Milfoil & jet pumps...

[anmut]

We took a trip to Madison, WI this past weekend to boat on the chain of lakes. The lakes are really pretty, big and deep for water sports. On the two larger ones, you can see the state capital building from water, which leads to some really nice pictures.

However, our trip was interrupted by milfoil (not to be confused with Milf Oil, as my cousin called it - which would've been a lot more fun). If you've ever had to deal with this invasive species with a jet boat, you'll know the pain I'm about to describe.

First time we tried to get dock at a restaurant from the water. I saw the patches of milfoil on my way in and tried to vary the throttle speeds keep the pumps in "blender mode" - this has been successful in the past when dealing with other weed areas. What I didn't realize is how milfoil clumps up. Within a minute I had an overheat warning on the port engine. We got to the dock, and I spent the next 20 minutes trying to clean out the pumps through the cleanout port. My wife then noticed the "no dogs allowed" sign so after all of that work, we weren't eating there anyway. So off we went on one motor, trying to navigate out to cleaner water. I was unable to clean out the pumps through the access manholes - so eventually I donned my daughters pink swim goggles and jumped in the water. Pulling the weeds out from under the boat was MUCH easier - most of it was jammed up against the grate and didn't need a lot of strength to pull out. A few restarts to check the pissers and continue to clean the pumps out and we were on our way. Total down time was probably 45min, however, I could've been done quicker had I jumped into the water to being with and not even bothered with the clean out ports.

On the next day, the same thing happened as we cruised back to the boat landing to pick up some extra riders. However this time I didn't get an overheat warning, I could just tell that the pumps were clogged by the way they sucking air at high RPM. Taking the previous day's lesson into account, I quickly jumped in the water and, a few held breaths later, I was able to clean everything out and get on our way again.

If I can share some lessons learned:

1. If you see milfoil, avoid it at all costs. You won't chop your way through it. If you have to go through it, get a running start, and shut your motors off as you glide through, restarting when only when you need control of the boat again.
2. If you get milfoil jammed up, jump in the water and dislodge from the intake grates - you're asking for a long day and rapped knuckles if you try to do it by hand through the cleanout ports.
3. If you are on a lake like we were and they take part in milfoil "chopping," avoid the sides of the lake where the wind will push those floating masses.
4. If you're wake foiling on a lake with milfoil, and find yourself suddenly diving in the water for no reason, congrats - you just hit a milfoil patch.

On a funny note, on our second day putting in at the boat launch I had a nice young lady come over to us as we were prepping to put in and ask me if she could ask some questions about invasive species... I was like "I think you're a little late to the ball game here..." which got a pretty good chuckle from her.

 

[tdonoughue]

Yuck.

I often wonder if a long, curved rake could be fashioned for those times when you can't do the 'reverse move' (because you need to be able to get going in reverse in order to do that one).

 

[zipper]

Very experienced with millfoil wraping around the drive shafts. But I never had to jump in the water.

 

[Madcityami]

I’m on Mendota and probably pulled the clean outs 5 times this weekend. I’ve gotten good at avoiding the milfoil islands, but somehow the intakes can still get completely clogged. On Sunday they were so jam packed, I could not get any propulsion for the backup move…or cooling water pressure. Jet ski guys on the west side of lake were puffing some pretty good smoke too. Almost regretted the jet boat this weekend.

 

[SCP1]

Maybe we need a Milfoil trophy. If I recall I warned you about the weeds. Went to Monona once over off of John Nolen and never returned. Just another addition too my list of why I avoid the Madison lakes!

 

[anmut]

Maybe we need a Milfoil trophy. If I recall I warned you about the weeds. Went to Monona once over off of John Nolen and never returned. Just another addition too my list of why I avoid the Madison lakes!

Monona wasn't bad at all, it was actually clear and clean - but they must have been doing some sort of "mowing" of the milfoil on the southern lake, because there were big patches of it floating in the middle of the lake.

 

[Richard Bares]

I was also out on the Madison lakes this weekend. We normally launch on Waubesa and take the channel up to Monona. Waubesa is particularly bad in part due to lake levels being so low. Also, they are doing weed mitigation right by the launch that we use. There was a ton of floating weed patches on both Waubesa and Monona but surprisingly where we hang out it was the clearest I've see it yet.
We didn't necessarily have any clogs but I did pull a fair amount off the intake grates after getting back on the trailer.

 

[Julian]

When we lived in the midwest, I got very used to dealing with Milfoil. When I knew we were running into thicker areas I'd immediately switch to one engine at a time. My approach would differ depending on the distances I needed to travel through it. But my first approach was to always use the reverse maneuver first to clear the one engine I used. This was usually pretty successful. If I had to traverse a LONG channel between lakes (Tomahawk) I'd be ready to drop an anchor in the event I clogged both and had to go manual.

