Driving Cat Tips

[Jaxson06]

Gents

Any tips and tricks for driving twin outboard cat?

Cheers

[rosco1974]

drive it like ya stole it the harder u go the better the ride,ya trim and tilt on the outboards work like trim tabs on a mono boat.

[fandtm666]

have fun going out for a fish then clench the butt checks coming home in a nice
following sea because they do like to broach ( well my brothers broadbill does )

[rosco1974]

2400 kelvacat doesnt broach at all neither does a 18ft bruce harris

[Stuart]

Rosco,

Your kidding about the Bruce Harris not broaching?

[rosco1974]

mate the 1 i have been in didnt so guess i can only go by that 1.just speaking from the boats i have been in...

[cormorant]

Gents

Any tips and tricks for driving twin outboard cat?

Cheers

Did you end up buying that "tom cat"? If the previous owner is a decent bloke it may be worth doing a run with him and now the money has all been paid having a chat about any bad manners.

Where do you live as you may b able to meet up with someone local and do a run.

Each type of cat rides differently and reacts differently to motor trim at different speeds.

Take it cautiously until you find out what it's manners are in various scenarios.

Have a search about "walking the cat" as it is one of the pleasures of a cat hull along with passing fair weather monos and still having a backbone.

[Pimp A Shrimp]

Plenty of trim in both a head and following sea. Almost to the point where cavitation kicks in, and then bring it back a couple of notches. My old 5.6m Barcrusher CC use to breach quite badly in a big following sea, however the current 7.0m OMM Jaycat is very sure footed. I find at WOT in glass conditions is when I tend to have some trouble. Usually one of the Hulls grabs a little when performing slight turns, hence you can't 'walk the dog' properly.

[cormorant]

Plenty of trim in both a head and following sea. Almost to the point where cavitation kicks in, and then bring it back a couple of notches. My old 5.6m Barcrusher CC use to breach quite badly in a big following sea, however the current 7.0m OMM Jaycat is very sure footed. I find at WOT in glass conditions is when I tend to have some trouble. Usually one of the Hulls grabs a little when performing slight turns, hence you can't 'walk the dog' properly.

If you have counter rotating motors try and throttle up your inside motor as you turn and it will stick both hulls to the water and keep it flat. If both normal rotation try it but I would only suggest it in one direction in poor conditions. Different hulls react differently, weight distribution and props can change just what trim and stern lift you end up with so you have to see how your hull reacts.

We all have different ideas of what is plenty of trim and my slight and your plenty may well be the same. Some hulls need more and other have strakes that do the work and keep the attitude of teh cat that way in any case.

Bit of debate about trim as different hulls react differently and so much is about feel in the helm seat in different seas. I have mates that insist on trim it up a lot burning extra fuel getting a nose up attitude and then the whole hull doesn't work and other cats like the full length of the hull working pretty much flat with the hull shape creating the small nose up attitude. Each is different and in different conditions let alone how well powered they are. That said you don't want negative trim or all sorts of bad habits can appear and bite you except for when you are trying to get out of the hole faster with a full load on. Then trim em in and get the whole hull taking some weight and trim it out as you get some motion.

[The Woo]

This is such a difficult subject to teach on a forum! haha (having said that, "walking the cat" is a good place to start and Webster's description of it is easily digestable).

Every cat I've been on is different, with some MUCh better than others in some situations. Heck, even the same model boats with differing weight distributions and power feel very different.

I WILL however say I've never been on a cat that when driven properly that was a broacher. In fact, most I've been on you could feasably walk away from the helm in a following sea, whether it be off the quarter or straight up the backside, they've been very surefooted.

[cormorant]

Í think Peter Webster still sells his powered cats of Australia vol 2 via ebay or his seamedia website so get in contact and buy a copy. All his stuff was always worth a read


Hey Woo

I was once officially told that Mr Bungy Cord is not considered a crew member on watch nor a mechanical autopilot.. How wrong they were!!:) . Ahh the days before fancy electronics and NFB hydraulic helms.

