Any mods to prevent props eating rope?

[island808]

Crabbimg is a big passtime of a lot of the %}*]*#% out here. They frequently use black bouys not much bigger than a softbal; all but invisible on a cloudy windy day and not visible in low light, or when the sun is in your eyes. Ive only sucked up a couple, but they make going out much less fun. Always worried if ive damaged my outboard. Constantly having the entire family scanning the water if were anywhere close to a port. Tiresome.

Today i returned to the marina to find a string of bouys right across the entrance. At least they were beachball sized floats. That and im frequently in very shallow water, my anchor has dragged up old lines... I imagine my engine has come close.

Anyway. Looked around and a lot of the gadgets intended to keep ropes out of the prop seem to have quite a few detractors... Are they snake oil?

[mastreb]

If you're moving forward, the hull and lower unit of the outboard actually do a near perfect job of keeping line out of the prop. You're unlikely to catch a line even if you power directly over it.

Reversing, however, is an entirely different matter. You're highly likely to suck up a line if you back up.

Finally, in a Mac we have the great benefit of being able to raise the prop completely out of the water, take our leatherman to it, and cut away any rope or line which might be fouled in the prop.

My tactic is to not worry about it.

Matt

[yukonbob]

If they're using lead core then it can be a little harder to cut, but at about a hundred bucks for trap, line and marker, you're winning the war.

[Catigale]

Im guessing you are sailing the Chesapeake area? Ive sailed that a bit and been amazed at how the crab pots are sunk on the marked channel line - and sometimes over. Ive caught a few there, but managed to get clear without damage to boat or pot.

The transom does suck them in, unlike the

[Russ]

I've experienced what you speak of and empathize. I've gotten so frustrated I had fantasies of going through with a sharp device and cutting them all which would teach the guy for putting pots in busy channel areas.
Mastreb is right, we are lucky, we can easily tilt and cut the line if it gets caught. An inboard boat requires a dive over the side (been there done that).

http://www.outboardjets.com/index.php

[mastreb]

This gets me thinking:

Is there any advantage to inboard propulsion on a boat requiring <1000hp other than that you have more control over transom design? I guess there's the fact you can also run deisel, but you can do diesel with an inboard motor and a stern-drive.

Not being able to raise the prop, the cost of thru-hull bearings, and the constant leaking issues are such a PIA I can't believe smaller boats are still designed with thru-hull props.

My brother's ranger 33 has an inboard prop with the spade rudder right behind it. The rudder works great for directing thrust when you're going forward--turns on a dime, but when you're reversing it's near impossible to intuit what the boat is actually going to do. I tried to back it to a dock in reverse over the weekend and it kept rotating in place. I eventually had to give up and come around forward.

Matt

[seahouse]

Hey Matt ---

My brother's ranger 33 has an inboard prop with the spade rudder right behind it. The rudder works great for directing thrust when you're going forward--turns on a dime, but when you're reversing it's near impossible to intuit what the boat is actually going to do. I tried to back it to a dock in reverse over the weekend and it kept rotating in place. I eventually had to give up and come around forward.

Not at all familiar with the specifics of a Ranger, but a close inspection of the tension and fittings on the steering mechanism might be in order. Moving too fast in reverse (eg. by the previous owner) can generate strong forces on this type of (horn balanced, pivot point ahead of centre) rudder, which could have loosened something (set screws, cables) or sheared something (shear pin or key).

If anything along the steering line is loose (slippage on the shaft, drum etc) the rudder will flop over to full deflection in reverse and stay there until the boat slows enough to regain control.

Of course, even though full throttle might happen to be available in reverse, it is not intended in many designs (of rudders, and other components) that any speed be gained, or allowed to build, in reverse. Full throttle, if available to the operator, and not locked out, is intended for speed arresting and manoeuvring, and not for running.

On edit: (Not meaning to imply that you were using full throttle in reverse, just using it as an example of what someone could have done to loosen the steering mechanism).

[mastreb]

Hi Seahouse,

I think you're exactly right--I was thinking the boat was acting like the rudder was fully deflected one side or to the other, and I was under nearly full power to reverse. The steering seems to me to be less direct than it should be, but without a rudder angle indicator it's not possible to tell where it's really at.

Thanks for the advice as always!

[seahouse]

Always a pleasure, sir!

Of course, as usual it's way more involved than I describe above; prop walk has an effect more pronounced when the prop shaft is angled downward; prop wash does not assist in the authority of the turn in reverse because it's no longer impinging on the side of the rudder as it does when moving forward; and the hull (~keel size) gets caught in the turbulence of the prop when reversing, which doesn't happen when moving forward.

Back on original topic, I'll also point out (it might not be obvious to some readers of the thread) that a jet boat is NOT something you want to go over a line in the water with, compared to an open prop outboard like ours.

Ropes will get sucked in past the intake grate of a jet (this happened just last week at a local club); getting to the impeller to clear it requires disassembly that cannot be done in the water (you are DEAD in the water now, unlike an outboard/drive); the prop rotation cannot be reversed to clear it if minor (jet boats instead have thrust reversers, like jet airliners), and there is a ring at the perimeter of the impeller that can easily be damaged. But – a jet impeller has sharper-edged stainless steel blades and so might chop through some smaller (shorter) obstructions that an open prop might not.

Catching a line in an outboard can damage the shaft seal to the lower gearcase, so it's a good idea to check that after an incident. Fishing line did this to me once years ago, I didn't even realize it at first – it was hidden inside the prop tube- but I mysteriously had a bit of water in the lower gearcase at the end of the season . It's one reason they don't allow fishing around marinas. At least around here.

[Catigale]

A beautiful solution for boats under 40 feet is a outboard well which put the motor under the hull, with handling advantages, but allows simple servicing of the motor from up top..including clearing fouled props.

[Highlander]

Well if u remove the prop altogether that'll usually keep it from eating line

J