Todays Boating

[Richard BarnettParticipant @richardbarnett67129]

Hi all,

The sails for the Gull turned out well, still in the middle of setting them up but as it’s dry I dragged it outside for a photo shoot (see album)

The picture of me with it was to give the sense of scale, which is tall! When I was building the hull I shortened it by about 3inches so it could have been bigger. I do tend to make a rod for my own back.

Catch up with you all soon and Happy New Year.

Ricky ye pirate (rigging cord and bowsies)

[NoelParticipant @noel26080]

Happy new Year to everyone and must say the Gull looks fantastic and very tall

Over Christmas have stolen the odd moment to paint and rig my Dab Chick which is now nearly ready.
Finished radio gear install last night and now only have the main sail left to rig.

bath test due though to work out how far she can heel before the hatch covers are put to the test!

Noel.

[Richard BarnettParticipant @richardbarnett67129]

Noel, I’ve been considering a winged keel, size and angle of attack would have to be considered but it would negate a bucketload of lead, thoughts anyone?

Ricky ye pirate

[Paul TParticipant @pault84577]

Richard

A winged keel is a wonderful idea for getting more lift and therefore more speed but I can't see how it can replace the ballast mass that lead provides.

Paul

[NoelParticipant @noel26080]

wouldn't you need a tremendous forward velocity in order for sufficient downforce to be created by any wing?

[Ray Wood 3Participant @raywood3]

Hi Richard,

Here is the winged keel for my sailing barge, moulded from GRP weight 6 lbs of lead poured into the wings before the 2 halves are joined with a 6mm stainless rod bonded in with P38 filler to the top. the barge is 42" X 10" beam with a lot of sail area, and I think performs better than the original fin keel on the right, and it makes launching and recovering much easier at the pond side

Regards Ray

[Richard BarnettParticipant @richardbarnett67129]

Paul,

Depends on the angle of the wings and the size if angled down they would pull the hull into the water. I’ve had some success with this on a sailing boat I once had that kept nosing in when sailing in front of the wind, so I put a small wing on the end of the rudder with a very shallow angle and it sailed well after that.

Ricky ye pirate

[Richard BarnettParticipant @richardbarnett67129]

Ray,

Thanks, that’s food for thought !! I knew somebody would have thought of this before.

Ricky ye pirate 🏴‍☠️

[NoelParticipant @noel26080]

I see now. Shorter keel also less likely to get snagged on any of the giant sea monsters (carp) at Bushy!

[Richard BarnettParticipant @richardbarnett67129]

You’ve read my mind Noel!

[Ray Wood 3Participant @raywood3]

Hi All

The wing section is fully symmetrical not an Aero foil lifting section most popular in full sized shoal draft yachts like the Spring 25 which with it's twin rudder can dry out and sit on the putty. Side area increased to equal the same as the fin keel.

Regards Ray

Not to be confused with a foiling keel, which is meant to fly, no ballast involved, like an international Moth

Edited By Ray Wood 2 on 03/01/2019 17:23:36

[Paul TParticipant @pault84577]

Richard

I am confused, which I have to confess isn't difficult these days, I understand the physics of a keel wing providing lift and proving useful in helping prevent the craft for nosing in but unless the wing is made from lead how does it stop a crosswind from blowing the boat over.

Paul

[Ray Wood 3Participant @raywood3]

Hi Paul

The wing is full of lead or concrete to keep the righting moment.

Regards Ray

[Richard BarnettParticipant @richardbarnett67129]

I seem to have started a bit of a discussion here, I like your wing keel Ray that would work well on the Galleon and my Gull. It’s a bit shallow round the edges of our sailing pond so that would be a ideal solution to an ongoing problem.

Ricky ye pirate (lead moulds and burnt fingers) ha ha!

[Tim RoweParticipant @timrowe83142]

I may be able to help a bit with this discussion.

Until very recently I owned a Jeanneau 28i with a winged keel and this boat was designed by Tony Castro who was also the designer of the Spring 25 mentioned by Ray. In a cruising yacht the main purpose of the winged keel is to obtain a low centre of gravity coupled with shallow draft. Again Ray mentioned this benefit. In terms of ballast, a winged keel can be though of as a highly distorted bulb where the function of the bulb is also to lower the centre of gravity. A winged keel is definitely not a substitute for ballast and if you tried to achieve a righting moment using a wing ie dragging the windward side down it would create so much drag as to be self-defeating.

A shallow draft keel generally has to have a wider chord (ie distance from front to back) in order to maintain the required area making it low aspect ratio. Low aspect keels are less efficient than high aspect keel at the speeds we are talking about and therefore to compensate, a low aspect keel might have larger area than its high aspect sister. Here is where the wing keel does have an advantage and that is, that when the yacht heels, the wing automatically presents a large projected area as the tip of the wing is now below the centerline of the keel. This helps restore some of the efficiency. Try sketching it on a piece of paper.