[nathan dumschat]

I would have to agree with the purchase of the Power Cats Of Australia book if your just starting to learn about trim etc theres some good pointers in there.As a rule trim out until you just start getting cavitation then just in until it stops. Worst thing you can do is trim in as cats are design to have the air in there tunnels. Ive driven quite a few broachy cats not a nice feeling and get your heart rate up. As you get more experience you can actually feel it happening through your feet ,its hard to explain. Never fight a cat as it broaches as the harder you fight the more it bits , just steer with it in the direction it is broaching and you can feel the sponson pop back on the plane then you can correct it. You cant learn things like this out of a book or by being told you learn by experience. Its not that hard, you just have to spend time in the saddle. Start off on the days that have good weather first up and you shall be fine.
Cats need the chop and are not at there best in glassed out conditions and in these conditions monos are probably better but as soon as the 10 to 15 knot starts they come into there own and leave the monos behind

Once you have had a cat you wont go back

Nathan

[Jaxson06]

Thanks heaps guys....will be taking her out for the first time this weekend...

How good is this site!!

Cheers

[nathan dumschat]

what breed of cat is she

[No Fear]

What a good thread! I am going to try and track down Peter Websters DVD as it sounds like a good learning tool. I have a single inboard cat and would be interested to know if there is any info on the DVD for these. Like others have said above, I just drive mine by feel. Only time I have felt it move sideways a little was in 3 meters of following sea in glassed out conditions. Felt weird but as Nathan said above, I just kind of went with it. Still could do with some additional tips and have wondered if trim tabs would make a difference. Maybe this DVD will teach me a thing or two!!

[nathan dumschat]

Gday No Fear

Does yours have a 200 hp Volvo If so would be excellent on fuel. I had a mate with a noosa cat with a single diesel that he used as a commercial spanner crab boat used to get 1 ltr/ nm at 20 knots which gave him a huge range, he loved it . A mates got a Noosa Cat with twin 130 yammy 2 strokes . He is using 2 ltr /km

Nathan

[No Fear]

That's right Nathan- I have the 200 hp diesel Volvo Penta in mine. Just put 2 x 280 litre tanks in there so range shouldnt be an issue.
I have just pulled the engine out and gave it an entire overhaul as it was pretty sad. Overhauled the injectors, fuel pump,put a new turbo on it, plus cleaned everything else up. Prior to the overhaul was cruising at 18/19 knots and burning about 1l for a bit over a km. Hopefully the overhaul should improve it plus looking at upgrading the Ali props to stainless, in the hope that will help it as well.
I think it's a good thing, just about heavy on the steering over 10 knots but I drive in straight lines anyway!!

[cormorant]

What a good thread! I am going to try and track down Peter Websters DVD as it sounds like a good learning tool. I have a single inboard cat and would be interested to know if there is any info on the DVD for these. Like others have said above, I just drive mine by feel. Only time I have felt it move sideways a little was in 3 meters of following sea in glassed out conditions. Felt weird but as Nathan said above, I just kind of went with it. Still could do with some additional tips and have wondered if trim tabs would make a difference. Maybe this DVD will teach me a thing or two!!


Not sure if he did a dvd but he did a magazine - well 3 that were listing all the cats sold in Australia and in between adds he added some stories, tips and history. Not sure if he does those issues as a PDF that you can buy off his website ( seamedia) or just sends out the paper magazines. He was headed towards electronic publishing I think. He has reviewed a fair few cats over the years as well.

[ozlongboarder]

I just searched the seamedia site but could not find anything. If anyone does find those articles please post a link to them.

Any other tips would be greatly appreciated.

Noosacat 3100 2x225 Opti's.

[nathan dumschat]

Sea media is on the net but cant find the link to Power Cats of Australia. There contact number is 55642562 during office hours . This magazine is worth chasing up.I think there up to volume 3 so far and well worth getting all of them

Nathan

[cormorant]

Just send him a email or phone him and he will sort you out with a copy. This is a pdf of the cover and contents

Because he is one of the only blokes who ever did independent reviews I won't cut and paste the contents as he sells his stuff cheap anyway and happy to see him get a few bucks.

http://www.google.com.au/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&ved=0CC8QFjAA&url=http%3A%2F%2Fwww.seamedia.com.au%2Fpublication s%2Fcovers%2FPUBCTN12.pdf&ei=2DxRUabAIIzOkwWOpICoDA&usg=AFQjCNHLhwBUUiNKvxMSSRPiraa3ouJCYQ&cad=rja

[The Woo]

Just send him a email or phone him and he will sort you out with a copy. This is a pdf of the cover and contents

