VDO Sumlog replacement ?

[Refueler]

The mechanical Sumlog on my MoBo has broken cable and the impellor looks as if its been attacked by rabid dogs !! The 'blades' are missing chunks.

I can find cable ... no idea if length is ok though ... but impellor seems not easy to find. My Speed log is based on 0 - 30kts ... but all I find are 0-40kts.. Price of cable is daylight robbery of course !!

I have a new in box NASA dual Speed and Depth ... so thinking maybe to remove the VDO and replace with the NASA ... would mean cutting hole in hull where Sumlog is bolted through. Depth of course can be in hull ...
Boat at present has no depth sounder at all.
But I noticed that slings on lift out were catching the Sumlog impellor - maybe its why its damaged from actions before. Yes I can 'pull' log and put in plug ... but not something I like doing.

Another way of course would be to mount a Pitot Tube speed on the transom .....

Which ever way - seems either silly money or making holes in hull !

What would you do ?

 

[julians]

The mechanical Sumlog on my MoBo has broken cable and the impellor looks as if its been attacked by rabid dogs !! The 'blades' are missing chunks.

I can find cable ... no idea if length is ok though ... but impellor seems not easy to find. My Speed log is based on 0 - 30kts ... but all I find are 0-40kts.. Price of cable is daylight robbery of course !!

I have a new in box NASA dual Speed and Depth ... so thinking maybe to remove the VDO and replace with the NASA ... would mean cutting hole in hull where Sumlog is bolted through. Depth of course can be in hull ...
Boat at present has no depth sounder at all.
But I noticed that slings on lift out were catching the Sumlog impellor - maybe its why its damaged from actions before. Yes I can 'pull' log and put in plug ... but not something I like doing.

Another way of course would be to mount a Pitot Tube speed on the transom .....

Which ever way - seems either silly money or making holes in hull !

What would you do ?

Can you get a GPS based speedo? OK, it's only going to give speed over ground and not speed through water, but thats probably OK?

Get a garmin/simrad etc mfd with external GPS antenna, and you can have charts on there too, also can display depth from your depth sounder

 

[Refueler]

Can you get a GPS based speedo? OK, it's only going to give speed over ground and not speed through water, but thats probably OK?

Get a garmin/simrad etc mfd with external GPS antenna, and you can have charts on there too, also can display depth from your depth sounder

I already have Navionics Boating and Lakes tablet / phone display at helm - so GPS speed / plotting etc is already there.

The question comes down to depth and STW ....

 

[julians]

I already have Navionics Boating and Lakes tablet / phone display at helm - so GPS speed / plotting etc is already there.

The question comes down to depth and STW ....

I'd just use that then, I only have speed over ground on my boat, haven't felt the need for speed through water.

Keep it simple, the less holes in the hull the better

 

[DAKA]

The impeller is also known as a paddle wheel

Sumlog paddle wheel 18 knt | eBay

 

[Refueler]

The impeller is also known as a paddle wheel

Sumlog paddle wheel 18 knt | eBay

That's the later version ....

Mine is the older version :

 

[Keith-i]

So that's what they look like off the boat. I have one on my boat and have always wondered if there were any seals that could fail or if the cable tubing could split and cause a sinking event. Luckily I have a spare impellor in my collection but I have to say, yours doesn't look too bad.

 

[Refueler]

So that's what they look like off the boat. I have one on my boat and have always wondered if there were any seals that could fail or if the cable tubing could split and cause a sinking event. Luckily I have a spare impellor in my collection but I have to say, yours doesn't look too bad.

That's not mine ! That's an example I grabbed of the net.

Mine has near half of each blade bitten away ..

I thought I had a photo of it ... but cannot find it.

 

[Chris H]

Pic of my old damaged sum log, found a new one online a few years ago, think it was around £250

 

[Refueler]

Pic of my old damaged sum log, found a new one online a few years ago, think it was around £250

Yes that the later paddle wheel version ... mines the mechanical cable driven older type.

TBH - I was surprised to see it on the boat - but I suppose in 70's it was pretty well THE standard ... it was seen a lot on sailboats ..

I have decided that its coming out and Clipper Duet will be installed. The helm console where the Sumlog display is - take that out and there's large enough space for the Clipper display. This will give me depth as well.

We have plans to exit harbour .. run along beach line fishing for 'Cambola' ..... cousin of the Flounder ..... depth is going to be important ... usually fished for from shore - but they only come in close to shore before winter sets in ... now they are in deeper water ... so need sounder .. once at depth - I have portable Fish Finder I can drop over side ...

 

[Refueler]

Here's a quick vid showing the impellor and its 'condition' ...

 

[Bodach na mara]

Yes, it's Friar Tucked. Much worse than mine was when I got fed up with the erratic reading and rhythmic variation caused by the cable binding in the tube, while the impeller wound up the cable until it released and showed a ridiculous speed. So when the cable broke for the second time I removed the lot. I considered putting a bolt through the hole in the hull but ruled it out due to the problem of getting a seal on the ends that are not at right angles to the hull. I ended up using a large countersunk bit inside and outside then filled the hole with epoxy thickened with microfibres.
A bigger problem was the large hole in the cockpit bulkhead where the display was. I resorted to fixing on a bit of flat GRP that had been cut out under a berth when fitting something. (I can't remember what.) I fitted a NASA Target speed, mounting the paddle wheel unit through convenient bit of the hull clear on where slings would go. My depth gauge was a whirling neon type that never read over 12 fathoms and sometimes stopped whirling. So I bought a fishfinder of a make that seems to have vanished and fitted it by sticking down the transom-mounting transducer on the inside of the hull with a wodge of silicone.

PS The impeller and its mounting were in quite good shape and found a new home following an enquiry in the forum.