In this photo I have lined up some of my wire crimper's. The one on the far left IS NOT A CRIMPER! I only say this because I have witnessed people putting together marine terminations with a pair of PLIERS.

The next crimper, the one with the yellow handles, is a cheap hardware store quality crimper and should only ever be used in an absolute emergency.

The middle crimper is a decent quality Klein crimper though it's not really well suited for much other than crimping non-insulated terminals.

The fourth crimper is a good quality crimper, made by Ancor Products, and designed specifically for crimping marine or aviation grade heat shrink terminations. The jaws of this crimper are precision machined, and wide enough in cross section, to produce an excellent crimp. This crimper is also of the ratcheting type and will not release until a proper crimp has been made.

The final crimper shown is another ratcheting type crimper but this one, set up with the jaws shown, is designed for insulated terminals.

Read on for more details on these different crimpers.

NOTE: There is no such thing as a "marine grade" terminal. I refer to "marine grade" only because that is what the retailers tout them as and what most boaters know them as. "Marine Grade" is just a high quality insulated or heat shrink crimp termination. The same terminals are sold into aviation, industry and marine applications. In aviation they are often referred to as aviation grade... The difference with aviation terminals is that they need to meet minimum standards and be crimped with "certified" tools all of which are FAR MORE EXPENSIVE than the average boater is willing to buy. I personally use aviation certified tools but the ones below will get you you to better than average...

This crimper is designed specifically for use with heat shrink connectors. While certainly not the best quality it is a decent mid grade tool and far better than using the wrong tool on expensive connectors.

This tool will not damage the heat shrink and will yield a very, very strong crimp when used on factory made heat shrink crimp connectors.

This pair is distributed by Ancor Products and are called the "Single Crimp Ratchet Tool" Part No. 702010.

I paid about $55.00 for this crimper at Hamilton Marine in Portland, Maine.

You can buy a nearly identical crimper, without the Ancor name, from Sailors Solutions for only $39.95.

Sailors Solutions Crimper (LINK)

A smooth well machined jaw surface is important when working with heat shrink connectors. This tool will not rip the heat shrink as a cheap tool will.

In this photo I have placed a marine grade adhesive lined heat shrink connector into the jaws of my Klein "dimple" / staking crimper. It certainly does not take a rocket scientist to understand why a dimple crimper should be avoided for use on an insulated terminal. Once you squeeze the grip the dimple can puncture the expensive terminals protective heat shrink thus rendering the protection you paid for virtually pointless.

Note: This Klein crimper shows a spot for insulated crimps and also says insulated & non-insulated for the dimple crimp slots. I can not, with a good conscience, recommend anyone using this particular crimper, or any crimper like this, on any heat shrink insulated termination.

Using inexpensive, one size fits all, crimp tools will probably not save you any money in the long run. If and when you do use a dimple/staking crimper the dimple should be made opposite the seam, always "saddle the seam" this means face the seam AWAY from the dimpler, not at it as I have shown.

In this photo I am showing the orientation many folks often use, it is incorrect. Doing this can split the brazed seam and cause the termination to fail at a very low pull out strain. If you must use a dimple type crimper the dimple should be be opposite the seam.

Perhaps the most lacking feature of a dimple or staking crimper is that you lose any sort of strain relief crimping on standard insulated crimps. The entire load is taken by just the crimp barrel.

A double crimp ratcheting tool is designed to make two crimps, one for strain relief, which has different sized dies, and one for the bare wire crimp. If you are trying to wire a boat to be ABYC compliant, which by the way is not a requirement for a DIY, a dimple or staking crimper would not qualify as the correct tool to use under E-11 for insulated terminals.

This photo shows a few of the different types of crimp terminals you can buy. The terminals in the top row are marine grade crimp connectors with built in adhesive lined heat shrink and are the best possible solution to use on a boat.

Technically there is such a thing as "marine grade" terminals but that is what the better quality stuff has become known as. Yes, heat shrink terminals are expensive, but in my opinion well worth it. They are available from manufacturers such as Ancor Products, AMP, and FTZ.

The second row of connectors are marine grade but non-heat shrink. While these terminals stand head and shoulders above the bottom row they are not sealed connections and as such are open to the marine environment. When used in conjunction with UL Listed tinned marine grade wire these crimp connectors will last a long time provided they are not in any direct contact with water such as in a bilge.

The third row represents Wal*Mart quality connectors that should be avoided on a boat. They vary tremendously in ID and OD diameters and as such it is a crap shoot as to how a crimp will turn out.

A good tip when buying connectors is this; if you can't see through the insulation, it's most likely vinyl, and should be avoided. The vinyl insulation on this type of connector can and will crack and the raw metal thickness, where the wire meets the connector to be crimped, is very, very weak in comparison to top quality terminals from reputable manufacturers such as those listed above.

OK, So I've ruined a few connectors for the sake of illustration, but, I did this to show what you should find beneath that tinned surface. I simply ground away the tinned coating to reveal the solid copper.