Please remember any fuses are there to protect the wiring, not the device connected to the wiring.  You want to use a fuse that will trip/blow before the wiring overheats.  You can overload wiring for short periods of time, but you want the fusing to be sized for constant current at the load.  An internet search should give you some good guidelines.

Rob

________________________________
From: Rhodes22-list <rhodes22-list-bounces at rhodes22.org> on behalf of ROGER PIHLAJA <roger_pihlaja at msn.com>
Sent: Saturday, May 25, 2024 9:53 AM
To: The Rhodes 22 Email List <rhodes22-list at rhodes22.org>
Subject: Re: [Rhodes22-list] Appropriate fuse for power lift winch (and Hello!)

Hi Rosie,

There is another reason not to put a bigger fuse in the electric outboard lift circuit.  I don’t know how much force a GBI outboard motor mount can handle.  But, if something were to jam or seize up, the winch you are proposing to use might be capable of pulling the motor mount apart if not fuse limited.  That sounds like the start of a bad day on the water to me!

Roger Pihlaja
S/V Dynamic Equilibrium
1978. Sanford, MI

Sent from my iPhone

> On May 25, 2024, at 9:20 AM, ROGER PIHLAJA <Roger_Pihlaja at msn.com> wrote:
>
> Hi Rosie,
>
> Assuming the wire runs, counting both + & - legs, are less than 5 meters and the wire runs are not at elevated temperature or thermally insulated, 10 AWG wire is rated for up to 30 amps in continuous service.  Your winch is capable of drawing much more than that if heavily loaded.  You are proposing to use the winch to lift an electric outboard?  Under normal service, the current draw should not blow the 30 amp fuse.  But, if something were to jam or seize up ... well that's what fuses are for.  Remember to use 10 AWG wire and a HD 12 VDC receptacle for your cockpit power port.  It would actually be better practice to put the power port on a smaller, more appropriately sized circuit.
>
> Roger Pihlaja
> S/V Dynamic Equilibrium
> 1978  Sanford, MI
> ________________________________
> From: Rhodes22-list <rhodes22-list-bounces at rhodes22.org> on behalf of Rosie Krueger <rosie.krueger at gmail.com>
> Sent: Saturday, May 25, 2024 8:49 AM
> To: rhodes22-list at rhodes22.org <rhodes22-list at rhodes22.org>
> Subject: [Rhodes22-list] Appropriate fuse for power lift winch (and Hello!)
>
> Hello all,
>
> New owners of a 2007 Rhodes 22 (formerly "Last Mango" - about to be
> renamed) in Vermont.  Thanks to the wonders of the archives and search
> function, I haven't posted yet because all of my questions had already been
> asked and answered sometime in the last 22 years - an amazing resource!
>
> Here's one I couldn't find though:
>
> The TLDR of my long explanation below is that I'm wondering if anyone has
> any input on the appropriate size fuse to use for the wiring leading to
> the power lift winch.  Will 30 Amps be too small?
>
> I am doing some preliminary wiring fixes before we launch.  A prior owner
> made some sloppy electrical additions, including a bunch of wire nut
> connections and other funky things that I want to clean up.  Thanks to a
> recommendation here, I got a copy of "Sailboat Electrics Simplified" and
> have been working my way through understanding everything.  One major issue
> seems to be that only a few of the (many!) wires leading out of the
> positive battery terminals have fuses.  I'm planning to remedy this by
> adding some terminal mount fuse blocks, with a separate fuse for each
> outgoing wire.
>
> One of the wires that is not fuse protected is the one that leads from the
> starter battery to the terminal connection in the lazarette.
> Previously, this terminal connection also powered the electric start
> outboard, but we've removed the gas outboard and switched to a battery
> powered epropulsion spirit - so we no longer need this terminal to do
> anything except power the winch for the lift, and power a separate line to
> an existing 12 v outlet in the cockpit.  I doubt we'll use the 12v outlet
> at the same time as the power lift, but it's possible we could forget
> something is plugged in.
>
> The wire leading from the "starter" battery to this terminal appears to be
> 10 AWG, although it's not actually labeled and is a little larger in
> diameter than the labeled 10 AWG wire that runs from the terminal to the
> winch. The winch is a Bad Land 2500 ATV winch and doesn't appear to have
> any legible labeling about its power draw or fuse size.  The manual for a
> similar winch has a chart showing a huge range in Amp draw from 10 - 132,
> with 10 Amps when pulling 0 kg at 4.1 mph and 55 amps when pulling 1000kg
> at 2.5 mph.  Based on that and the rule about sizing the fuse to save the
> wire, I'm thinking about trying a 30 amp fuse.  The type of battery mount
> terminal blocks available for 30 amps and below and 30 amps and above are
> different, so it wouldn't be a matter of just changing out the fuse if I
> initially go too small  (For those interested, I'm planning to use the Blue
> Sea ST-Blade Battery Terminal Mount Fuse Block - 5023 for everything else.
> For this use, would be choosing between that and Blue Sea Systems Single
> MRBF Terminal Fuse Block - 5191).  The larger MRBF fuses also seem like a
> specialty marine item that has to be special ordered - much less convenient
> for potential future replacement than the blade fuses available at my
> hardware store.
>
> So, any thoughts or input on this?  Do others have fuses on this wire? If
> so, what size?  If not, am I being overly cautious in installing a fuse
> here?
>
> Thanks, all!
> Rosie