 

[anmut]

I was also out on the Madison lakes this weekend. We normally launch on Waubesa and take the channel up to Monona. Waubesa is particularly bad in part due to lake levels being so low. Also, they are doing weed mitigation right by the launch that we use. There was a ton of floating weed patches on both Waubesa and Monona but surprisingly where we hang out it was the clearest I've see it yet.
We didn't necessarily have any clogs but I did pull a fair amount off the intake grates after getting back on the trailer.

Nice - I only saw one other Yamaha out there (newer 24' AR) - were you at the sandbar on Gilligan's Island?

Waubesa was the absolute worst I've ever dealt with when it comes to milfoil. Monona was very clear for the few hours we were out there. We never went to Mendota (we were warned in advance).

 

[anmut]

When we lived in the midwest, I got very used to dealing with Milfoil. When I knew we were running into thicker areas I'd immediately switch to one engine at a time. My approach would differ depending on the distances I needed to travel through it. But my first approach was to always use the reverse maneuver first to clear the one engine I used. This was usually pretty successful. If I had to traverse a LONG channel between lakes (Tomahawk) I'd be ready to drop an anchor in the event I clogged both and had to go manual.

Now that's an interesting strategy that I've never considered. So just alternate between the two engines, use the RM to unclog. Thanks!

 

[Richard Bares]

We've never hung out at Gilligan's island, always too crowded for my taste. We either float out in front of Monona Terrace in the deep water or head over to Holy Bay at the north east end of the lake where it's waste deep or so.

 

[anmut]

We've never hung out at Gilligan's island, always too crowded for my taste. We either float out in front of Monona Terrace in the deep water or head over to Holy Bay at the north east end of the lake where it's waste deep or so.

That was our first time at that sandbar - we went there Friday and it was very family friendly. Saturday during the day wasn't bad, but you could tell the crowd was younger. Later that evening my wife wanted to stop back after dinner and let the kids play again - she ended up not being impressed with all the drunk chicks. I though I was suddenly at a stripper party or something...

Edit: I saw a Yamaha on a Madison Boaters facebook page for the party at Holy Bay - was that y'all?

 

[Richard Bares]

It definitely gets more rowdy the later it is. We were also out on Sunday. There weren't a whole lot of people out when we went by about 11:30. Later in the day closer to 5 it was pretty busy. We have been too busy this summer to go out on Saturday's.

 

[OrangeTJ]

Milfoil is a menace. My encounters with it in a jet boat have been in the Tahoe Keys, where you have to navigate a fairly large shallow area that is infested with milfoil to get from your house's dock to the amazingly clean & clear Lake Tahoe. When we had our SX210, it would invariably end up with clogged pumps by the time we got to the channel to the lake and we'd have to stop and clear it out before proceeding to clean water. Not fun, especially when there are lots of other boats coming and going.

This is why, when people ask for opinions on whether they should get a jet boat, I consistently respond that if they boat frequently in waters with surface or subsurface vegetation they may not love the jet experience.

 

[Ribs77]

I've got a lot of milfoil growing around my wet slip in the marina. I've used a pool skimmer to scoop away the floating parts near my boat before entering/exiting, but I can see stalks growing up from below that I can't necessarily reach or pluck out.

I've seemingly never had any clogged intake, and the last time I pulled the cleanout, the shaft looked clean. So it seems as though I'm probably not sucking up vast quantities of the stuff going at no-wake speeds in and out of the marina, right?

My other question is...if I did suck up a bunch of milfoil, could it damage the impeller? I've been getting cavitation at low RPMs on hard acceleration - maybe it's from the conditions being a bit choppy - but I want to make sure I don't have a problem brewing. I don't seem to have an issue with getting the revs up to where they should be, FWIW.

And fortunately it's a huge and deep lake, so once I get out of the marina, there's no milfoil around at all.

 

[anmut]

I've got a lot of milfoil growing around my wet slip in the marina. I've used a pool skimmer to scoop away the floating parts near my boat before entering/exiting, but I can see stalks growing up from below that I can't necessarily reach or pluck out.

I've seemingly never had any clogged intake, and the last time I pulled the cleanout, the shaft looked clean. So it seems as though I'm probably not sucking up vast quantities of the stuff going at no-wake speeds in and out of the marina, right?

My other question is...if I did suck up a bunch of milfoil, could it damage the impeller? I've been getting cavitation at low RPMs on hard acceleration - maybe it's from the conditions being a bit choppy - but I want to make sure I don't have a problem brewing. I don't seem to have an issue with getting the revs up to where they should be, FWIW.

And fortunately it's a huge and deep lake, so once I get out of the marina, there's no milfoil around at all.

Speaking from experience (as posted earlier in this thread) - small patches of milfoil, growing in clumps, won't clog or damage anything. You can bump your throttle up/down while maneuvering slowly through this to help the pumps "blend it up."

What you want to watch out for is floating patches of it that was harvested - that is, a lot of lakes now are bringing in machinery to try to cut and get rid of it. I've sucked up some of these larger patches and the BEST way to get it out is to put a life jacket on and go under the boat and pull it out. Trying to get milfoil out of the cleanout ports is difficult at best.