SF Bay Area mechanic

[Hydraulicjump]

Hey northern California TugNuts, I had my 250 hour service done today by Chuck's Marine. Chuck absolutely knows the Ranger boats and is a great resource. I was very impressed. I decided to pay someone else to do it, rather than tackle it myself, but Chuck let me watch and ask lots of stupid questions.

After the most epic TugNut string I have read since I have been haunting this site for a couple of years,

viewtopic.php?f=2&t=3732&hilit=impeller

involving Barry's Odyssey, including slaying the mighty impeller in his R-25, I decided life was too short and I should learn from (pay) a master. With Mike Rizzo's direction, I pulled things apart prior to Chuck's arrival, and he easily replaced the impeller in less than an hour. And wouldn't you know, after 250 hours, the impeller was in pretty bad shape. One torn vane, one cracked one, and all the vanes scored as if I had sucked up some sand.

Did y'all know there are shoaling problems in the Swinomish Channel southwest of La Conner, WA? Just sayin'. Look it up on Active Captain.

That's what this site is for: to share beta.

Jeff

 

[baz]

Were the cracked/split/torn impeller vanes adjacent ?
Did the compromised vanes total 3 or 4 with them being adjacent ?
Where were the scoring marks ?
Any chance you could share a photo of the old impeller ?

About the shoaling problems in the Swinomish Channel southwest of La Conner, WA... Yes, this is a known problem and I believe the Corp did dredge recently. The shallow portions are as you enter the long stretch heading east and north of Goat Island. For our Tugs, so long as you're not there at low tide it's AOK... just go slowly and stay midway between the buoys. I always try to run that channel close to high tide.

When approaching the channel and Goat Island from the south with poor visibility the series of red buoys are sometimes very difficult to see/find. Use the chart plotter to give you a sense where they're at and stay west of them keeping them to your starboard side, and don't cut off the last one to enter the channel. Enter the channel with the red and green buoys providing the entrance path.

 

[walldog]

Barry,

You can be in trouble just staying between the red and green marker buoys. There is a set of range markers at the West end of the channel. It is essential that you keep these lined up going and coming. That is where the dredging was done. There has been some shoaling since the dredging so keeping the range markers lined up will keep you in the channel. Also as you say be sure that you do not cut the West most red marker....as there are rocks between it and the adjacent red.

There are not as many range markers here in the PNW as there are on the Texas Gulf Coast. So we do not get the experience using them up here. They are a valuable tool though and will help you stay center channel in safe water.

Here is an excellent explanation of Range markers or Day boards:

http://www.boattest.com/Partners/Partne ... 607&p=0&s=

 

[baz]

Herb:

Yes I acknowledge that there's a range marker to be lined up as you enter the channel alongside Goat Island. I forgot to mention that and thanks for mentioning it. I've been up/down that channel quite a few times now and kind of know where to keep and line the boat up as I go through. I have a tendency to stay closer to the red markers rather than the green ones as one of my first transits through the channel I came close to grounding by being too close to the green ones. I believe I did hit a muddy/sandy bottom briefly as the engine sound gave me the warning and it was clearly laboring. I quickly pointed the boat away from the green markers over toward the red ones and lined the boat up using the Range marker. Of course, the Range marker is only useful in clear visibility, so it's beneficial to know where to navigate the channel in poor visibility as well.

When going up the channel from west to east toward La Conner how do you personally keep a line of sight on the Range markers as they are behind you ? Does 1st mate give you guidance ?

Another technique I've used when a large tug or gin palace is in front of me is to kind of follow it... :roll:

I've found the shallowest portion of the channel to be about 1/3 of the way from the west entrance to the abrupt left turn at its end. At this 1/3 position it can get down to just 2 feet under our boat... and 1st Mate will be tense while keeping her beady eye on the depth readings.

Thanks for the Reference on Range Markers.

 

[walldog]

Willie does watch the range markers when we are going away from them. Just easier for us. I do not let her see the depth readout. If it were foggy, it probably would not be windy and I would be outside not going through the slough. I do avoid it whenever possible. I am used to narrow channels, but the bottom changes too much in that one for me.

 

[Hydraulicjump]

Gents

When Barbara and I passed through that mess of shoals last summer we had two problems. First, it was terrible weather (rain, wind, nasty...typical of PNW before July 4th) and second, we naively imagined we could get through on a low tide, believing the charts and our 28" draft. We religiously followed the range markers (we were headed west) and found ourselves plowing a groove through mobile sand shoals and sand waves that showed up beautifully on the sonar at negative depths. Indeed, with a death grip on the helm I appreciate it, sort of, when Barbara calls out negative depths. We learned a lesson: time and tide wait for no man, so wait for the tide, man. I had to have sucked up a bunch of grit on those multiple soft groundings. A rookie mistake.

Barry, two adjacent vanes were severely cracked and torn, two additional ones had hairline cracks. All of them were scored on the outside, roughly in the center, as if a pebble had lodged in the impeller housing. Really glad I replaced it before this summer's big adventure to Johnstone Strait.

I have to PM Bruce about inserting photos. Every attempt has failed so far.

Jeff

 

[walldog]

Thanks for your post Jeff, I thought it may just be me. That channel shoals and changes too much for me....if I can avoid it, I will. Or at least wait, as you say, for a higher tide.

