Water Depths

[sailorob]

Hi everybody. I have an 8 metre sailing boat with a lifting fin, which I hope to sail on the Broads this summer. She draws just under six feet with the fin down, a little over three feet with it up. The only info I've found so far about water depths relates to 'chart datum'. I know that the Broads waterways are tidal. My questions are :

Can anyone give me a rough practical guide to what water depths I can expect to find at representative locations along the main three rivers (Bure, Yare, Waveney), and in Broads on or by these rivers ? I don't expect a hydrographic survey ( ! ) just a general practical guide. 

What tidal ranges (springs and neaps) can I expect on each river both near the sea and as far upstream as is navigable ?

I realise that this may be asking a lot, but advice from people with first hand experience would be very gratefully received.

And finally . . . how much should I expect to pay to have a holding tank pumped out ?

Thanks ! Rob.

[CambridgeCabby]

Whilst cruising the northern rivers I find the depth very very rarely reads above 6ft, as an aside is your mast easily droppable ? Due to the various bridges 

[BroadAmbition]

And finally . . . how much should I expect to pay to have a holding tank pumped out ?

Anywhere between £12 and £20 per tank depending where you go to, what day of the week it is, what your name is, wx dependent 

Griff

[BroadAmbition]

Fin down at 6ft on the Yare and Waveney you should be fine, even at low water unless its a proper low and some clown has pulled the plug out

Bure, again at 6ft you should be ok even all the way up to Coltishall.  At 3ft the rivers are all yours to explore

Griff

[ChrisB]

I am sorry, but I can't post a link but The Broads Authority web site has a section called " Water Depths and Navigation Notes" 

This is expandable, by continuing to click on the green river name and then the river setion you will get a proper Hydrographic Survey. These are PDF downloadable and will give you a proper set of "Charts" for where ever you wish to navigate.

Example:- Acle to Upton

 

[grendel]

https://www.broads-authority.gov.uk/boating/navigating-the-broads/water-depths

[RumPunch]

I've clouted the bottom pretty hard at Irstead - I draw a metre

[TheQ]

Tide, Normal conditions.. At Acle bridge you are looking at 18 inches level tide change at most, Increasing all the way to Yarmouth where you get a level change of what ever there is at sea. By the time you are at Horning or Potter maybe 6 inches to a foot depending on springs etc..

Really Exceptional conditions very rarely a 3 ft tide change as High as Horning or Potter. 

That's Northerly wind, Spring tides, high rainfall, raising the water to a foot above many quay headings, Switching to a southerly wind, no rain  lowering  the water levels to 2 /3  foot below quay headings.. 

 

You say Keel up, your draft is 3 ft , is that still sailable? or is that withdrawn into the hull?

Whilst draft is one thing ..

How good is your boat at tacking?

For instance sailing from Acle Bridge to Potter Heigham  with a northerly wind would require a tack every 30 seconds to a minute for 4 hours...

If you have only a big genoa, that would be a handful, not for nothing are most Broads equipped with what today would be called a "Blade Jib".

26ft is a nice length for broads sailing, many broads cruisers are longer than that, you should end up like the 40ft plus broads boats sailing a continuous swerve from one tack to the other..

There is a lot of useful information on here..  http://www.thegreenbook.org.uk/

Particularly in the Green book section.. Inside the green books site..

 

Oh do you now roughly when you come and get confused by us?

[Cal]

Our cruiser drew 3ft and we never had a problem with water depth anywhere on the Broads.

 

In fact it made for a nice change whenever we visited to not be clouting the bottom all the time 

[TheQ]

Just noticed my bad typing.. that should say " you shouldn't end up like the 40ft plus broads boats sailing a continuous swerve from one tack to the other"

[YnysMon]

There's a chart on the range of rise of fall of tide at the various bridges and a few other locations on the Broads here:

https://www.mynorfolkbroadsboating.co.uk/norfolk broads bridge clearance.html

 

[oldgregg]

1 hour ago, RumPunch said:

I've clouted the bottom pretty hard at Irstead - I draw a metre

Yeah, I remember a couple of years back loads of people were phoning the BA in digust to report an obstruction in the water and a load of signage was put up.

Of course it was just the river bed and the BA aren't going to be touching that because it's a natural feature.

[grendel]

probably why its called Irstead shoals, and has I recall a depth gauge on the approach.

[RumPunch]

I was that curious as it's the first time I'd hit it, I went down next day in the canoe with a metal rod and poked around. Yep - just the bottom and an unusually low tide

[Nickwaiheke]

I think the blade jib is a good idea maybe even setting up a self-tacker if you can. 

The one bit that caught me out badly as a newbie under sail is that Wroxham broad gives the impression of a good open space for sailing but the top end has a huge amount of weed in it, can slow you down quite a bit!

