DIY Prop Guard - Page 2

HDAV · 05 December 2017, 22:59

There were some ex fire service flood rescue engines with prop guards for sale at auction recently maybe an Ex fire service kit dealer has some.

From what the op is saying buying a 15hp motor and learning to avoid submerged hazards would be a better option.

There are yellow plastic ones available didn’t think they were £150?

ShinyShoe · 05 December 2017, 23:10

Quote:

Originally Posted by Maximus

..you'll see more than one in use with the RNLI at various places/stations around the Country...

Place or Stations?

No D Class, Y Boat or B Class used in the sea has a prop guard.

The Arancia Boats used by the beach teams (i.e. life guards do). They launch with the engine running, into sea with people in it with no kill cord. I hope Lee1 doesn't

The Arancia is also used by flood rescue teams and a prop guard there makes sense too. Don't think in situations where a D is helping at a flood they add a prop guard.

Poly · 05 December 2017, 23:33

Quote:

Originally Posted by Maximus

Before you go making sweeping statements...(as usual with very little practical experience) you may like to watch a few episodes of "Saving lives at Sea" on Good ol Aunti Beeb...

I’ve watched more that a few (but not all). Which boats have you seen with guards? FWIW I have plenty of experience driving boats without prop guards... The only time I’ve thought it might be a good idea was doing safety cover at some big swimming events where people seem to swarm around you at tick over. To be honest a kayak is a better close quarters rescue craft for that sort of thing. How many people have hit your prop guard Maxi?

Quote:

you'll see more than one in use with the RNLI at various places/stations around the Country...unless ofcourse they have JUST removed the ones shown and ALL other stations never have or plan to use them in the future...

oddly despite your claims, only the beach life guard boats I mentioned in my previous posts state they have guards in the rnli’s own spec:

https://rnli.org/what-we-do/lifeboat...lifeboat-fleet

Quote:

..,Maybe if you thought a little more before you post?

Pretty much every post I make is carefully considered. Many get deleted before I hit send. You should try it sometime.

p.. · 13 September 2018, 19:07

We've been using some made years ago by Prop Mate, but they've gone out of business. To outfit our new E-Tec 40, I used one of their brackets, and just formed the ring from 1/4" thick UHMW PE. I had to modify the steering trim tab a bit to allow the rear two prop guard mounting bolts to fit.

We operate inside the surf line, near swimmers and submerged rocks, and accept the hit to the top speed.

Boat is a new FC470.

boristhebold · 13 September 2018, 20:44

Lee1 either your just trying to have a laugh or if not you should really think carefully at the mods you keep coming up with. There are reasons people dont just build cars or planes or boats or lots of other things without any engineering standards and reasons there are alot of regulations around things ... the main reasons are to keep people safe.

You make a home made prop guard and something happens and someone near you in a boat suddenly gets a chunk of metal flying at them at speed ... think about it ?

You seem like an accident waiting to happen, you even seem pleased with the fact your boat is overpowered ... do you have any boat insurance ? if you do im sure its invallid allready.

Just think about some of the things your thinking of doing .... if its not you that gets hurt it maybe someone else ... it aint worth it ..

Xk59D · 13 September 2018, 21:32

I don't think Lee is about anymore so you may not get a reply, last online 8th July. He is probably busy fixing all the engines his customers have with cheap parts or building a cruise liner out of plastic pipe and old shoes or something

Highland Haggis · 14 September 2018, 22:38

Xk59D are you booking first class for his cruise liner [emoji23][emoji23][emoji23][emoji23]

jeffstevens763@g · 15 September 2018, 18:05

Quote:

Originally Posted by p..

We've been using some made years ago by Prop Mate, but they've gone out of business. To outfit our new E-Tec 40, I used one of their brackets, and just formed the ring from 1/4" thick UHMW PE. I had to modify the steering trim tab a bit to allow the rear two prop guard mounting bolts to fit.

We operate inside the surf line, near swimmers and submerged rocks, and accept the hit to the top speed.

Boat is a new FC470.

That's great job done on the guard more impressed with the boat though love it

p.. · 16 September 2018, 04:56

Quote:

Originally Posted by jeffstevens763@g

That's great job done on the guard more impressed with the boat though love it

Thank you.

