance in Knots.

Caviat emptor!

The "normal cruising speed" of a boat is just what the owner normally cruises at, not a fixed number. One would hope it's at or less than the hull speed but some folks might cruise a bit faster with a pretty big penalty in fuel use.

My boat is about this size and as a rule, I run at 2000 RPM giving me 7 knots over ground. This translates into anywhere from five to nine knots depending on the tidal current in my usual cruising grounds.

I have seen as low as less than 4 knots and as high as over twelve knots in certain situations.

Each boat is different of course but if the speed is so slow the seller is making excuses, it should be checked out before purchase.

7 knots speed....SOG (speed over ground) is the speed you get when influenced by current/wind.

I agree with FF...some claims are often flagged by others as just no way....a lot of times I agree. Having run hundreds of different kinds of boats as a delivery and marina captain....just no way are some valid. Maybe reported as mistakes...but probably not all.

WesK,
Since your information in your avitar space is quite skimpy I don't know what kind of boat you have so 2000rpm and 7 knots is a hard pice of information put to use.

AKDoug said:

Out of curiosity, how many travelers actually have a speedometer that functions at displacement speeds? I sure don't! I just know what my speed through the water is based on my rpm's and experience, and what my speed over the ground is. I totally rely on my chart plotter and GPS for that information.

Click to expand...

New Moon's Simrad fishfinder has a speed wheel that is easily calibrated. I've found that the correct calibration depends greatly on my speed. So I calibrate it to be correct at my normal cruising speed, 6 knots. As a result, at higher speeds it can be wildly off, but then the GPS SOG is more useful.

Comparing the GPS-reported SOG with the fishfinder's speed relative to water, I get a handle on the current I'm traveling in. Of course If I'm crossing the current diagonally I don't get the current velocity correctly, but the information is nice to have, especially when more directly with or against the current. One challenge is that I have to clean barnacles from the speed wheel once in a while, even though I've painted it with transducer anti-fouling paint, which does help.

Given the LWL and displacement of a Willard 30, it would seem that the boat should cruise comfortably at around 6 knots (still water speed relative to water) on less than an gallon per hour. Seven knots speed would involve a lot more engine rpms and a significant fuel penalty. Without knowing the details of the power train (engine Hp rating at wide open throttle, wide open throttle rpm rating, transmission gear ratio and prop details (style, number of blades, diameter, pitch and disc area ratio), you can't really say more.

Seven knots is WOT on Willy..

manyboats said:

WesK,
Since your information in your avitar space is quite skimpy I don't know what kind of boat you have so 2000rpm and 7 knots is a hard pice of information put to use.

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Camano Troll. It's either 28' or 31' depending on if you're renting a slip or bragging. 10.5' beam, supposedly "semi planning". It will go 13 knots at WOT if I remove all the stuff my wife has added over the years.

Actually, the owner's manual suggests establishing an initial WOT speed and then seeing if that speed can be reached from time to time as a test of the bottom, running gear and engine.

As for the OP's low speed, engine problems can have an effect on speed as well as the running gear and bottom condition. Simple things like restricted air or fuel flow as well as more complicated issues.

To the OP if your boat can not make 6k+ (average gps speed) with and against currant in light wind and little wave action then yes some thing is wrong. The list of possibilities has been laid out in previous posts. good luck let us know what you discover.