Guessing your current speed (Hire Boat)

[cuthound]

I use Ulysses Speedometer (an Android app), because it has a slow speed mode. In deep water (for a canal), say 4 feet deep, 1000 rpm is about 2 mph, 2000 rpm just over 4mph.

 

Note that shallower water results in less spped over the ground for a given rpm.

 

However, all boats are different, so speed will depend on prop size, draught, length of swims etc, there is no hard and fast rule.

I generally cruise at about 3mph, and drop to just above tick over a couple of boat lengths before I get to a moored boat. Not had any speeding complaints using this technique yet.

 

Edited to explain the the speedometer is an app.

Edited April 23, 2015 by cuthound

[Cruising Mike]

Well, clearly im not savvy when it comes to engines, but i presume that the 1, 2, 3 and 4 on the RPM dial represents 1000, 2000, etc. Correct me if im wrong!

 

In the last boat when it was on '3' there only a mild wash.

[Athy]

Well, clearly im not savvy when it comes to engines, but i presume that the 1, 2, 3 and 4 on the RPM dial represents 1000, 2000, etc. Correct me if im wrong!

 

In the last boat when it was on '3' there only a mild wash.

There you are then. They've fitted a Hotpoint dial by mistake. Those numbers refer to wash cycles. For goodness' sake don't put it on "5" or the boat will spin and tumble.

[ditchcrawler]

The Broads Authority are considering insisting that all hire boats are fitted with speed indicators.

[bottle]

Well, clearly im not savvy when it comes to engines, but i presume that the 1, 2, 3 and 4 on the RPM dial represents 1000, 2000, etc. Correct me if im wrong!

 

In the last boat when it was on '3' there only a mild wash.

 

You are correct in your assumption but it may have been faulty because 3,000 rpm is basically revving the guts out of the engine and is its maximum.

 

For you information have a look at this PDF it is for a Beta 43 (which is not the 'standard' engine in hire narrowboats but very similar).

 

You will note its maximum rpm is 2,800

 

Again are you talking about a narrowboat on the canals or some other type of hire boat??

[BruceinSanity]

Another vote for the Garmin eTrex for the reasons given. The time when the speed over ground is most use is on the tidal Trent, when a reduction in speed for the same revs strongly suggests you are about to hear that dreaded shushing noise from under the bottom...

[Naughty Cal]

Another vote for the Garmin eTrex for the reasons given. The time when the speed over ground is most use is on the tidal Trent, when a reduction in speed for the same revs strongly suggests you are about to hear that dreaded shushing noise from under the bottom...

Or the tide has turned

[blackrose]

My boat will do about 6.5 mph flat out at 2,150 rpm in open water as measured by a GPS android phone app. No idea how accurate it is.

[David Mack]

Last time out, we used the RPM dial to approximate our current speed. Eg: 2000 RPM, aprox. 2-2.5mph.

A hypothetical point in our case since our engine has a maximum speed of 1000 rpm.

[Guest]

Just time yourself between 2mile markers on nicholson's (etc) map. You'll soon get the idea of what speed looks like what.

Done this a few times. My boat rarely seems to exceed 3.5mph on canals. More revs just means more fuel, but does tend to keep the batteries up when the washer is on. the boat feels quicker at higher revs, but is just more noisy and digs its back end in; the actual speed increase (iphone or measured distance) is minimal. Different on wider deeper waters.

[captain birdseye]

Making a breaking wash = going too fast, not making a breaking wash = not going too fast (when not passing milder boats). What more do you need to know.

[BargeeSpud]

I didn't realise there were more than one - its the Google one, if it makes the difference? Try this, might have worked as a link:

 

https://play.google.com/store/apps/details?id=com.google.android.maps.mytracks

Brilliant, thanks very much.

[RichardH]

We were asked this many times. Simple answer was 'first notch on the morse when passing boats' and 'don't break a wash anywhere else' Speed is fairly meaningless if the canal is so shallow you scrape the bed.

[Machpoint005]

I have a 20 year old splat nav designed for walking. It is very nearly useless, but it does tell me my cruising speed -- usually about 2.7mph on shallow Northern canals, equating to 1100rpm.

[Athy]

A hypothetical point in our case since our engine has a maximum speed of 1000 rpm.

I was thinking along similar lines - ours will reach only 1,700 rpm, thus any attempt to get it to 2,000 would surely bring unhappiness.

Is yours an RN?

[alan_fincher]

I'm staggered that many hire boats need to be at anything approaching 2000 rpm to make normal progress - 3000 rpm just sounds beyond belief.

 

With the boat we have just sold, (BMC 1800), then about 1,400 was typical for a sensible maximum on the shallower canals, maybe 1,600 could be used without wash on most of the broader deeper ones, and at about 1,800 on a river you were starting to cane it, with no benefits of going higher.

 

If a modern (or modern-ish) engine in a narrow boat is regularly at 2,000 rpm or more, then I would say that in general something just ain't right, (even if it is no more than the tachometer being wrongly calibrated - they do have to be calibrated, to give a correct number - twiddling a small adjuster in one is a guaranteed way of giving a false reading).

