Dr. Sam Bradfield

Dr. Sam Bradfield has passed away. He was an inspiration to me and helped me learn a lot about hydrofoil sailing design. He had a way of explaining hydrofoils in a simple straightforward way. Sam designed an improved version of the wand surface sensors that regulate hydrofoil altitude. His basic system was copied and improved by John Illett and other Moth designers. After one summer where he used a trimaran platform of mine to test concepts for the 40' Skat, I designed a 56" radio controlled foiler, the F3, and a 16' monofoiler based on what I learned from Dr. Sam. He was an innovator, teacher and a great man.

Here is a page about him from foils.org: http://www.foils.org/bradfield.htm
Dr. Sams company website: https://sites.google.com/site/hydrosail/HydroSail-Home

Here are just three of his boats, the 16' Rave, 40' Skat and the 18' Osprey.

 

Dr. Sam

This article was edited a bit and appeared in Professional Boatbuilder-here is the unedited version:

http://smalltrimarans.com/blog/?p=8890

 

Wording for flying Trimarans in the boat markets...

Tks DougL ! - I go into this topic "foiling Trimarans" here.. .related to your comment about foil-assistence....

Indeed... you are right. I missed the correct word. Tks helping out.

It is as you say: "traditionally Trimarans" which have a weak uplift in the bow section of the amas/outriggers/floats can benefit mostly from the "new foiling era" to get a tool for compensating this weakness as seagoing vessel...we are in now since the hype started in 2013 by America's Cup media coverage.

Not just seeing from technical side... it will be tricky for the future and it will demand from all activists in the world of Trimarans a very sensitive handling - by marketing and correct wording. Otherwise it can ruin the future of bigger Trimarans.

Alain Thébault made it very clever in time to address his "flying experiments" under the own name Hydropter (French: L'Hydroptere). So he keeps himself in a uniquely standing and niche, avoiding the risks of confusion from media side and consumer (which would have a very negatively effect for successfully sponsorship).
So he wont be mixed up with all the other "flying attempts" on Catamarans, Monohulls, Trimarans, Kiteboards etc....

I see this as a big challenge these days: How to position the "traditional Trimarans" in this new era of "flying objects" ?.

Foil-assisted Trimaran sounds terrible... technically the correct term. But it cannot be communicated in marketing/advertising to sell new (foil assisted) boats.

Imagine the Danish warft Quorning Boats is announcing a new Dragonfly with the slogan: "here is the new foldable and foil-assisted DF 37". Cant work... sounds like a "sick patient".

"Assistance" evokes in the brain of consumers (potential boat buyers) a negative anti-pathy. Something like: He needs via****** to have fully sexual potentials.

Not funny... imagine a boat owner is asked in the bar of a sailing club: What are you sailing ? And he has to answer: I sail a foil-assisted Farrier F39. So bad....

As you know, Gitana is doing successfully its "foiling assisted MOD70" tests for the new Maxi Trimaran they are building with launch in 2017.



More details here: https://trienthusiasts.wordpress.co...ti70-trimaran-within-a-series-of-test-phases/

How shall we call these boat types in the future with a "sexy wording of correct classification" ???

- traditional Trimaran (without foils, mainly with central daggerboard)
- foil-assisted Trimarans (with L-Foils to give more uplift for avoiding nose diving)
- foiling Trimarans = flying Tris like we see it with Dr. Sam's 40 footer Skat
- hydrofoiling Trimarans = Hydropters with hydro-foils.

Very confusing... this form of segmentation "traditional, foil-assisted, foiling" is something good for the history books and technical departments, but nothing to attract the new "foil assisted Trimarans" to the public.

One thing I demand from Trimarans generally... that they will be the fastest boats on planet earth (beside Alan's radical Hydropter which sails in an own league). Trimarans had this image now since the 90th... and its their coolness to have this image being supported by their radical look having 3 hulls.

I suppose technically there is no other way around than giving the new Trimarans of the future a package of foils to keep the speed record marks against the foiling Catamarans. As it can't be (and may not be) - as it is for now unluckily - that a 80 Foot Trimaran (without foils) is overhauled by a 60 foot G4 foiling Gunboat Catamaran. Wrong world...

As said... it needs the right wording. I have no idea yet how to call "foil-assisted Trimarans" in the closer future. I am working in medias and as cultural journalist... so we have to crack our brain cells for creating something which keeps more easily in the minds of people.

 

DougL: Do you know what happened with Dr. Sams company HydroSail LLC since 2012 ? Is there a new ownership and team who keeps the spirit and work alive ?

And what happened with the boat 40'Skat ? Is it still on the water ? I have not found one single video of this beauty.

There is only one short snippie of Dr. Sam's EIFO Hydrofoil
Very blury.... https://www.youtube.com/watch?v=b0R7kxOEQ9g


I really love what I see with the EIFO test (already done in 2008 !!!!)... the boat is not jumping out of the water, or pitching heavily and uncontrolled... it is moving slowly and steadily from water surface to flying status continuously accelerating... and keeps very low over the surface... thats amazing, very elegant and "makes sense" to speed up.

For me sailing is an esthetically joy, too. Boats must be beautiful... elegant, well balances in their lines... and how they move through the water. Very important.

