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| Thread ID: 120892 | 2011-10-01 08:27:00 | Any boat experts here? | prefect (6291) | PC World Chat |
| Post ID | Timestamp | Content | User | ||
| 1234856 | 2011-10-01 08:27:00 | I would like to modify my seagull racing boat for next year. My boat was a kiwicat like a hobie cat with a piece of 2" square section aluminium on the back with 2 seagulls. It goes alright got second in its class on first attempt last year but the backwash from the leg of the left side seagull kept going down the carb intake any passing boat or rough water stopped the engine. Also when the boat was at full speed the nose came up slightly and I had to to stand forward to get the nose down to get a couple more kph. My plan is to turn the frame around and put the motors in the front. My questions Will the nose rise with motors on the front? What will it do the balance, do I need to move the seat and fuel tank aft? Can I do a c of g balance by say balancing the hull on a bar half way down the hulls with engines on front and myself and fuel to balance it. Is the c o g on boats like an aircraft? Thanks for any help |
prefect (6291) | ||
| 1234857 | 2011-10-01 09:58:00 | Try changing the Seagulls for Albatross and feed them plenty of fisn'n'chips ... put one foward, one aft ... It'll help with the balance problem ... :rolleyes: | SP8's (9836) | ||
| 1234858 | 2011-10-01 19:39:00 | You normally trim the engines up slightly to drop the nose, but on a manual lift engine you probably cannot do that, Moving body weight forward is the next best thing | gary67 (56) | ||
| 1234859 | 2011-10-01 19:42:00 | Sounds interesting prefect, got any photos? | Gobe1 (6290) | ||
| 1234860 | 2011-10-01 19:51:00 | picasaweb.google.com picasaweb.google.com |
prefect (6291) | ||
| 1234861 | 2011-10-01 19:56:00 | Nice one, power to weight looks good. | Gobe1 (6290) | ||
| 1234862 | 2011-10-01 20:41:00 | Prefect, I'm not sure why you would want to move the engines to the front. The result is still going to give you a downward moment but at the bow rather than the stern, and increased the further it gets from the COG. I think you'll have to move the weight much further aft to compensate. But my surmise is based on aeronautical assumptions so is probably way out. Let's know what the outcome is. Don't sink the boat in the process :) | WalOne (4202) | ||
| 1234863 | 2011-10-02 02:40:00 | Why not just shift the fuel tank(s) closer to the front? Petroil weighs about .710 a kg. 20 litre would weigh about 14kg (+ the weight of the tank), so shifting the weight forward would make quite a difference on keeping the nose down. For eg just like balancing a caravan when towing. 20 kg taken from the back of the caravan & put in the front = 40 kg weight on the tow ball. Certainly won't take much on a boat. | BobM (1138) | ||
| 1234864 | 2011-10-02 05:10:00 | Still got the problem with wash from the leg going down the carb, you wouldnt get this with a transom. | prefect (6291) | ||
| 1234865 | 2011-10-02 06:44:00 | Are you allowed to put a planing fin on the outboard, like permatrim etc? | Ofthesea (14129) | ||
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