Thames Sailing barge

[Kimosubby ShipyardsParticipant @kimosubbyshipyards]

I've noted some talk re the lee boards.

It's all a question of scale, as you half the size you quarter the area and 1/8th the volume. If you follow that through you can then see that at 1/24 scale the area of the effective leeboard is too small to operate effectively. I have the leeboards working on the Theresa Mary, up and down depending on tack, but the keel is still required to stop excessive leeway. Making bigger leeboards alters the whole visual impact of the barge, they'd look like the flippers off of a hump back whale!

Paul understands, ask him.

Kim

[Bob Abell 2Participant @bobabell2]

Thank you, very much Kimmo

Good information, you have a good working knowledge of Bargeology!……Not bad for a Manxman!…..lol

I`d like to put the motor in the correct position, hey, Paul? and heed Kims Komments too?

Nice pictures, Kimmo…..Nice to see that toy keel weight works!……Even the big weight is looking rather small?

Keep popping in, Kimmo and keep us in order?

Many thanks…..Bob

[Colin BishopModerator @colinbishop34627]

The further beneath the hull the weight is, the less heavy it needs to be, Kim's boat is clearly a happy compromise borne of lots of practical experience.

Colin

[Bob Abell 2Participant @bobabell2]

Thank you, Colin

It may be possible for us to get away without a drop keel

If Kimmo's boat can sail with so little ballast, our boat being twice the size, that should improve our chances?

It should be great fun during tests

Bob

[Bob Abell 2Participant @bobabell2]

Paul

Since the hull is only 7" at mid point, are we shooting ourselves in the foot with the water ballast option?

Bob

[Amy jane SeptemberParticipant @amyjaneseptember49770]

Hi Bob.

Water ballesting only works on shallow, beamy hulls. A tank each side in the bildge, The windward one is lifted clear of the water as the boat heels, and becomes heavy, the leeward one is submerged and becomes weightless.

When I was 14 or so, I built an 8'x2' flat bottomed, undecked punt. With my 100lb butt sitting on the bottom, she would hold up 70 square feet of sail in a 10 knot breeze. How about using several lumps of removable ballest?

Shall keep watching with interest!

Aj

[Bob Abell 2Participant @bobabell2]

Hello AmyJ

With the water idea, it wasn`t used as ballast!

The hull was simply a plank of wood floating on the surface……The side walls were for appearance only

This has been the source of confusion all along!

We`ve always has a weighted keel to oppose the wind in the sails

The whole idea was to construct a large boat that didn`t require the usual 100lb of lead

Paul has moved the goal posts, where we need a device to launch the boat………(This may be our downfall, actually)

So, this mornings suggestion was to go back to conventional ballasting

Did you realise the workings of the original initial intention?…..If so, we would appreciate your opinion…..and any one else`s please?

Bob

[Amy jane SeptemberParticipant @amyjaneseptember49770]

Fair enough Bob.

I've re read the entire thread, and you can tell me if I'm understanding this right.

Original idea. hollow box raft,floating on the water, with the rest of the hull hanging below it, flooded with water, just to allow the hull to sit low in the water, with out it being too heavy out of the water. a fixed ballest keel to hold every thing up right . Yes? It would work, though you would result in a hull that required as much power to move through the water as one that was weighed down in the normal manner, but none of the righting power of the normally ballested model, resulting in much less ability to carry enough sail area to provide the required power.

[Bob Abell 2Participant @bobabell2]

Thank you, Amy

Pleased that our idea has some merit and you have understood the theory……..Please accept your well deserved promotion to …………Captain!

Would be nice to see how a big liner model would handle the idea?

Bob

[Kimosubby ShipyardsParticipant @kimosubbyshipyards]

Some more from that Manx Bargee!

Hello Bob, some technical stuff, but simple.

The keel weights as used by me, the red heavier one (on a longer fin for deeper water) used in strong winds is a Marblehead lead at 3.6Kg. The blue lighter one is, by looking at it, about 1/4 of a IOM lead (2.4Kg) which probably makes it only 1 1/2 lb max. [I'll go up in the attic and weigh it soonest.]

Here's the barge with the red keel on and in "coastal trim" (no bow sprit.) The two keels are below too.

Now I've also added a picture of the rudder extensions used. I mentioned this before. As we sail empty barges there is very little water grip of the rudder when sailing. It is possible to motor without the extension. Rudders from my two barges, note different styles.

You've been on the AMBO website, so know we've have several build guides and have had discussion also about where the keel/fin needs siting and even does a model barge actually need one. All good stuff.

I'll try and get some engine layout and shaft alignments copied for you on the next posting, Kim.

[Amy jane SeptemberParticipant @amyjaneseptember49770]

Thanks Bob

Promotion gratefully accepted!

[Bob Abell 2Participant @bobabell2]

Thank you Amy and Kimmo for the barge info……..I like the striped rudder!

Your keel weights are very light, for racing no doubt?

I had mine well down and sluggish, as I like to see the sails working hard with plenty of water wash etc

I sent you a message a few days ago regarding a chap called Doug somebody, you may have over looked it?

Bob

[Paul TParticipant @pault84577]

Since the hull is only 7" at mid point, are we shooting ourselves in the foot with the water ballast option?

Bob

You are the one creating the confusion……its a free flooding hull and the object of the exercise is to test whether or not a free flooding hull can be used for a large sail powered model.

The ballast required for a free flooding hull will be less than a traditional hull as we don't have to overcome buoyancy but we will still need a significant quantity of ballast to counteract the turning effect of the large sail area.

Paul

[Bob Abell 2Participant @bobabell2]

Paul

I just noticed you'd shown ballast in the hull and added 2 +2 and got 5!

So we are back on course then?

Bob

[Kimosubby ShipyardsParticipant @kimosubbyshipyards]

Sorry Bob,

I hadn't noticed your message. I've put out the feelers for info on the barge and new owner for you.

If you think my keel weights are light, some of the regular barge "racers" (there's a series throughout the summer) use a lot less dependent on condition on the day.

Congratulations on your promotion Amy, (I'm still before the mast!) sorry Mam'm!

Kim.

[Bob Abell 2Participant @bobabell2]

Shop floor to Drawing office

I don't suppose many readers can imagine that your barge drawings are actually FULL SIZE!

That's the beauty of Cad!…..It could also be a tiny dot and also as big as England!….and infinity!

How about a work in progress picture?

A 3D layout would be interesting?

BTW…..Joyce has spotted my error…..Predjudice?

Bob standing in the corner

[Paul TParticipant @pault84577]

Bob

Sorry but there is no progress since the last posting and we are a long way off doing a 3D layout.

Paul

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