So I can imagine to see bigger "foiling Trimarans" in the future that way... differently from Alain's L'Hydroptere. And many people will enjoy it by sure.

The movement of EIFO looks very safely... its not that one gets scared watching it and saying. This boat is too fragil, it is not balanced, too risky. I have the confidence, that bigger Trimarans moving like EIFO will find many buyers and boat lovers. No doubt about this.

Why this concept didnt progress since 2008 and became more present to the public ? One answer probably: Engineers and technicians dont care about marketing. They mostly focus on technical problems, working on solutions, testing... maybe it lacked of a good marketing specialist in Dr. Sam's team ????

 

Jay, SKAT was sold to the Navy and cut up and shipped to them. I'm not sure whats happening with HydroSAIL. Dr. Sams shot at mass marketing was the 16' Rave.....
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I don't feel the same way about "foil assist" as you do-I think it's a perfectly logical term for describing a boat that doesn't fully fly but does use foils.
Macif and Gitana are no longer "foil assist"-they are out and out full flying foilers! My personal opinion is that they'd do better with one central rudder T-foil along with their UptiP ama foils and an altitude controlled T foil* on the daggerboard which would guarantee flying in lighter air and more consistently.

* a surface piercing T-foil would work if they didn't want downforce from the foil.

 

T-foil on a daggerboard...

ah... interesting. I haven't thought about this alternative as I cant remember a Trimaran using a T-Foil on the central daggerboard. Remembers me the "fin keels" with rudder of former America's Cup era (attached a more radical solution: The tandem Twin keel. Really crazy concept being used by the AC class in 1992.)

Where I get some more infos about such a T-Foil pimped (central) Daggerboard ?

A T-foiled central daggerboard would be helpfully for elder Trimarans, isnt ? Or is it only for some new ones like the Gitana or Macif mega-maxi tris ?

I ask seriously, as the 40 Foot Trimaran I am negotiating about (actually neither I can name here the designer nor the name of the boat) needs a new daggerboard and rudder, so the designer adviced after a long skype video conference I had this week.

Generally I like that idea to optimize an elder Trimaran being built 20-25 years ago with tools like foils, T-rudders, Daggerboard, rotating wing mast.

Many elder trimarans have the problem that they no more can be competitive with traditional bow forms as the pitching effect becomes extremly slowing down the boat heavily. Am I right ? (Sorry, if I should ask some silly questions. I have a technical engineering background (but I am not a naval architect).)

"traditional bow"


"Reverse bow for wave piercing"

 

I heard about, that they want keep the door open for both options:

1. Sailing the Maxi Trimaran solo (e.g. for circumnavigation)... without radiacally foiling/free flying as it is too risky, so probably then only "foil assisted".
   
2. Sailing the Maxi Trimaran with bigger crew... and then fully foiling and all 3 hulls flying, going onto the limit of the boat to be competitive in short distance race circuits

We will see in 2-3 years, if this "compromize" can be done. Maybe they just use different shaped foils, some with lower uplift effect, and a pair with more radically uplift. For now it seems, they decided for the L-shape foil as the tests with the C-shape havent been very promising.

 

Jay, the only trimaran in the world ,that I know of, using the altitude controlled foil on a daggerboard is my 5' test model. The advantages are numerous, but primarily much greater pitch control with the rudder T-foil and daggerboard foil working together and the ability to fly the main hull in very light air-way before it would do so because of wind pressure-and the fact that the main and rudder foils would control and maintain the angle of heel of the whole boat. Secondary advantages include the fact that as soon as the main hull flys, the main foil begins to unload, reducing drag. And a wand controlled main foil could also develop downforce if desired which would increase RM(-and also increase structural requirements). The amas use fixed UptiP foils which maintain altitude with no wands or other adjustments-this Test Model was the first trimaran of any size to use UptiP foils in the amas that I designed based on the original TNZ foil used in AC34.
You can read more about the results so far in testing in the thread--the last two posts-- http://www.boatdesign.net/forums/mu...f-righting-trimaran-test-model-36058-144.html

Fire Arrow on July 24th, 2014-the day she first flew. This Test Model is a scale model of a 20' full size tri designed specifically for this foil system which will fly the full size boat in a 5-6 mph wind. The Test Model pictures were taken in a 5mph wind measured with a Davis Windmeter:

 

Hi Doug
Can you please reach me via the Questionnaire at www.smalltridesign.com.
Have a potential foiling project I'd like to discuss with you
thanks
mike/

 

Hi Jay
Although I know this post was 2 yrs back .. just like to add that the two bows you show are actually very alike. The W17 is by no means either old or traditional. It goes deep and there's no vee'd section up forward which would be traditional. The slicing bow wave creates minimal side displacement and no traditional 'moustache' that a Vee'd bow makes. Pitching with either of these bows is also lower. The W17 could make a good foiling platform if built light enough.
The M&M design is what I'd term an AXE bow ... a near vertical one with a slight curve. A reverse or wave piercing bow is typically far shorter on the deck. More on this in an article on pros and cons of various bow forms on my website or in SAIL article.
www.smalltridesign.com
best, mike

 

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Hi, Mike- I responded on the website-I think in the right place! Doug