As I have said I purchased an old Tiger Shark cat to attempt a steady 25 knots in outright speed. This boat is 18 feet long.
The mast was 29 feet high and Have cut that don to the hounds and a little off base meaning it is now 24 odd feet.
The original sail has been cut down to a square top and the foot is also a lot shorter.
I have raked the mast like a Hobie 16 and took the boat out for its first run yesterday. The wind was approx 12/15 knots. I went out with two Hydra 16. The Tiger is still faster than those boats but easily controllable by one. It was twin trap.
Top speed yesterday was 15. The main is very flat and I was running the full height old jib at present. I expect to cut that back away from the beam.
At 15 knots boat speed the Hydras were starting to push the nose down and work hard. The Tiger was fully planing and not showing any sign of heeling or nose heaviness.
This is a very rough back yard affair and I now ask for any ideas for trim etc as I finish the tuning positions for gear etc and I start to up the wind speeds.

Finally the idea for cutting the rig was that in the 25 knot wind condition I expect to need for the speeds wanted I will not need all of the extra sail area. I also have 5 feet of useless mast and sail I don't have to drag through the air.

Attachment shoes boat in its old rig. New rig photos when I have them.

Good looking platform, I always like hulls with chines. I would be surprised if you can get to 25knots but its certainly worth a try. I did some similar stuff to junk Cherubs and skiffs years ago, amazing what can be built from a yard full of old boats.

Raking the mast moves the centre of effort aft but it also reduces the max draft of your sail as the airflow changes so if your short on power and not nosediving try raking it forward of your H16 position.

I would try the jib in higher winds first before cutting it down, all that sail area low down is really going to help.

Good luck with your project,

Darryn
1782

weather helm might become an issue with the mast raked far back too.

very interesting project

where are you in the bay?

that looks a little like what i remember of matauwhi bay, by the reserve, or are you somewhere else entirely?

looking forward to seeing some pics with the new rig

Here is a photo yesterday out at the islands. Not Matauhwi. Out in Parakura near Rawhiti.
No weather helm at all! The tiller is as sweet as I have ever experienced, quiet and light.

put a spinny on that beast and then I bet you'll be able to get her up to 25 knots in that wind. Its possible to get up to that kind of speed in any boat I would assume, but you are going to need a nasty storm with some sick winds, and a heavy crew. Keep us updated though on your progress! This kind of stuff gives me something to look forward to while I let the snow slowly melt away up here.

looks like larger paper tiger!!

Now we know what happens to paper tigers when they grow up. <img src="http://www.catsailor.com/forums/images/graemlins/grin.gif" alt="" />

My top speeds have been 25.3 knots on the F18 and a little less on the inter20. That was only in bursts though. Without spinnaker too. I think that a spinnaker would collapse at 25 knots boat speed.
A sustained 25 knots is a big ask for any boat.
All the best.

I had decided not to attempt Spinny for that reason.
I decided on this rig after watching the Tornado guys on you tube going for top speeds. They only managed 22 knots and spent most of the time trying to manage luffing out power. They had too much power not too little.
I am hoping the mast rake helps with keeping the nose up, the lower mast with center of effort and not dragging so much stuff through the air at that speed and the V creating a steady plane.

But tell me, how did you have the boat set to achieve that speed?

Speed-wise, rake has very little, if any, influence, and it may even be detrimental. But if it looks good to you...

I've got "old school" standing rigging (read WAY less mast rake) on our H16 because we don't race the boat and use the boat primarily for what you're doing. While rake significantly helps pointing ability, IMO, it only hinders all other points of sale. Our stick's straight up compared to race position for beam/broad reach speed trials.

We travel the jib all the way out, travel the main out 1/3 to half way, trying to find a main traveller position that will allow one arm's length of gust dumping ability and not stuff the bow. Carving up and down the puffs to maintain a constant speed is difficult, at least on the 16, because you can't look over your shoulder, or behind you, to see the puffs coming for fear of stuffing the lee bow, you just have to react. Depending on wind speed (and for you to get to 25 knots) your crew weight will need to be between 450 & 550 pounds. How will you keep a double trapped crew on board? We use a line from the stern to prevent crew falling forward in a stuff (chicken line) main concern would be is your crew experienced enough to find the right trapeze height and agility to not be washed off when slammed by a wave at that speed. Also crew needs to anticipate major and quick course changes to avoid pitching in puffs and in order to maintain control of the boat I've found I cannot trapeze and maintain balance. I'm at the rear corner steering, eating water, trying to maintain vision.

Best of Luck

Set up the rig so that it can be tilted to windward - like a windsurfer. The Catapult has this facility.

Raking will reduce power. Why would you rake it in an attempt to increase speed?

The main looks a bit worn out in order to get it really flat. You might want to try with prebending the mast as well as applying lots of downhaul. You also want thee mast rotator to be ajustable to get almost no rotation, i.e. a VERY flat main. At high wind speeds drag from the rig is the most important factor. The T has a highly ajustable rig, which your shark doesn´t seem to have (yet?).

Thanks for all of these comments.
Mast rake is not for speed but to help with reducing healing moment. As I explained the boat has heaps of power, too much for really high speed.
The sail is an old one cut to shape. It is very flat. I will do practice runs first to make sure new sail is worth while. I will also go to a broken A class carbon fiber mast so I can induce pre bend and lose weight. The boat is foam core and was 114 Kgs new.
I particularly appreciate the Hobie experience of actually going out there for speed alone. What speeds have you logged?. I will take that info with me.
As I have said I have used it once. Yesterday sailing at 15 knots boat speed in approx 15 knots of wind was okay as a start. I was hiking, not trapping and only one up and controlling the boat easily. I would crew when really trying to go fast. My crew will be just a tiller man. The main problem was the fullness of the jib and the way it was set as I had spent two days fitting the rig and ironing the most basic of problems.
This is really about the hull shape guys. I opened my mouth here to say that planing is worth working into the late model boats and so I am just playing with that.

Also, the rig idea to pull the mast over, yes, I have thought through that and might go there but I wanted something that could relate to buoy style sailing.

Also, I wasted the Hydras downwind yesterday so I am not feeling downwind has been so adversely affected.....but I was planing and they were starting to stuff.

Does it actually, really, truly plane? If so, that would be very exciting. <img src="http://www.catsailor.com/forums/images/graemlins/ooo.gif" alt="" />

Wow, is that true? I had the original ply version that was used to make the mold for the glass boats (what I was told at least). It's a long time ago but I think it was a whole lot heavier than my Blade.

Warbird,

That is a great looking boat! The squaretop just looks right. Have you considered a full batten jib? One of the reasons a H16 is such a reach-monster. I love projects like this.

Also-
You might want to consider a Hooter type sail. We plan to use one on our next boat and it is an old flat reacher from an E-Scow. Looks like a genoa more than a spinnaker- so fast at tight angles. Roller furled for ease of handling.

Much easier to push around than my Hydra and my Nacra 14 sq.
I can bend down grab the gunnel and flip it on its side easily without busting a foo-foo valve.