[gazza]

Another vote for the Garmin eTrex for the reasons given. The time when the speed over ground is most use is on the tidal Trent, when a reduction in speed for the same revs strongly suggests you are about to hear that dreaded shushing noise from under the bottom...

I've been using our etrex as a depth sounder for ages, just as you describe! As soon as the speed drops off for the same revs I know the bottom is getting too close to the top! Particularly handy across the middle levels which varies from shallow, to really shallow with the odd surprisingly deep bit for good measure.

 

Now the 50 year old stern gear has been replaced and we are Wash ready I shall be fitting a proper depth sounder

[Alan Saunders]

When I hired boats (1976 -1995) it was important to keep the crew (relations and friends) happy so that we could visit waterway attractions; a historic house for some and a pub' at lunchtime/evening for others. Sometimes I ran with a 'barely breaking wash'. Of course, there was always the requirement to return the boat to the hire-base on time.

 

As an 'owner' I meander along at 2mph and try to wave faster boats by. If a stoppage prevents me from reaching my mooring I can leave the boat moored on the towpath and return during the week to move it.

 

I have never had a boat that cruised fastest on a canal at much more than half maximum rpm. On the Thames I managed 5mph between markers at maximum, 3,000 rpm, but it was very noisy and probably not deep enough to reach the maximum hull speed ~7mph.

 

Reduced rpm, minimal bow wave = faster progress. Although I now have an Android 'phone I do not need it it to optimise my speed.

 

Alan

Edited April 23, 2015 by Alan Saunders

[FadeToScarlet]

Yes indeed George, as suggested in an earlier post I think.

 

Then again, when the offside is very shallow, especially if it's stony, you can make a breaking wash even when you're going very slowly. There's nothing much you can do about that unless you come to a complete halt!

I can make a breaking wash at tickover when going through The very shallow bit behind the rotary club, just Long from Chateau Athy.

[David Mack]

I was thinking along similar lines - ours will reach only 1,700 rpm, thus any attempt to get it to 2,000 would surely bring unhappiness.

Is yours an RN?

No, a National. But a very similar engine.

[markgregoryuk2000]

Always ask the hire company when you pick the boat up.

 

4 MPH has usually been between 1600 and 1800 RPM

 

Unless you are hiring something strange, 4mph at ~400RPM (shakes the boat a bit) but that is a single cylinder diesel with a max RPM of 500

[Sabcat]

I've not a clue what rpm my engine is doing. Tickover and the boat moves very slowly, about one third throttle will give me the maximum speed on shallow canals, any more and I just make more noise, more smoke and burn more fuel. On deeper water I can get half to two thirds throttle if it's wide enough and I'm guessing 4mph or maybe slightly more. The only time I ever go above two thirds throttle is in reverse because I want to stop in a hurry. The engine is a Lister ST3 spinning a 19x14 prop on a 62ft Colecraft hull.

 

I'm one of those annoying boaters that's never in a hurry, don't worry though,if you are I don't mind getting out of your way.

[spadefoot]

Blimey, I go along at 900-1000 rpm but revs versus speed is non-determinable in a fluid. As many have said already, actual speed is irrelevant but simple maths can give you the answer. 4mph is 5.86 feet per second, 2mph is just under 3 feet per second, If you know or can measure your cabin roof length, then as the front of the roof passes into the shadow of say a bridge-hole, start counting. When the back of the roof hits the shadow, stop counting. My roof is 43ft so less than 7secs & I'm speeding, about 14secs it's 2mph. If it's not sunny just think a bit, 4mph will take you about 10secs to pass a 60ft boat etc. If it's raining or late on a Bank Holiday Monday, obviously you're allowed to go as fast as you like.

[nicknorman]

I'm one of those annoying boaters that's never in a hurry, don't worry though,if you are I don't mind getting out of your way.

In that case you are not in the least bit annoying. The annoying ones are those who think anyone wanting to go 0.1mph faster is a reckless speed freak and it is their duty to hold them back, for their own good. Whilst of course anyone going 0.1mph slower is a dullard who should be confined to a marina.

[Cruising Mike]

In that case you are not in the least bit annoying. The annoying ones are those who think anyone wanting to go 0.1mph faster is a reckless speed freak and it is their duty to hold them back, for their own good. Whilst of course anyone going 0.1mph slower is a dullard who should be confined to a marina.

 

I was stuck behind someone on the stretch before Barbridge junction. A good hour or so or moored boats, but my the guy in front was taking the biscuit. And, i have to say, he not once looked back to acknowledge us.

 

As for the other comments, i'm surprised. Because i swear the dial had 4 numbers on it, and for the most part we cruised just shy of 3000. But this goes back to my point in my original post. If this sounds crazy and excessive, which it turns out to be, then perhaps we were going too fast. I always tended to go just fast enough (in open water) without creating a breaking wash, and it just happens so that just under 3 was the right point of reference.

 

Yes, on a narrowboat. I wouldn't have asked if i wasn't ready to learn anything.