Prop

[kevinemery]

Hi
I am new to this forum but not to Seagulls, I have owned a few over the years and have a reasonable knowledge of there workings as I usually buy non runners and repair them. John at SOS has been a great help.
I recently bought a 9 ft cathedral hull boat and decided to put a 102 on it that I have had for a couple of years, the engine was a non runner and the previous owner had spent some time trying to restore it and get it running which he was not able to do. A quick phone call to John at SOS and the workshop manual arrived, 2 hours later it was running.
Now I claim to have some knowledge about seagull outboards but you guys have blown me away, I found the forum by chance while looking for anti-cavitation plates and cant believe the depth of your combined knowledge and I am hoping you can help me.
My 102 has a three bladed prop, can I change it to a 4 or 5 blade and will this improve performance, the motor is mounted at the correct height.
I have made a anti-cavitation plate but have not tested it yet.
Thank you in advance for your comments.

[Horsley-Anarak]

Hi and welcome to the forum.

I use a 4 bladed prop on my 102 race engine, it goes well.

Polish it up a bit and file off the rough spots.

This is plenty of prop for my 102 on my 14 foot boat, but it goes OK.

http://www.youtube.com/watch?v=3YyWD6QMmLs

H-A

[kevinemery]

Thanks for your response.
Does the four blade have an advantage over the three blade.
Why did you pick a four blade, have you tried different types.

Kevin

[Michael]

There are so many variables it is not really possible to suggest which might be the best prop for you. By that I mean different boats, how they are loaded, different style gearboxes and ratios, number of passengers etc etc.
Best thing to do is get a handheld GPS, a bunch of props and then go testing.

[kevinemery]

Thanks
I was hoping for a short cut or at least to narrow it down to a couple of types.
Looks like I will have to start collecting props, the wife will be chuffed.
Is this going to be worth the effort or should I just polish the one I have.

[Horsley-Anarak]

Thanks
should I just polish the one I have.

Those three bladed ones are a bit industrial, I would look out for a TC four blade prop as a first try.

They are about

This is on the bay, speak to John he will have some.

H-A

[kevinemery]

Really appreciate that, have already mailed John hopefully he will have one if not at least I have somewhere to start.
Did polishing it make a difference, improve performance by much.

[Horsley-Anarak]

Did polishing it make a difference, improve performance by much.

It can only help, bit of polishing here, bit of polishing there, it all adds up.

It goes better than a standard 102. http://www.youtube.com/watch?v=7iAjAhD5D5I

H-A

[Michael]

Kevin,
Any Seagull prop will fit your engine, all will preform a little differently depending on your setup. Howeevr, my first choice would be a 102 4 blade prop.
Polishing, thinning of blades etc, should increase performance, but do not expect to feel teh difference, as it will be small. You would need a rev counter and accurate speed tests to be sure that there was a speed increase.
To have a fast Seagull, there are many things to be done to the engine, the gearbox and prop choices etc. Each improvement will yield little gain on its own, but if all or most improvements are done, the increase will be very noticeable

[kevinemery]

HA
Thanks for your help, John @ SOS has got a prop and interestingly he says "the 4 blade Hydrofan is more efficient!".

I note that you called your motor your race engine, where do you race it?
The only race I can find is the one at Lerrny which is a long way for me to go and your not allowed to break the speed limit. I understand why its organised as it is.
I have just finished building a small electric boat and am looking for my next project, I have always wanted to build a seagull race boat but do not see the point as I cant find any races. I did see that there was one at Haying Island last year but cant find any information on it.

Thanks again for your help.
Kevin

[kevinemery]

Michael
Thanks for the information.
My winter project looks like its going to be building a fast seagull.
I will start a new post in the next day or two and see what the general consensus is about engine type, gear box etc.

[Horsley-Anarak]

I note that you called your motor your race engine, where do you race it?

I try and do all the races in the UK, there are only a couple, Lerryn, Hayling. Not sure we are doing Hayling this year, I am committed to a party on the only good tide day.

Lerryn is not that far, much nearer than NZ.

We are still looking for a good fresh water venue, but they are proving hard to find, are there any near Rugby?

If you want to build a race engine P.M. Charles Large and he will phone you and talk you through it.

H-A

[kevinemery]

Prop has arrived, any tips on polishing.
When I polish gun parts I use a paste, should I invest in a wheel of some type or should I spend days rubbing?

[Horsley-Anarak]

I would just stick it on and try it.

Polishing I use stuff like this http://www.ebay.co.uk/itm/370w-Bench-Gr ... 3f1f9a7e8f

H-A

[Michael]

i agree, try it as is. Then if you want polish it and try again and see if you have any improvement in performance