[TheQ]

It is an unfortunate side effect of having cleaner water, in the 40+ years I've been sailing here the water has got cleaner and the weed has got thicker.. The river From the Swan Inn, Horning upriver past Black Horse broad is now lined with water lilies, pretty to look at but it ends your race when you get one wrapped round your rudder..

[sailorob]

Thanks a lot, everybody, what a helpful bunch you are.

I noticed a few questions, so for clarity : My boat is an MGC27 with the self-tacking headsail (she has a normal genny too but that's for sea sailing), I foresaw the problem of tacking single-handed along a fairly narrow river ! They are reputed to tack (and sail) like witches, I'm looking forward to that ! Believe it or not (long story, won't bore you here but happy to send an email to enquirers !) I've not yet sailed the boat and have only seen her in photos ! Yes, I know !

The fin swings up under the keel, that's what gives the slightly-over-three feet draught. So all the weight is still outside under the hull. I shall very tentatively see what happens when I try her with two slabs down and the fin up, and if she feels as if she's about to fall over I shall chicken out VERY quickly and drop the fin !

Thanks to those who sent me the links to the BA depths maps (not really charts ?) which are very useful, I've downloaded the lot and converted them from .pdf's to .jpg's for easier sliding between them on my computer screen. I hope and trust that they're on the pessimistic side, and they do say their depths are at Mean Low Water so there's hope for my <6ft draught with fin down. Sad about shallow Rockland and Bargate (Surlingham) though, I'd like to overnight there sometimes. Maybe I'll let the fin do the soundings, I haven't much faith in the depth sounder over soft mud. I believe that the fin swings up when grounding, so the stodgy tiller should give due warning that it's time to go somewhere else ! Deep fin = higher pointing and better tacking ; can't have everything.

The mast is a lofty (for the loa) 38ft tall which, plus the 5ft of height from water to step, gives an air draught of about 42'. That's the boat's only feature which isn't Broads friendly. But it really makes little difference, once you have a mast you have to lower it for the bridges whatever its height. Would have been nice to be able to slip under Postwick, though. I've designed a fairly simple deck-mounting collapsible sheerlegs which should enable me to deal with lowering the pole singlehanded (VERY carefully and slowly, but who's in a hurry ? Bring your beers and come and watch/laugh, I don't mind !). Sure, I'm nervous ! However, being stuck in france due to Covid, I'll only have half of the summer for sailing and I'm not going to waste it on boatbuilding. She's in a marina at Brundall, so I'll be satisfied with toddling up and down the Yare until next year. If 'They' manage to fix the Haven and Mutford bridges, I'd be able to 'go round outside' and explore the Waveney too, but of course all the 'proper Broads' are 'up north' ; pleasures to come next year, when I should be able to drop the pole and sneak under bridges at low tide. Anyway, they tell me it's more peaceful 'down south'.

As for the cost of pumping-out ; well, there are other ways involving plastic bags to avoid pumping a loo, and as I'll be on my own I can put up with them. I'll find the cheapest, become a 'regular', and pay up when I must. Well, that's the theory ; I've lived in some primitive parts of the world ! Reasonable conduct, respect for others and the waterways, and general discretion seems to be the way on the Broads, as it is everywhere else.

Thanks again everyone, looking forward to 'bumping into' some of you !

Rob.

[grendel]

the rivers down south are for the most part wider too, and that 38 foot mast will get above the trees to catch the wind (some of the bigger broads racing yachts are even taller.)

[sailorob]

Grendel, thanks for that. Having been reading a lot about sailing on the Broads, I was hoping for the advantage of the mast's height which you've mentioned. There has to be some benefit . . . ! But being rusty after a longish gap in my lifetime's sailing, I shall probably lose that advantage at first because I'll be playing chicken and feeling my way into this new-to-me boat with a couple of reefs down, shaking them out as my confidence returns. I'm not a racing sailor, to me racing in sailing is similar to the famous saying that a game of golf merely spoils a good country walk ! Oh well, to each his own. The MGC27 is (it seems) renowned for its speed, which to me just equates to nice handling and a responsive boat. The speed itself doesn't bother me, but I'm sure that'll change after I've spent too many windless afternoons waggling the tiller trying to 'scull' home ! Anyway, I don't INTEND ever to be in a hurry, I want a peaceful life. H'm, here's an anecdote which may amuse you ; sitting at our yacht club bar one Sunday evening may years ago, after having annoyed the one-tonners by weathering and head-reaching (rather ill-manneredly) through their racing fleet in a thirty foot Van de Stadt cruiser ; one of their skippers came over and asked (rather sourly) why we didn't join the races officially ? I said "no thanks, apologies, but we never race". He said "So you never find yourself sailing in the same direction as another boat near you ?  . . " Point taken, it's sometimes difficult to resist the urge to twitch things a bit in those circumstances ! Your remark about the wider rivers in the south is also very encouraging, thanks again.