Jump to content

Wash In The Rivers


Recommended Posts

unfortunately its not as simple as the v shape, it comes down to the whole hull shape, and theres no denying that the old wooden boats still produce less wash as a rule than modern fibreglass boats.

i believe a lot of it is the shallow draught near the stern on wooden boats that reduces the wash

  • Like 2
Link to comment
Share on other sites

I believe a lot of it is the shallow draught near the stern on wooden boats that reduces the wash

That's correct, on displacement craft if a stern below the waterline sweeps up to a very shallow draft or even sweeps out and above the water (A lot of yachts do this) then it reduces drag hugely and as a consequence reduces the stern wave created,  If the beam also curves/sweeps narrower to the transom with a curved / rounded transom this again helps.  On the downside all this reduces the interior space available.

The worst sterns/transoms for creating drag and a stern wave are those that have a guillotined straight cut off shape to the stern.  On the plus side this gives more interior room.

Planing & deep V hulls makes no difference as the transom dries out once on the plane and the large wake is caused by the bow wave and the 'Rooster' tail which shows a visible inefficiency btw

Boats always have and will be compromises in their design

Griff

  • Like 2
Link to comment
Share on other sites

When Herbert Woods built  Lights Boats along with Brooms and Powels building and design they own  Boats  they were very popular Wooden Boats on the water and they are  still are to this very day  but having Fibreglass Boats are not as good of the Wooden Boats that was built in the Sixties 

Link to comment
Share on other sites

1 hour ago, Smoggy said:

Most of the time they seem to be at speed when not rescueing anyone as well, are they exempt for that?

No, and that was from a BA ranger. 
The rowing clubs near us use Seastrike dory type boats for safety. They are ok if 2 up but when only a single helm they are inclined to sit with half the boat out of the water and produce a bow wave like a swim head barge.

Colin :default_winko:

Link to comment
Share on other sites

At Horning the club drivers are reminded they can't speed except to an actual rescue, though some people need reminding more than once.

One of the problems with them is at low speed they make so much wash, they appear to be going faster than they are. 

The other problem on a down river race the the competitors are faster than the motorboat speed limit at times, and you are supposed to stay within viewing distance to see if there is anyone in trouble..

Link to comment
Share on other sites

23 hours ago, grendel said:

i believe a lot of it is the shallow draught near the stern on wooden boats that reduces the wash

It is quite noticeable that the old woodies just glide through the water with hardly a ripple and you can see the shape of the stern even sometimes slightly out of the water. Its a shame this hull design is not incorporated in GRP hulls on inland craft.

  • Like 2
Link to comment
Share on other sites

 

From what I would call true Broads boats, those with a Wild's family of hull seem to be the main culprits for excessive wash when at speed. Against that though they provide the most practical shape to maximise space in a 12' beam craft and some good looking versions (the centre cockpit Alphas come to mind) have and still are being produced.

Not so much speed but a very strong incoming tide at Stokesby causing wash from an Alpha version of these hulls.

Fred

Fighting a strong flow at Stokesby.
Link to comment
Share on other sites

The Hickling saftey boat came past today doing 10-12 mph causing a huge wash on what was already a choppy day on Hickling, had to turn into it to ride it in a small boat the best I could, was picking up the marker buoys at the end of the day an emergency?

Link to comment
Share on other sites

43 minutes ago, Bernard said:

The Hickling saftey boat came past today doing 10-12 mph causing a huge wash on what was already a choppy day on Hickling, had to turn into it to ride it in a small boat the best I could, was picking up the marker buoys at the end of the day an emergency?

No it wasn't and deserves a warning at the very least, it's just another motor boat causing problems for every one else.

  • Like 1
Link to comment
Share on other sites

1 hour ago, kpnut said:

Not rocket science. 

That may be so. But I’ve sat and watched the very minimal instruction that is given from someone stood at the back. Then they untie the ropes and tell them to go. It’s no wonder some dayboats behave as they do. 

  • Like 1
Link to comment
Share on other sites

Whilst I accept that the bigger beasts that may need to punch the current on the lower reaches and need a bit more throttle these dayboats around Wroxham  and Potter do not need that sort of power and the speed limit is much lower in those areas. 

All that is needed is a collar or the like clamped onto the throttle cable down in the engine compartment to limit the speed.

As that ruddy meercat would say.......simples!

 

  • Like 1
Link to comment
Share on other sites

even restricted in engine size the dayboat will always create more wash, its down to displacement speed, and boat length. being shorter the displacement speed is lower, so they are trying to climb the bow wave, which is what causes wash, that and hull shape.

Link to comment
Share on other sites

16 hours ago, Bernard said:

The Hickling saftey boat came past today doing 10-12 mph causing a huge wash on what was already a choppy day on Hickling, had to turn into it to ride it in a small boat the best I could, was picking up the marker buoys at the end of the day an emergency?

I've passed on your remarks to someone in Hickling SC, to be passed to their Authorities.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Sponsors

    Norfolk Broads Network is run by volunteers - You can help us run it by making a donation

×
×
  • Create New...

Important Information

For details of our Guidelines, please take a look at the Terms of Use here.