260 2.5 efi wanted

[kiwiracer]

you will need sportmasters at that speed
cle's will blow out

[gar163y]

No they won't - CLE's will be fine.

[kiwiracer]

at over 90mph?

[roofer]

Guy I know did 109 mph down windermere on a 2 way record run with cle's and had no problems.

[Jon Fuller]

We ran 111mph on CLE's, but I have to admit, they were mounted high, tucked up behind the sponson, with little more than the skeg showing below the running surface. Just enough bullet showing for the nostrels to pick up water. (25' Puma cat)

[kiwiracer]

i wasnt trying to start an arguement, but there is a difference between setting up a boat to do an offshore race and doing speed runs in a straight line in calm water
john fuller has got it right
its just that we have found down here that above 90 in an offshore application sportmasters are more efficient
perhaps i should have explained myself a little bit better earlier

[Taz]

Originally posted by kiwiracer
i wasnt trying to start an arguement, but there is a difference between setting up a boat to do an offshore race and doing speed runs in a straight line in calm water
john fuller has got it right
its just that we have found down here that above 90 in an offshore application sportmasters are more efficient
perhaps i should have explained myself a little bit better earlier

I must admit sportsmaster boxes are on the list have to see if funds are there after the build.. Id rather have them then cle's but for the wrong reasen i like the look of them!

[gar163y]

I have never run a cat like you guys but in this application of a 21' monohull I did run a pair of CLE's on a Ring 21 in ski-racing for 11 years and never knowingly got close to a blow-out (I haven't even seen an anti-blowout ring for years).As the sportsmaster is fatter I thought it had a lower blowout speed. ps. I also have a fully shiftable lefthanded CLE box surplus to requirements.

[Burty]

sportsmasters have blow out rings as standard i think the 4hole cle's have too
plus sporty's are longer

[Cookee]

Got a 15" 2 hole CLE with 2:1 gears and a blow out ring on it for sale if anyone needs one?

[Matt]

How/Why does a blow out ring work?

[Jon Fuller]

I've always been intrigued by that. My understanding is, the lip increases pressure fwd of it close to the casing, which I guess keeps the space filled longer.
I suspect that once the blow-out occurs, the ring isn't able to recover the situation any quicker, as it would be pissing in the wind, probably just increaes the initial spead shreshold that blow-out starts at.

[Burty]

Originally posted by Jon Fuller
I've always been intrigued by that. My understanding is, the lip increases pressure fwd of it close to the casing, which I guess keeps the space filled longer.
I suspect that once the blow-out occurs, the ring isn't able to recover the situation any quicker, as it would be pissing in the wind, probably just increaes the initial spead shreshold that blow-out starts at.

TBH i don't think its anything to worry about because i can't see it happening in offshore conditions, you read about it happening on S & F but they are all little lightweight hulls with massive power running like 140mph on lakes.

[Matt]

Think Jon's right, can't think of any other obvious solutions.

Burty - When a boat hooks, is it the front or back end that's letting go?

[Jon Fuller]

The more modern lowers are infinitely better than the older style, shorter units.

Steve Baker experienced blow-out back when he was racing/setting boats up, and they wouldn't have been exceeding 80 back then, probably no more than 75.

The older ('87/'88) Bravo looks well short when compared to the models after that.
Nose cone kits were very popular with that stubby style lower, but I reckon you could probably run well into the 80's with a std, late Bravo.

We added a Bobs nose cone to our later style Bravo, and all it did was Fkk up the handling, as we weren't dragging the bullett through the water straight.

[Tony Davis]

Originally posted by Jon Fuller

Weaddeda Bobs nose cone

wot did we do?

[gar163y]

Many years ago Land & Sea offered kits to squeeze V6 gearboxes into straight six (for Mercs) or V4 (OMC) gearbox casings. Coupled with the right nosecone they claimed huge performance gains. Unfortunately together with the turbo, water brakes and nitrous they're no longer in the catalogue. Going off the thread a bit here.

[Matt]

Why'd do the B23's run such hugely long gearcases?

[Jon Fuller]

Originally posted by Matt
Why'd do the B23's run such hugely long gearcases?

I suspect (guessing here) they give a shed load more rudder, and subsequently, less likelyhood of a involuntary, instant 180 degree 'about turn'. ...you gotta luv them steps!! (not the teenybopper band, before I get any smartarse comments!)

[Matt]

But with such a rounded profile, wouldn't ya have though it wouldn't add much rudder effect - better to increase the skeg size a bit?

I was wondering if running it high it acts like a ski and adds loads more lift.