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Thompson 750, canting keel


BvanVugt

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Hey

Anyone know anything about the Thompson 750's

Theres one on Trade Me which has been modified for a canting keel, does this sound like a good idea or a waste of time?

Anyone sailed a regular one, or know the owner of any that i could have a talk to?

Regards

Byron

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did a season on one called honk n jack, owned by jk on here. good fun boats and that canter one looks like a machine. would go very well! looks like the guy really knows what hes doing and has certainly done it well. quite envious of all that black stuff actually

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There has been a fair bit of discussion on SA about canting keels on sporties. From what I understand if you want to go fast you are much better off reduceing the bulb weight to the point where the boat will still self right and put wires or racks on boats 8m and under. This is inline with boats like animal biscuits and helter skelter. The canting keel will still work but won't be as fast as the above boats. On a 30ft+ keelboat boat where the racks etc are not a option the canter is the way to go.

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Unless of course you combine the whole lot.

 

I suppose though, there is significant danger of a big ole canting / canarding, racking, trapeizing, clusterfuck though!

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Maybe put a DSS in there to just for giggles.

 

With the canting keel you get more RM but at the expense of drag and weight from a bigger bulb and drag from a canard. With wires or racks you get the RM without any additional drag or weight.

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But interestingly enough the non trapeze Thompson 750 has beaten the trapeze one almost everytime they have lined up? Maybe too much righting moment so carrying too much rag and its all drag?

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To be fair Marshy, Atomic do sail very well and deserve their 11:3 winning margin & I would consider we were doing well if we could be competative against them. Against the other T750's we have wins of 6:1 & 4:2 against two & 3:4 & 2:5 against another two, so fairly even. I would tend to agree though that sometimes it is too much rag that does the damage.

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We built a beer ballasted 21ft sporty back in the day, along with a few others. The beer ballasting didn't work out that flash, the crew just got too pissed and the boat fell over. But then we morphed it into a multi use machine as 'The Man' and YC's back then were very very anti-sporties.

 

We had 3 bulbs we could swap in about 10mins on the beach. One for on the bum racing i.e. the slow sh*t most others were doing. One was a multi use and the small one was just enough to stop the boat falling over by itself when moored. It also had 4 traps which weren't used when doing official races.

 

Way way faster with minimum bulb and wires. A very significant difference and one hell of a lot more fun. I doubt that boat with a canter would have been anywhere near as quick, nothing like it.

 

As a FYI, that boats designer is the same one that drew up the Mini JH is playing with now. Mark 'Sooty' Stevens, the faster streaker on the North Shore at the time, or at least that's what the Policeman who finally managed to catch him told the Judge :lol: :lol:

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Wonder why it keeps popping up for sale - interesting to see if it sells at anywhere enar that price considering a few other T750s have sold for less than that and they were complete and in sailing trim.

 

Heres an idea I've been wondering about:

This size boat which is right on the cusp of being big enough to do longer races like Simrads and Coastals, as well as bight perfect for sportboat racing. Could you set it up so that for round the harbour sportboat racing you have four wires and the keel is just set in the middle (as you don't have time to fluff around with it) but for the longer stuff where you can't use the traps, you use the canting keel?

 

Does the underwater stuff for a canter work when its not canted? would you have to sail around with canard down to get the balance right?

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Sounds like an interesting set up with the canting prod let alone the canting keel. how do you think would it go against you high n Fibre? Your idea of using it for the larger races sounds like a good one and im gutted that I dont have the money for it as I like sports boats and would have loved to have brought it up to Auckland :D

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Wonder why it keeps popping up for sale - interesting to see if it sells at anywhere enar that price considering a few other T750s have sold for less than that and they were complete and in sailing trim.

 

Heres an idea I've been wondering about:

This size boat which is right on the cusp of being big enough to do longer races like Simrads and Coastals, as well as bight perfect for sportboat racing. Could you set it up so that for round the harbour sportboat racing you have four wires and the keel is just set in the middle (as you don't have time to fluff around with it) but for the longer stuff where you can't use the traps, you use the canting keel?

 

Does the underwater stuff for a canter work when its not canted? would you have to sail around with canard down to get the balance right?

 

 

Pretty much exactly what im thinking.

 

Id have no idea what it would be worth at the moment. If it was in Auckland id go take a look and chat to the seller considering i missed out last time.

 

Coastal is cat 3 which needs life lines doesnt it? so that could be an issue, but things like simrad and the other harbour courses would be cool.

 

Looking at the chord length of the keel, its a little shorter then the standard T750 one, but probably not enough to make enough difference to warrant sailing with both the keel and Canard if on traps. I guess you'd just end up trying both and seeing what worked best.

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The canting prod is stock standard for most of the Thompsons. The idea is it gives you more options for deep running but it seems that sportboats are so slippery that with the right genny you can sail just as fast a VMG with a fixed prod - can't hurt to have one though although the rotating arangement/forestay attachement point must add some weight up there.

 

The T750 are a very quick boat and are probably still the best all round performer of Sportboat fleet when well sailed. Atomic is consistantly well sailed and is more often than not the gun boat on Wednesday nights.

 

Sportboats are all about weight vs sail area vs righting moment - the T750 are at the heavier end of the sportboats but they are very wide (most have bolt on wings that add about 300mm to each side that basically get the crew as far out as the trapezing boats that don't have wings), have big sails and have powerful hull shapes. On a good night we can keep up with Atomic now that we have added 3 trapezes - which means we need a fourth trapeze!

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Very slightly off topic, but does anyone know what happened to the Sheldon designed modified Lightning 7.5 Astro-Traveller?

 

When I owned her, we put triple wires on, and to be honest, aside from power reaching none of us really noticed much difference.

 

Upwind we were still matching the garden variety 30 footers, downwind nothing even came close.

 

On the only occasion we dragged her down to Aucks, we missed our start by about 5 minutes, and four or five hours later we finished a similar distance behind three Magics and Pria Pism.

 

That was about the year 2000. I lost her in a financial flop late in 2001.

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