Aqua Marina Aircat 335 + Tohatsu MFS9.8B
Posted: 22 Sep 2024, 10:16
Hello all 
New around here as we've just got into sibbing and bought a used 3.35 Aqua Marina Aircat. It's is perfect for us because we can pack up in the car and stow it in the shed at home as we have no facility to store a rib or trailer.
The intention is to use it for exploring Poole Harbour with my wife and two small girls (approx. 190/200kg all up).
Here she is:
On our maiden voyage we mated it with a little 5HP Tohatsu. Unfortunately though, despite being on the first hole, we had major ventilation problems. We tried to shift our weight on the boat to different positions but we couldn't seem to fix it. Clearly this resulted in us not being able to shift along at any decent pace.
After a bit of research, I found that this appears to be a common issue with these inflatable cats and a hydrofoil is usually the first recommended option to cure it so I purchased a Stingray Airo from Avon Marina in Christchurch.
However, before I fitted it to the 5HP Tohatsu, I bought a 9.8HP Tohatsu on eBay by putting in a cheeky eBay offer. After a dressing down from the wife for an unauthorised purchase 
I fitted the hydrofoil to the 9.8 and we hit the water again yesterday morning. Again, we had ventilation issues 
I feel like I'm revving the guts out of the engine and not really getting anywhere 
From reading around, I understand that have two options:
1. Cut down the transom so the outboard leg sits lower in the water - which I don't really want to do if I can help it
2. Fit a different prop
Concerning option 2, I came across this thread where the guy had a Takacat with a 9.8HP Tohatsu and he fitted a 7" pitch, cupped prop which solved all his ventilation issues (factory standard is an 8.3" pitch).
https://www.cruisersforum.com/forums/f1 ... 67930.html
I'm keen to hear some opinions so we can start enjoying our new purchase. If a replacement prop is the next step, I could probably purchase online but where would I take it to get it cupped?
Hope you can help!
New around here as we've just got into sibbing and bought a used 3.35 Aqua Marina Aircat. It's is perfect for us because we can pack up in the car and stow it in the shed at home as we have no facility to store a rib or trailer.
The intention is to use it for exploring Poole Harbour with my wife and two small girls (approx. 190/200kg all up).
Here she is:
After a bit of research, I found that this appears to be a common issue with these inflatable cats and a hydrofoil is usually the first recommended option to cure it so I purchased a Stingray Airo from Avon Marina in Christchurch.
I fitted the hydrofoil to the 9.8 and we hit the water again yesterday morning. Again, we had ventilation issues I feel like I'm revving the guts out of the engine and not really getting anywhere From reading around, I understand that have two options:
1. Cut down the transom so the outboard leg sits lower in the water - which I don't really want to do if I can help it
2. Fit a different prop
Concerning option 2, I came across this thread where the guy had a Takacat with a 9.8HP Tohatsu and he fitted a 7" pitch, cupped prop which solved all his ventilation issues (factory standard is an 8.3" pitch).
https://www.cruisersforum.com/forums/f1 ... 67930.html
I'm keen to hear some opinions so we can start enjoying our new purchase. If a replacement prop is the next step, I could probably purchase online but where would I take it to get it cupped?
Hope you can help!