Lots of cross current passes through that straight stretch that has the range markers. With the current running at angles to the channel, it is bringing sand and mud across it. Not good for keeping it clear. At least if you follow the range markers, you should not hit any rocks....otherwise you may.

 

[baz]

Herb:
Talking rocks…. I believe Anne (Cascadia) hit rocks last year going through that straight stretch heading west… bent up the prop and had some minor hull damage. She told me she had to limp down Skagit Bay and over to Oak Harbor for repairs after that encounter.

Yep -- to be safe, navigate that channel as close to high tide as possible… I certainly do.

Jeff:
I'm sure Bruce can help you post photos. If you cannot raise him then PM me and I'll walk you through it. As a last ditch you should be able to post some photos to your forum account's Photo Album.

Hmmmm…. Two adjacent vanes were found torn/cracked… this aspect of adjacent vanes failing is leading me to a specific reason for impeller failures. Now answer me this… did you put your boat on the hard for any length of time in last year or two ?

 

[Bruce Moore]

There are two ways to embed images in your posts.

If the picture you want to include is in one of your gallery folders (on Tugnuts), click on the g2Img button. That will open another window which will allow you to browse your galleries and select a picture.

If the picture isn't in your gallery, perhaps something you've seen elsewhere on the web, or in another personal web collection (i.e. flickr, picassa, etc.) then you click the Img button.

This will create the following string in your posting window - then you copy and paste the URL (http://whatever...jpg) of the desired image in the middle, between the ][ brackets. The trick here is to determine the direct URL of the image. Various image hosting sites show it in different ways. Sometimes it's right up in the address bar. Other times it's listed under "Share This Image", etc.

You can determine if you have the correct URL by hitting the Preview button. If it displays, you're good to go. If it's not correct, the form will give you some kind of clue so you can go back and dig around. You'll only have to figure it out once for each host.

Cheers,

Bruce

 

[Hydraulicjump]

Thanks Bruce. I will follow your recipe. Much appreciated. When I tried to link to my Tugnut gallery I got a message that the sizing was wrong. I can try again.

And Barry, the boat lives on a trailer, so it drains out after each use. I am anticipating your concern about it dry-starting and getting prematurely worn out or warped. Of course, the way to answer this is to take it apart after a long spell on the hard and see if it is dry. When Lee Shobe had the boat (its first year) he stored it on the hard over the winter. Given that the process of inspection is such a pain in the arse, I think I will just stick with annual inspection and/or replacements. With my help the mechanic can do it in less than an hour, which makes it worth the cost.

When I took it to the mechanic this week it had been on the trailer for only two days. There was plenty of water in the impeller housing when he opened it up.

Not sure if that helps.

Jeff

 

[baz]

Jeff: Any embedded photos must not exceed 700x700 pixels -- a tugnuts.com limitation. So make sure about that before creating them. I usually stick with no more than 640x640 when I export them from my photo application on my computer. I upload them to my Dropbox web site. I use Dropbox for all my Tugnuts photos. Dropbox is free for a limited amount of space at around 2GB. If you want to employ Dropbox let me know via a PM.

So you bought Lee's green hull R-27…. nice. He used to have that docked opposite our R-25 at Port of Edmonds. If only I had known he wanted to sell it… but suspect he traded it for his R-31… 😉 drat… 🙁

Yes, leaving boat on trailer or out of water for lengths of time along with low winter temperatures seems to be a common thread for impellers that fail with 2 or 3 adjacent vanes torn/cracked/split. I've now got evidence for this from around 6 Tug owners. My speculation is that having the impeller dried out and with 2, 3 or 4 vanes severely bent over at around 90º where the housing radius is minimum creates a 'material set' (my term for an object forced into an unnatural position) for the 2, 3 or 4 vanes. If material left in this state for too long the internal stresses in the material will compromise its strength. In the case for the impeller vanes it would mean that the point where the vane is left bent at 90º (and it's the thinnest portion of the vane near its root) causes it to weaken and will easily promote splitting/cracking when eventually it's rotated. If the vane ends also stick just a tad to the housing that's also added to the issue when the impeller eventually rotates.

Given that your R-27 is far easier for having the impeller replaced than for an R-25 and that it can be done by a qualified mechanic in 1 hour it makes sense to have the impeller inspected/replaced each year. Assuming labor hourly rate of $100 and travel time to boat charge of $90 and parts cost of $40, this means out of pocket expense would be $230 + taxes… so let's say $250. For an R-25 I suspect this cost to be at least $100 more due to the difficulty of access to the impeller assembly etc that adds to the time for completing the impeller replacement.

In your case Jeff, it would seem you did pick up some 'crud' coming out of the La Conner channel and into Skagit Bay that lead to the scoring. Did your mechanic check the inner impeller housing surface for severe grooves etc. ? On the other hand I would expect small stones, gravel etc would pass through the impeller housing and be pushed out through the heat exchanger and eventually out through the wet exhaust.

The general consensus on the forum for our Tugs is to check the impeller each year (before boating season for some) and replace regardless. This IMO is good advice and a sound investment especially if the Tug has been kept on the hard over winter time.

For me personally, based on my boat's use, I will inspect/replace impeller at each 250 hrs of engine use or 4 years whichever comes first. So, if I employ a mechanic for this task I will need to add around $100 additionally to my boat's piggy bank each year.