Alum cat running great into the wind, downwind not

Post Options Post Options   Likes (0) Likes(0)   Quote jules75 Quote  Post ReplyReply Direct Link To This Post Topic: Alum cat running great into the wind, downwind not
    Posted: 02 Jan 2023 at 3:50pm
jules75 View Drop Down
Bronze
Bronze


Joined: 15 Nov 2015
Status: Offline
Points: 92

I have recently built a 4.5m aluminium catamaran and have spent a lot of time testing to get the optimum set up for the motor height with a number of other modifications (extending the hulls, centre sponson).
I have been testing it in all sorts of conditions in a local river which is very wide. Into the wind and waves it goes like a cut cat (no pun intended) but when going down wind it (the motor) really doesn't like it. There are no waves to speak of just surface ripple.
I'm just wondering if anyone knows why this would be?? It will be creating lift going into the wind but I don't know why I can't get the same sort of performance (it's a fishing boat predominantly but wanting to do the occasion biscuiting with the kids) either way. Not that I'm looking for performance per se but just don't want the motor to bog down like it does depending on wind direction. Any help appreciated...
Back to Top
Post Options Post Options   Likes (0) Likes(0)   Quote Fish Addict Quote  Post ReplyReply Direct Link To This Post Posted: 02 Jan 2023 at 11:13pm
Fish Addict View Drop Down
Platinum
Platinum


Joined: 05 Jul 2009
Location: Perth WA
Status: Offline
Points: 2057
Good upwind and not so good downwind is a characteristic of most cats, including those with twin motors. As a previous cat owner, (twin motors) I found they can be brilliant in some conditions and not so flash in other conditions. It was certainly a learning curve driving a cat after previously owning mono hulls. Increasing the speed often resulted in a better ride. Try trimming the motor up and opening the throttle (sensibly of course) and see what happens.    
   
Back to Top
Post Options Post Options   Likes (0) Likes(0)   Quote Bounty Hunter Quote  Post ReplyReply Direct Link To This Post Posted: 03 Jan 2023 at 8:57am
Bounty Hunter View Drop Down
Titanium
Titanium
Avatar

Joined: 14 Nov 2002
Location: Russell
Status: Offline
Points: 4351
sailors know it as 'apparent wind' 

- less pressure under the bridge-deck going down wind = less lift
No disintegrations!
Back to Top
Post Options Post Options   Likes (1) Likes(1)   Quote OneWayTraffic Quote  Post ReplyReply Direct Link To This Post Posted: 05 Jan 2023 at 7:13am
OneWayTraffic View Drop Down
Platinum
Platinum
Avatar

Joined: 19 Jan 2013
Location: Amberley
Status: Offline
Points: 2787
Got any more photos of the boat and build process? Some of us like looking at projects.
Back to Top
Post Options Post Options   Likes (0) Likes(0)   Quote Shambles Quote  Post ReplyReply Direct Link To This Post Posted: 07 Jan 2023 at 4:33pm
Shambles View Drop Down
Bronze
Bronze


Joined: 07 Jan 2023
Status: Offline
Points: 7
Hey mate,
I don’t have any answers to your question but have a 4.5m cat myself. If you’re interested in checking out my setup, or just discussing small power cats quirks, let me know. I have a few questions of my own. I think it’s a great platform though.
Back to Top
Post Options Post Options   Likes (0) Likes(0)   Quote jules75 Quote  Post ReplyReply Direct Link To This Post Posted: 13 Jan 2023 at 11:07am
jules75 View Drop Down
Bronze
Bronze


Joined: 15 Nov 2015
Status: Offline
Points: 92
Here's a couple of photos of build etc
Back to Top
Post Options Post Options   Likes (0) Likes(0)   Quote jules75 Quote  Post ReplyReply Direct Link To This Post Posted: 13 Jan 2023 at 11:10am
jules75 View Drop Down
Bronze
Bronze


Joined: 15 Nov 2015
Status: Offline
Points: 92
Back to Top
Post Options Post Options   Likes (0) Likes(0)   Quote jules75 Quote  Post ReplyReply Direct Link To This Post Posted: 13 Jan 2023 at 11:12am
jules75 View Drop Down
Bronze
Bronze


Joined: 15 Nov 2015
Status: Offline
Points: 92
Back to Top
Post Options Post Options   Likes (0) Likes(0)   Quote jules75 Quote  Post ReplyReply Direct Link To This Post Posted: 13 Jan 2023 at 11:14am
jules75 View Drop Down
Bronze
Bronze


Joined: 15 Nov 2015
Status: Offline
Points: 92
Back to Top
Post Options Post Options   Likes (0) Likes(0)   Quote jules75 Quote  Post ReplyReply Direct Link To This Post Posted: 13 Jan 2023 at 11:20am
jules75 View Drop Down
Bronze
Bronze


Joined: 15 Nov 2015
Status: Offline
Points: 92
Hi Shambles. Yeah mate I'm very keen to discuss cats with you! Could you send a few photos on your other post of your minicat?
Back to Top
Post Options Post Options   Likes (1) Likes(1)   Quote jules75 Quote  Post ReplyReply Direct Link To This Post Posted: 24 Jan 2023 at 10:36am
jules75 View Drop Down
Bronze
Bronze


Joined: 15 Nov 2015
Status: Offline
Points: 92
Update: I think I've nearly cracked it! Went for a run I the river yesterday at Foxton. There was a fair breeze blowing at times up and down the length of the river so it was good to test into the wind (optimum) full throttle and very quick again with lots of wind being pushed into the tunnel creating good lift. The runs with the wind behind us initially were frustrating because there was a noticeable difference in performance. I found opening it up to full throttle made it run better with the outboard liking it more. Still about 80% of the into the wind results but I was happy enough.The lower down revs not so much. Again more wind forced down the tunnel...Also this was the first time I tried the longer anti-cavitation plate that I made. I think it made quite a difference when trimmed up. The new plate extends around 100mm longer to the rear.
While we were there my kids and I tried out their new ski biscuit which went well too!
Back to Top
Post Options Post Options   Likes (0) Likes(0)   Quote smudge Quote  Post ReplyReply Direct Link To This Post Posted: 24 Jan 2023 at 4:54pm
smudge View Drop Down
Moderator - Ninja
Moderator - Ninja
Avatar

Joined: 17 Jul 2002
Location: Te Toro
Status: Offline
Points: 31305
Good work, you must have been a bit worried initially
Best gurnard fisherman in my street
Back to Top
Forum Jump
Forum Permissions View Drop Down


This page was generated in 0.211 seconds.

Fishing Reports Visit Reports

Rotorua Area Report - 01/06/23

Ngongataha stream fishing well  In between the large weather fronts that are still regularly hitting... Read More >

Canterbury Fishing Report - 01/06/23

Lures make easy work of fishing the depths  We have a bit of a mixed... Read More >

'Top of the South' Fishing Report - 01/06/23

Opportunities few and far between – make the most of them!  The weather certainly has... Read More >

Bay of Islands Fishing Report - 01/06/23

Some good snapper still around  The last fortnight has seen more weather windows than usual,... Read More >

Fishing bite times Fishing bite times

Major Bites

Minor Bites

Major Bites

Minor Bites