We still have an FC470 running that was first put into service in 1987. Current engine on that one is a 2002 Mercury three cylinder 750cc four stroke carbureted 40hp. It takes a lot of maintenance to keep that engine up and running, and the driver has to manage the throttle just so or the engine expresses its displeasure. But a good driver can do some pretty impressive work with it. We're hoping the new boat has a good long life too, though 30 years is asking a lot given how we use them. The fuel injection on the new E-tec will hopefully make it easier to drive than the old Merc. A lot of our new drivers have never used anything with a carburetor and accelerator pumps before, so it can be tricky to train people. Occasionally someone will inadvertently flood the old Merc by playing with the throttle while the engine isn't running.

I like the 4.7 meter boats more than the 4.2 meter boats I've tried, both FC and Futura. We also have an FC420, and have had a couple of 4.2 meter PVC Futuras. The little boats are a bit too bouncy for my taste, especially in the conditions we see, although they sure are a lot easier for a couple guys to pull off the trailer and launch from the beach than the bigger boats.

The 4.7 meter boats are a little more stable, feel less likely to get upside down, and carry an extra person and some more gear more capably.

It's not terrible work.

Roflhat · 16 September 2018, 20:16

Is your job to drive those boats?

p.. · 17 September 2018, 02:09

Quote:

Originally Posted by Roflhat

Is your job to drive those boats?

Partly, yes. I am a lifeguard.

Tim M · 17 September 2018, 06:58

Fitted a prop guard to a 4m Avon Searider once. Boat lost about 30% of its top speed and fuel consumption went through the roof. I wouldn't recommend one. Drive the boat so it's not an issue.

Roflhat · 17 September 2018, 08:17

Quote:

Originally Posted by p..

Partly, yes. I am a lifeguard.

Where do I sign up?

p.. · 05 October 2018, 14:47

Had a chance to take the boat out for a few test runs. The UHMW PE was too flexible. Tried a few modifications. Currently have the guard reprofiled, and reinforced with an aluminum ring, riveted together. Went out for a couple runs like that and it works well. Will likely at some point try to come up with something sleeker, but GPS says there's only 0.2mph top speed difference between the original and most recent prop guard designs. Wanted to avoid something so stiff that an impact would just break the anti ventilation ears off the lower unit. Have seen that happen with a stainless guard.

FWIW, currently running a Solas 13.25" x 13 pitch prop, which should work out fine when fully loaded. May try a 13" x 15 pitch prop to use when lightly loaded.

Roflhat · 05 October 2018, 15:07

Looks like you are running the engine extremely low down from that photo?

p.. · 05 October 2018, 15:12

As low as it will go. We run them inside the surf line, and the main thing to avoid (aside from hitting people in the water, or submerged rocks) is ventilation when running in frothy water. If we run the engines up at all, they ventilate easily, which is no fun at all when you're trying to get out of the way of a breaking wave.

Roflhat · 05 October 2018, 15:27

Should be able to run a lot higher than that without ventilating, I guess performance isn't too important for you but the boat will be a lot more drivable with a good prop and the engine higher

p.. · 05 October 2018, 15:33

What do you recommend for a prop? This is our first Etec 40.

The FC470 we've been running was built in 1987, and we've had a couple engines on it, currently a 2000 Mercury 40, 750cc three cylinder four stroke. We've got a lot of practice with that setup.

We were doing some training with another agency that was running a 4.2 meter Zodiac with an Etec 30, and they were having so much ventilation even with the engine mounted all the way down, we ended up pulling the engine half way through the day, cutting 2" off the top of the transom, and putting it back together. Boat ran a lot better in the conditions where it matters most for us.

Roflhat · 05 October 2018, 15:43

I don't know much about those etecs, at a guess I'd say your gear ratio is well above 2:1 if it has a 13" diameter prop as standard. Stainless props have far less flex so offer better grip on acceleration and rough conditions which is what you want. Something like a semi cleaver design is good for surf, not sure if a yamaha prop will fit, if not the Ballistic props are pretty grippy too

Roflhat · 05 October 2018, 15:46

Looks like it has a 2.67 ratio gearbox, the lowest pitch Ballistic prop that will fit is 15" pitch which should work alright, it's 12 3/8" diameter
https://www.propellerdepot.com/93331...-xhs-propeller