Because he is one of teh only blokes who ever did independent reviews I won't cut and paste the conents as he sells his stuff cheap anyway and happy to see him get a few bucks.

http://www.google.com.au/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&ved=0CC8QFjAA&url=http%3A%2F%2Fwww.seamedia.com.au%2Fpublication s%2Fcovers%2FPUBCTN12.pdf&ei=2DxRUabAIIzOkwWOpICoDA&usg=AFQjCNHLhwBUUiNKvxMSSRPiraa3ouJCYQ&cad=rja
Absolutely. Peter's a great bloke, very helpful, and a wealth of REAL trustworthy information. My hope is there is someone he's trained in the wings to continue his work when he decides to hang up the cap. Is his son Jeff that guy?

PS. Page 104 of that edition features my Mum :)

[No Fear]

If anyone is interested, heres a email I got regarding the above:

I'm sorry we no longer have any copies left, but we do have a Cat Survey
supplement on line version.

If you go to www.boatmags.com.au (http://www.boatmags.com.au/) and go down to Consumer Reports you will go
into the correct site to download the cat supplement.

As a member subscriber it is free to download.

As a non member it is $9.95

A 6 month subscription to The Boat Mag is $29 which enables you to view
anything on the website for free and all the

emag back issues of The Boat Mag.

We attach a file to all our emails to make it easier for our readers to
navigate around the website and download the emag

( PDF) to keep on their computers forever and not have to go into the
website every time they want to read the

mag. Hope this helps.

Regards Mary Webster

[Captain Seaweed]

Well I thought I would fire up this thread again if that's ok as I have a few questions being a new cat owner...

I have just bought a 2680 Glacier Bay, its a semi displacement cat running twin 150's. I have a couple of questions.......

I was out in these conditions today and just couldn't get the trim right and would love your insight......

Conditions: 15Knot Northerly , I left Tangalooma and was faced with I rekon Northerly Bay swell 1.2-1.4m

I was running back to Manly and was running a little south west so I had a quartering sea and wind. I trimmed the port side motor up but found I was occasionally getting a roll up sponson to sponson, and also getting cavitation in the port side motor as it rolled so I decreased it but still would get the roll up occasionally. What could I have been doing wrong?
Port side trim- just below cavitation
Starboard- a little deeper than port
Speed- Travelling at 26 knots.

I played with trim to the point that the boat wouldn't sneeze also but ended up coming down a little as this would create more often the rock n rolling sensation.
I am very green when it comes to cats but I insist on learning. I did not have any bone shattering bumps along the way home and conditions were average.
*Boat has Doel Fins cavitation wings but I am looking at going Permatrims....thoughts?

I look forward to your replies.
Cheers
Marty

[rosco1974]

just sent ya a pm marty

[Captain Seaweed]

Thanks Rosco got it!

[cobiaman]

Drive it like you stole it and get some air under the tunnels!

Thats what i have learnt from ausfish...

[Muddy Toes]

Did you hit the wrecks at Tangas or is that just a mono owners thing ?

[Captain Seaweed]

I did try to drive it like I stole it and regret starting it with a screwdriver now...

No Muddy, didn't hit the wrecks, it would be hard to pull that off :)

However I did realise under anchor the cat gets a swing up, slow but swings a larger arc than the mono.

Not bad though, I do like it just need time at the wheel, otherwise its like a gypsy ride at a local carnival......exciting cos you don't know what will happen next!

Cheers
Marty

[hilta1]

I think you may have trimmed the wrong side motor up if i have read the conditions correctly,Basicaly remember if you trim the starboard side motor up will lift the port side sponson, so if the sea is coming from the rear quarter on the starboard side, you need the port side sponson to lift so you trim the starboard motor up,hope that makes sense. It has taken me a few months to get the hang of it but now wont go back to mono. Regards Mark

[johncar]

Without being there and I haven't driven a Cat for a few years, I am tending to agree with hilta1. I am imagining that the northerly sea is on your starboard stern which was probably picking you up and trying to bury the port bow. So if that was the case then you should need to trim out the starboard engine a little and trim the port engine fairly neutral.

