Notice:
The advice given on this site is based upon individual or quoted experience, yours may differ.
The Officers, Staff and members of this site only provide information based upon the concept that anyone utilizing this information does so at their own risk and holds harmless all contributors to this site.
I think you could probably get away with it, but here is some info from animatedknots.com:
Knots Weaken Rope
They do! Angles, kinks, and knots, stress the fibers unevenly and weaken rope. If this concerns you, you are using rope that is not strong enough. Some knots in some ropes have been claimed to only weaken a rope to about 80% of its rated strength; other knots can weaken some rope to as little as 40%. For safety, therefore, assume that even brand new rope will perform at no more than 50% of its rated breaking strength. And, if the rope is old, worn, or damaged by sunlight or chemicals - expect considerably less. For some useful test results visit Dave Richards' Knot Break Strength vs Rope Break Strength on the National Speleological Society Website and Tom Moyer's website for: High Strength Cord Testing, Euro Death-Knot Testing, and Rope Gear and Testing,
And P/S's recent testing to failure of splices and knots in traditional and hi tech lines. If it is a permanently longer rode that you are seeking, high quality 3/8 twisted nylon (not from Home Depot) is pretty cheap and far and away your best choice. For temporary extensions, put an eye splice in the end of each rode, pass the bitter end of the added rode through both eyes and pull through so yo have interlocking eye splices. Strongest would be eye splices with thimbles connected with a shackle, but the splice will probably fail before either technique.
You could also splice the two lines together with a [url="http://en.wikipedia.org/wiki/Rope_splicing"]short splice[/url] which would be the strongest of the options available to you. That assumes you want to make a permanently longer line as opposed to a temporary extension. The short splice will be roughly 2x the diameter of the original line, but maintains the greatest amount of strength.
Given the option, I'd purchase new 3/8" nylon line to make up the rode you want. You can buy a 600' spool on Ebay for around $100 shipped. However, if you like doing marlinspike work like I do, splicing is a nice activity and a good skill to know.
If you choose to go with knotting 2 lines together, be sure to do a little research to find the best <i><b>bend</b></i> for connecting 2 lines together. Lots of references available.
Got to thinking about this and wondered how many of have a knot, probably a double bowline or similar, in the anchor line now. I guess if we do perhaps adding another knot would not make much of a difference.
<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote">Got to thinking about this and wondered how many of have a knot, probably a double bowline or similar, in the anchor line now.<hr height="1" noshade id="quote"></font id="quote"></blockquote id="quote">
I use a chain splice. I needed to learn how to do it because my powerboat has a windlass. It does make for a very smooth transition from the chain.
Notice: The advice given on this site is based upon individual or quoted experience, yours may differ. The Officers, Staff and members of this site only provide information based upon the concept that anyone utilizing this information does so at their own risk and holds harmless all contributors to this site.