The full sized 12m Australia had a winged keel which was literally shrouded in secrecy before, during and after the races. Extensive tank testing proved the wings to be effective and particularly at reducing drag from the tip vortex of the relatively low aspect keel which was a function of the rules. A debate still runs today as to how relevant the wings were in achieving victory because in every other respect it was a brilliantly organized campaign. They would probably have won without it anyway with the keels but it was a great psychological coup.
The really fast yachts of today have such skinny keels as to wonder how they stay in place, with a torpedo type bulb for the lowest centre of gravity coupled with resistance (wave form drag) and wetted surface (parasitic drag)

Confusion can arise because keels and rudders are actually foils and are sometimes called by that name. Because a yacht has to perform equally well on both tacks the keel and rudder have to have a symmetrical section. Leeboards are an exception because only one is used at a time.
Foils used in a more horizontal plane create lift that can take the hull clear of the water but to find some examples, motor hydrofoils do not require ballast to counter the effect of wind heel from sails, the Moth type dinghy uses the weight from a very fit helmsman and the large sailing catamarans have widely spaced foils as well as using crew weight.
Going back to Ray's barge I can understand the wing keel working better. It is (with respect) not a high performance sailing yacht. It is unlikely to point very close to the wind and therefore cannot take full advantage of the high aspect deep keel. These high aspect keels have very little lateral resistance when stalled and a boat will move sideways very quickly if stopped. The more "barn door" like shall winged keel is more tolerant in this aspect and I suspect better suited to the barge design.

I am sure I am guilty of some topic drift!

Tim

[Richard BarnettParticipant @richardbarnett67129]

Thanks Tim, I remember all the hoo ha about the Australian 12m Americas cup race winners winged keel and I’m not surprised it’s still rumbling on!

I was thinking of a winged keel for the Gull as it’s not going to win any races but it’s the stability with a shortish keel is what is needed.

Ricky ye pirate (lumps of lead scratching head)

[Tim RoweParticipant @timrowe83142]

Hi Richard
Go for it and try to get as much lead as you can in the wings. Maybe all of it and use some other material for the vertical keel.
Tim

[Ray Wood 3Participant @raywood3]

Hi Richard

Some debate on another thread here about securing a removable keel, can you drill a hole in your existing keel for a brass tube up to deck level? For the studding and a wingnut , making a plug and mould for the keel is quite a chore I used a plaster of Paris which worked sort of but was broken during the efforts to release the halves of the keel. Dave Watts of Mastman makes various vac formed abs plastic bulb & winged keels which can be filled with lead shot & resin maybe worth a look at his website .

Regards Ray

[Richard BarnettParticipant @richardbarnett67129]

Hi Ray, I’ve got 10lb in two 5lb half’s bolted to a thick alloy drop keel as a test weight as it hasn’t been sailed yet, as with all new boats a period of trials is always needed.

I’ve allowed for alterations in most areas.

Thanks for the tip for Mastman, will look them up.

Ricky ye pirate

[Richard BarnettParticipant @richardbarnett67129]

Hi all,

Wetted the Gull’s hull this morning, looks great but kept running aground as the keel is a bit too long for our pond. So a winged keel now is definitely on the cards, I think it will work well as Gull is very beamy so it already has good stability.

Nice to have Ashley back with his new polished eyeballs along with our other regulars.

Ricky ye pirate (thermal socks and waders)

[Dave MilbournParticipant @davemilbourn48782]

A very pleasant and successful morning here, too.

I finally got to throw the Swordsman into the water up at Papplewick Pumping Station and he/she/it didn't disgrace him/her/itself. Performance is stately and scale-like although there was an annoying rattle on occasion from the rear bearing, probably due to a paucity of grease and/or an oval bearing. Solution is to add more grease – and buy better prop shaft assemblies in future! I'm blowed if I'm going to dig the prop tube out of this model when it will almost certainly spend the rest of its life as a static model on SLEC's stand. Now the one I'm keeping for myself is a different matter…

Still – "Onwards and upwards"! All I have left to do is draw the final plans, check the parts shapes for the umpteenth time, select the photos and schedule the parts list, write the text for the instructions, add the text to the photos, blah blah blah….. I sometimes wonder if you folk out there appreciate the slog that goes into producing a kit, even though we now have CorelDraw, AutoCAD, MS Excel and Word and Adobe Photoshop to help. It's a good job I've had a little practice too!

Dave M

[Colin BishopModerator @colinbishop34627]

On sale next month then Dave…

Colin

[Paul TParticipant @pault84577]

I sometimes wonder if you folk out there appreciate the slog that goes into producing a kit

Slog?

I thought that you had a computer………so all you have to do is decide what size / style and press a couple of buttons

[Dave MilbournParticipant @davemilbourn48782]

See? I was right!

DM

[ashley needhamParticipant @ashleyneedham69188]

r

Hi fellow boaters, pic still u/s but on the Mrs I-pad,,, I may purchase something a bit bigger as this is a bit small for surfing. Happy new year to all etc. Eye op all ok, am using Poundland reading glasses to read, pending proper eye test in five weeks. Can't seem to tab down for a new paragraph…? as I now have a balanced view of the world (,) I can revisit the London and see how wonky I have made it. Hoping, given the shenanigans of the dove keel that my ideas in this direction will be ok. Driving again, so am off to wickes soon to get more ply to complete London mast-box. Sunday very pleasant boating. Project z going well. Will soon have to make decision about which boat to "out" in the mag. Ashley

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