Anyway where I had the room to navigate, with a Cat in a following sea on either quarter I used to avoid it like the plague and rather tack where ever I could, so I would get closer to square to the following sea, get on top of it, trim both engines out and get going, and then I would at the appropriate and safe time turn and run beam on until I could run at the more comfortable angle again. It worked for me anyway and I hated anyone driving with that rolling action you described.
I am sure you will get that sorted out. They are a different beast for sure

[cormorant]

You also get sponson loading alternately if the motors are toe out. ie the props are pointing in towards the tunnel and it changes the effectiveness of your trim. . I've always run my cats slightly toe in but you can tell a lot from the wake and motor wash. Others have various ideas on this. Set it up neutral for a start as it is easy to change as you will have dual cylinders hydraulic and have a 3 way link valve to adjust toe in and out.

I might be wrong and haven't driven that size Glacier but being semi planing don't try and trim up the bejesus out of it as it need the hull length and being really fine at the bow entry it will offer little buoyancy but once it burries itself a little it will lift . That is why they are known as soft riding, fine entry , pointy hull shape and very efficient on flattish and choppy water because of it. It will feel odd and sound different but try and let the hulls do the work with, water in the tunnel and change in hull shape as it gets burries a little will lift. That's my guess. Not like a mono where you trim up and try and get only the back third of the hull doing the work.

Not sure what fuel load you were running but dynamics change when running light with fuel and water tanks empty in a following sea. You won't have that issue when it is full of fish and ice!!!
Resist toughing the throttles would by my other hint. It is a weird noise in a cat hearing the motors work hard and then alternately hearing the hulls working and it is in stereo as the motors are separated by 6 foot not like a mono with dual motors next to each other but it takes a while to get used to the different noises and attitude. That said at different angles and speeds it does get uncomfortable and dangerous at some point when you have to start imputing too much trim and you know you are there when you get airation of props and the boat self steering on swells.

As a comparison to a shark cat that has fatter sponsons up forward and a fat flatish planing area at the rear of the hulls and they liked a bit of trim up to keep the bow up and make it a dryer ride if you had the hp to do so.

When you are used to it and are feeling safe I'd be interested if a single motor will plane you home or just bog down. ? I'm thinking it will with the other leg out of the water.

Last dumb comment . You Have counter rotation motors . Are they on the correct sides? I've see a couple rigged wrong in photos in the states

[Captain Seaweed]

You also get sponson loading alternately if the motors are toe out. ie the props are pointing in towards the tunnel and it changes the effectiveness of your trim. . I've always run my cats slightly toe in but you can tell a lot from the wake and motor wash. Others have various ideas on this. Set it up neutral for a start as it is easy to change as you will have dual cylinders hydraulic and have a 3 way link valve to adjust toe in and out.

I might be wrong and haven't driven that size Glacier but being semi planing don't try and trim up the bejesus out of it as it need the hull length and being really fine at the bow entry it will offer little buoyancy but once it burries itself a little it will lift. Absolutely correct, this is what I started to work out. Yes it is super fine entry That is why they are known as soft riding, fine entry , pointy hull shape and very efficient on flattish and choppy water because of it. It will feel odd and sound different but try and let the hulls do the work with, water in the tunnel and change in hull shape as it gets burries a little will lift. Your not wong about different noises!!!! In he mix you get slurping noises from the self draining deck holes that run up the sides of the hull!!! sounds like cavitation sometimes...use to it now That's my guess. Not like a mono where you trim up and try and get only the back third of the hull doing the work.

Not sure what fuel load you were running but dynamics change when running light with fuel and water tanks empty in a following sea. You won't have that issue when it is full of fish and ice!!!
Resist toughing the throttles would by my other hint I think I was trying to get the speed up on it to try and see the change, when I slowed to 23-25knots it did improve a lot. It is a weird noise in a cat hearing the motors work hard and then alternately hearing the hulls working and it is in stereo as the motors are separated by 6 foot not like a mono with dual motors next to each other but it takes a while to get used to the different noises and attitude. That said at different angles and speeds it does get uncomfortable and dangerous at some point when you have to start imputing too much trim and you know you are there when you get airation of props and the boat self steering on swells.

As a comparison to a shark cat that has fatter sponsons up forward and a fat flatish planing area at the rear of the hulls and they liked a bit of trim up to keep the bow up and make it a dryer ride if you had the hp to do so.

When you are used to it and are feeling safe I'd be interested if a single motor will plane you home or just bog down. ? I'm thinking it will with the other leg out of the water.

