Seagull racing boat

In the 1930s the Sea Sled was not considered a planing hull. It won every competition until they banned it. That is the original tunnel hull. If the rules don't define planing, then nothing makes sense. Very slim hulls can go at very high speeds without lifting, they actually sink. Planing speed is very controversial. There is no consensus. I think that you should either ask for clarification from the rules commitee or go fast and then challenge the rule. I would gladly organize a race in Totnes (Dart River)_

 

The River Dart Seagull race.

That sounds great is there any speed restriction on the Dart ?

How long could the race be ?

Heineken sponsor the Burmudan round the island Seagull race, perhaps they would sponsor a British one.

H-A

 

There is a 6Kt speed limit, but could be waived for a race. The rowing sculls routinely do 10Kt and more.

 

this is it ...

 

Did a little bit of testing on the Thames today.

Managed 10.6 MPH

Does this picture look like a planing boat ?

Or do we just say that as this hull is moving much faster than its displacement hull speed it must be planing?

Does the spray and wave shape determine the state of the hull, to me it looks like it is not yet up on the plane.

Sorry if this is a little in-precise but I have no experience with planing hull.

As for the quality of the photo, my wife had trouble keeping up with the speed (not).

H-A

 

The boat looks GREAT !!! Water appears to be breaking free at the transom. I like it. looks quick
a trick us sailors use is to wet sand the bottom of the hull. Very fine wet sandpaper on the morning of race day. The difference in performance is dramatic...particularly if you have any waves causing deceleration, acceleration. With a perfectly prepped bottom you will out accelerate the competition after each wave, leaving them cursing, fist pounding and sucking seagull exhaust fumes, as you hightail it down the course to victory. .
Hey ! in the rules..... is race course skulduggery prohibited ? You know stuff like.... a line of strategically positioned girls ,flashing there wobblies, distracting the competition just before the starting gun fires off ? Could be another secret weapon up your sleeve.

 

No thats not planing but you still seem determined to keep the weight distrbuted to hold the boat as much in contact with the water as possible ....move the weight back or did you try that . ....is the motor at max permitted rpm ..ie prop and motor and boat matched.

I would define planing as a state where the water leaves contact with the hull parallel to the hull bottom and does not therefore climb the sides of the hull ..... never see it below 15 kts. this applies to the sides and transom.

 

Looks like I might stay within the rules then, and still be able to do about 5mph more than the other boats in its class.

Engine is not screaming, but it may still be running a little rich.

Will look to see if I have a smaller Amal jet, also I will drop the jet needle one notch.

I have a stack of other props to try, at the moment I am running 7 1/2 X 7.

I do have a 7 1/2 X 6 1/2 or 7 1/4 X 7 1/4, which might get the revs up a bit.

H-A

 

you must must must use a rev counter ....waste of time without ....too late for me to send you one from australia but you must put just enough load on it to hold it to max rpm ...was that 3600 if memory serves ? This is the one its called a GY 14 in the trade ( sold thousands in australia )

 

The Kiwi racers say that 3800 - 4000 rpm is the engine speed that you need.

That small tacho looks good. I know that some people use the Tiny Tach, but I have not found a reasonably priced one in the UK.

Are there any other ones that people recommend ?

I think in this race, I would not need to have the engine screaming. It might draw too much attention.

H-A

 

Planing can be whatever. The rules, by definition, regulate what planing is. You can get as many opinions as you want, but they will be all worthless. Racing rules regulate the race. Why don't you get a definition from the race rules?

 

dont ask any questions H-A until there is a problem ..would be best to have the engine on full song then you can throttle up if you are not in no 1 spot...

 

I will worry more about the rules after the race.

The most important rule is No. 3 The Commodores decision is both right and final.
It can be argued out in the pub afterwards.

It is a very easy going race, all the organisers try to avoid is injury.

All I want to do is develop more of an understanding of how to make this little boat go quicker.

I will do a bit more tweaking and may get it up to the 12mph mark.

A couple of people have said roughen up the hull, is this to get some form of laminar flow?

Only problem with testing is the weather and suitable venue. You get some very odd looks on the Thames when you are doing 10.5 mph. The rowers don't like it.


Got any dates for the Totnes Seagull Race yet?

H-A

 

if the bottom of the hull is a real glass finish as in two pack then they take the shine off with scothbrite.......the hull does not slide over the water ...water sticks to the hull and shears off just below the hull ...so the water lubricates the movement .....

 

If you want to go faster, get up on a plane. Otherwise, all boats have a maximum speed determined by their waterline length. The only way to have a faster boat is to have the longest.