Make a Towline (Well, How I did it anyway).

tambs

Yo BD! Color Screens-Invented Mid '50s. Jus sayin.
Oct 1, 2009
2,264
1,844
113
Tri-Cities, WA
Name
Tom
Boat
"Bottom Line" - 25' Carolina Classic SF
I'm no towing expert, nor claim to be any sort of line rigging expert. But, I do a fair amount of towing at work, and have used a number of different setups. This is one (of five) that I built recently, and they seem to be working pretty good. So I thought I'd share it with you all in case anyone is thinking of adding a towline to their own boat. I don't proclaim this as a best line/method/splice/etc., I just offer it up as something I've done that seems to be working out pretty well. I welcome any and all comments or suggestions for improvements.

I started with a 500' spool of Samson Amsteel Blue 12-strand single braid line, as this stuff has some pretty attractive characteristics. It has a low specific gravity, so it floats. This is pretty important at times when you might need to throttle down, and desire to keep any slack in the line from sinking into your prop. While floating line is nice, and helps, there's no substitute for having a crew member keeping a close watch on it. This line also has extremely low stretch, so the towed vessel is going to stay pretty much where you put it. Lines that stretch also tend to have a rubber band effect when they part, so a line that stretches but a little should be less inclined to come whipping past your head (or through it) in the unfortunate event that the line separates. The downside to a low-stretch line is that it can be rather unforgiving on hardware and attachment points. If you get a bit overzealous on the throttle while there's any slack in the line, all the energy will be transferred fairly harshly to mooring cleats, towing bits, bow eyes, line hardware, etc.

One of the nicest benefits of this particular line is its strength. Samson states that this 1/2" line has an average strength of 34,000 pounds, and a minimum strength of 30,600 pounds. All while weighing only 6.4 pounds per 100' of line. Other manufacturers offer similar products, and I don't intend this to sound like a Samson ad. Again, it is simply what I used.

A downside to this particular line is its cost. It's fairly expensive stuff at $2.79 a foot, so each of the five 100' lines I built set me back $279 for line only. Hopefully the stuff lives up to its billing, and lasts a long time.

I used a splicing guide from NE Ropes (Single Braid Eye Splice with a stitch) to splice in the eye. I followed this guide to the letter on the first line I built, but changed it up a bit on subsequent towlines. By the last line, I had added a tuck, increased the measurements from the bitter end to mark "A" to 4 fid lengths, and from mark "C" to mark "D" to 4 fid lengths instead of the three specified (to increase the length of the bury), and only marked and cut out 4 strand pairs (instead of the 5 specified) to make the taper in the bitter end.

To each line I added a 1/2" SST thimble to reduce chafing and wear, then a 1/2" dia. jaw and eye SST swivel, and finally a Wichard #367 snap hook (7,920 lb breaking load).


Eye size represented by Marks "A" and "B"


First tuck made.


Marks for subsequent tucks laid out.


Four tucks (instead of the 3 called for in the splicing guide). Ready to begin the bury.


Bury starts at "C"


And exits at "D"


Tucks pulled snug, bitter end exiting "D"


Marks laid out to cut strand pairs, to make the taper in the bitter end.


Cutting and removing strand pairs back to the bitter end.


Taper pulled back into the hollow core.


Snap hook (#367) I used.


This is the snap hook clip I use on our boat hooks. It can either be screwed or riveted (preferred) to the end of your telescoping boat hook, then you simply reach out, catch the bow eye with the open hook, and pull on the boat hook to release the snap from the boat hook and capture the vessel to be towed. No one needs get on the bow, and hang by the heels to attach a line, and you can maintain a respectable distance away with the towing vessel to get hooked up.

I did not do the lock stitch that the splicing guide calls for, as I did not feel it necessary. So far all 5 lines, plus the two 3/4" lines I made last year are holding up well, and show no signs of the splice slipping or failing.
 

POPEYE-SCOTT

Member
Sep 7, 2010
431
137
43
Tacoma, Wa
Name
Popeye
Boat
Sport Craft 252 Fishmaster
Good job. I have one 15 ft line that comes from bow eye to the cockpit. I can then use it direct for buoy tie off, or attach to anchor, drift sock or tow line without leaving the cockpit.
 

Clockwork

I've posted enough I should edit this section
Feb 16, 2011
2,544
1,709
113
covington, wa
Name
Ryan
Boat
GW Marlin
amsteel has no stretch though. really nice setup, but id put some sort of shock absorber in there.
 

5150

Member
Aug 4, 2004
747
28
28
60
California
Name
JB
Boat
Matson Inc.
amsteel has no stretch though. really nice setup, but id put some sort of shock absorber in there.
Got any photos of a shock absorber in this type of application? I made a tow line as well and thought of the shock absorber issue but did'nt know what to use or how to set it up.

Thanks if you can explain or have photos/drawings.
 

Clockwork

I've posted enough I should edit this section
Feb 16, 2011
2,544
1,709
113
covington, wa
Name
Ryan
Boat
GW Marlin
Got any photos of a shock absorber in this type of application? I made a tow line as well and thought of the shock absorber issue but did'nt know what to use or how to set it up.

Thanks if you can explain or have photos/drawings.
regular dock line over 5/8 would have enough stremph for this and has alot of stretch.
 

Tower Todd

Number #2
May 2, 2006
6,053
631
113
Touring the Pacific Ocean at 12 knots
www.mountainequipmentservices.com
Name
Todd S.
Boat
274' Long Range
I guess that will work.

J/K TAMBS, that is one mightly fine job that you did there and you will be glad to have it when the time comes to be towed or to tow someone. Hopefully by making these preperations now, you'll jinks yourself into having to never use it.

TT