Last dumb comment . You Have counter rotation motors . Are they on the correct sides? My props are rigged with the left turning on the left and right turning on the right, if that makes sense...ie the port engine is counter rotating. I've see a couple rigged wrong in photos in the states

I have highlighted my answers in green..if it works!

[Captain Seaweed]

:-/ maybe green wasnt the best choice

[kock81]

hi captin seaweed
maybe you could slow down a little. Now i know, cat owners can't understand what language i've just used,
slowing down is a result of pulling back on the throttles a little. I know, i know, this will feel very foreign and may take two hands to over power the urge of of pushing forwards, this will be the first time for many but trust me it does work.
Doing 26knts when it is a bit snotty partically on the rear qtr is always gunna be hang on in a cat.
And before i get bashed about cats need for speed to get the tunnel going etc, roger that, but warp speed does not have to be the goal in all conditions.
Kock.

[Captain Seaweed]

Thanks Kock....Iv done 3 hrs in this boat and all is new to me. I am testing all theories out hoping to learn something new. Have you spent much time in semi planing cats or more so in planing cats? No need to shoot you down, not running for parliament!!!! just trying to learn, all feedback welcome

Cheers
Marty

[Grand_Marlin]

G'day Marty,

All cats have different traits.
Cats v's Monos, cats take some getting used to for a start.
Bigger cats like yours will have a completely different feel to Mick's 18ft Sharkcat and Rosco's 2400 Kevlacat.
Best bet is to get someone who knows cats to go for a run with you in that 15 knot stuff.... Try different speeds, different trims at all different angles.
Then you will see where the boat is happiest.You will also have someone who can verify if it feels right or not.
Be wary of taking Mick or Rosco... They're both animals behind the wheel :)


Cheers


Pete

[kock81]

hey marty
Done a little here and there in both planning and semi displacement but not much. know i few guys who have had them most their life.
The warp speed thing is a joke i have with them, not aimed at you at all. Was offshore on thurs with wind swell on rear qtr for trip home and was rolling around as well. just had to slow down, as after sun down it become hard to read the ocean as the moon was above and just behind us. A 9mtr cat was also telling the same story of a tough trip home last thursday, so steady as she goes when its on the rear qtr. One thing with the semi hulls is knowning when to throttle on, and when to back off, can be a bit like a bulldozer a times. There is no substitute for experience and getting a hundred driving hrs under your belt will teach you most things to know about your girl, best of luck, your boat looks like a beast by the way.
KOCK

[Captain Seaweed]

Thanks Kock,
I look forward to getting back out there....Thanks for your insight, I find if I piece together all the bits of info it starts to make sense......hard part is the amount of beers in between make it hard to retain that information....!

Cheers
Marty

[John Buoy]

One of the best tools you can have when operating multi hulled twin engine vessels are your ears.
Irrespective of sea direction your motors will tell you by the grunt which is buried whis is cavitating
when trimmed correctly both will harm in unisun even if trims are set at different heights but most importantly
is get bow as high as possible 90% of the time. As Pete has stated get out with an experienced lad and give yaslef
at least 6mths tuitorals b4 you become confident.
Great boat enjoy..

[Captain Seaweed]

Had another day out today in glass out and worked out that my trim needs to be a lot lower than I have tried before.....thanks for your info fellas!

[WalrusLike]

Had another day out today in glass out...

Bah! It's bad enough I have to work, but now I see you've been let out to play in perfect weather with your new toy. :)

I bet you had a grin from ear to ear. Good stuff.




(Using Tapatalk on iPhone so can't easily 'thank' or 'like')

[rosco1974]

come on pete,i just sit on the best speed for the kc I have found and its not full throttle...I find the 2400kc ride best at around the 26-30knts,i normally sit on 27knts which is around the 4500 revs,am sure marty will find the best cruise speed to get his beast to perform well,will take time like it has for all us cat lovers to find this sweet spot..it wont take him long if he drives it while the rest of us are working...

[Noelm]

Only thing I can add is, dont look at the motors, trim by "feel" when the boat is running right (especialy stern quarter to the sea) you will know when it is right, the motors will be at really odd trim to each other, remember, the trim works diagonaly across/along the boat, left motor up, right bow up. dont know about this walking the cat and so on, just give it a try and see how you go.

[Noelm]

Just thought of something, next time I am out, and there is a bit of sea, I will take a photo of my motors when the boat is running right, the difference in trim is alarming (thats why you dont look)